CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2004-205042, filed Jul. 12, 2004; No. 2005-004196, filed Jan. 11, 2005; and No. 2005-045783, filed Feb. 22, 2005, the entire contents of all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wideband antenna for transmitting and receiving radio waves and a communication apparatus having the antenna.
2. Description of the Related Art
An antenna having a structure in which two metal elements are disposed opposite to each other so that a gap is interposed between them is disclosed. (Refer to U.S. Pat. No. 4,843,403)
However, the transmitting and receiving band in a required frequency band may not be sufficiently extended merely by unconditionally forming the structure disclosed by U.S. Pat. No. 4,843,403.
BRIEF SUMMARY OF THE INVENTION
In view of the circumstances stated, it has been desired to surely extend the transmitting and receiving band in the required frequency band.
According to a first aspect of the present invention, there is provided a wideband antenna in which a first conductive element and a second conductive element are arranged so that a first notch of which the width becomes wider with getting apart from a reference point to be a power feeding point is formed between the first element and the second element, wherein the first element and the second element have shapes satisfying two conditions: (i) a sum of the lengths of one or more sides facing the first notch and a first side terminating at one edge of a wider opening of the first notch, these sides pertaining to the first element, and the lengths of one or more sides facing the first notch and a second side terminating at one edge of the wider opening of the first notch, these sides pertaining to the second element, is approximately half of a first wavelength corresponding to a first frequency within a required frequency band; and (ii) a sum of the lengths of one or more sides pertaining to the first element and facing the first notch, and the lengths of one or more sides pertaining to the second element and facing the first notch is approximately half of a second wavelength corresponding to a second frequency within the required frequency band, the second frequency being higher than the first frequency.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
FIG. 1 is a perspective view showing a structure of a wideband antenna regarding a first embodiment of the invention;
FIGS. 2A, 2B, 2C, 2D are illustrations explaining conditions to define sizes of conductive elements shown in FIG. 1;
FIGS. 3A, 3B are illustrations showing power feeding forms to the antenna shown in FIG. 1;
FIGS. 4A, 4B are illustrations showing characteristics of voltage standing wave ratio (VSWR) and a reflection coefficient of the antenna shown in FIG. 1;
FIGS. 5A, 5B are illustrations showing radiation patterns of the antenna shown in FIG. 1;
FIG. 6 is an illustration showing a first mounting method when mounting the antenna shown in FIG. 1 on a communication apparatus, etc.;
FIG. 7 is an illustration showing a second mounting method when mounting the antenna shown in FIG. 1 on a communication apparatus, etc.;
FIGS. 8A, 8B, 8C are illustrations showing procedures to mount the antenna by the second mounting method shown in FIG. 7;
FIG. 9 is an illustration showing a structure of a wideband antenna regarding a second embodiment of the invention;
FIGS. 10A, 10B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 9;
FIGS. 11A, 11B are illustrations showing radiation patterns of the antenna shown in FIG. 9;
FIG. 12 is a Smith chart with respect to the antenna shown in FIG. 9;
FIG. 13 is an illustration showing a structure of a wideband antenna regarding a third embodiment of the invention;
FIG. 14A, 14B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 13;
FIGS. 15A, 15B are illustrations showing radiation patterns regarding a horizontal plane of the antenna shown in FIG. 13;
FIG. 16 is a Smith chart with respect to the antenna shown in FIG. 13;
FIGS. 17A, 17B are illustrations showing radiation patterns regarding a vertical plane of the antenna shown in FIG. 13;
FIG. 18 is an illustration showing a structure of a wideband antenna regarding a fourth embodiment of the invention;
FIGS. 19A, 19B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 18;
FIG. 20 is an illustration showing a structure of a wideband antenna regarding a fifth embodiment of the invention;
FIGS. 21A, 21B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 20;
FIG. 22 is a perspective view showing a structure of a wideband antenna regarding a sixth embodiment of the invention;
FIGS. 23A, 23B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 22;
FIGS. 24A, 24B are illustrations showing radiation patterns regarding vertically polarized waves of the antenna shown in FIG. 22;
FIGS. 25A, 25B are illustrations showing radiation patterns regarding horizontally polarized waves of the antenna shown in FIG. 22;
FIG. 26 is an illustration showing an example of mounting of the antenna shown in FIG. 22;
FIG. 27 is an illustration showing an example of mounting of the antenna shown in FIG. 22;
FIG. 28 is a perspective view showing a structure of a wideband antenna regarding a seventh embodiment of the invention;
FIGS. 29A, 29B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 28;
FIGS. 30A, 30B, 30C are illustrations showing radiation patterns of vertically polarized waves at 3 GHz of the antenna shown in FIG. 28;
FIGS. 31A, 31B, 31C are illustrations showing radiation patterns of vertically polarized waves at 8 GHz of the antenna shown in FIG. 28;
FIG. 32 is a perspective view showing a structure of a wideband antenna regarding a eighths embodiment of the invention;
FIGS. 33A, 33B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 32;
FIGS. 34A, 34B are illustrations showing radiation patterns at 3 GHz of the antenna shown in FIG. 32;
FIGS. 35A, 35B are illustrations showing radiation patterns at 8 GHz of the antenna shown in FIG. 32;
FIG. 36 is a perspective view showing a structure of a wideband antenna regarding a ninth embodiment of the invention;
FIGS. 37A, 37B are illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 36;
FIGS. 38A, 38B are illustrations showing radiation patterns of the antenna shown in FIG. 36;
FIG. 39 is a perspective view showing a structure of a wideband antenna regarding a tenth embodiment of the invention;
FIGS. 40A, 40B are illustrations explaining conditions to define sizes of conductive elements shown in FIG. 39;
FIGS. 41A, 41B are illustrations showing power feeding forms to the antenna shown in FIG. 39;
FIG. 42 is an illustrations showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 39;
FIG. 43 is a Smith chart with respect to the antenna shown in FIG. 39;
FIGS. 44A-44G are illustrations showing radiation patterns of the antenna shown in FIG. 39;
FIGS. 45A, 45B are illustrations explaining advantages of the antenna shown in FIG. 39;
FIGS. 46A, 46B are illustrations explaining advantages of the antenna shown in FIG. 39;
FIG. 47 is an illustration showing a structure of a wideband antenna regarding a eleventh embodiment of the invention;
FIGS. 48A, 48B are illustrations explaining functions of notches shown in FIG. 47;
FIGS. 49A-49F are illustrations showing degrees of improvements of radiation patterns by the antenna shown in FIG. 47;
FIG. 50 is an illustration showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 47;
FIG. 51 is a Smith chart with respect to the antenna 1200 shown in FIG. 47;
FIGS. 52A-52G are illustrations showing radiation patterns of the antenna shown in FIG. 47;
FIG. 53 is an illustration showing a structure of a wideband antenna regarding a twelfth embodiment of the invention;
FIG. 54 is an illustration showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 53;
FIG. 55 is a Smith chart with respect to the antenna shown in FIG. 53;
FIG. 56 is a perspective view showing a structure of a wideband antenna regarding a thirteenth embodiment of the invention;
FIG. 57 is an illustration showing characteristics of VSWR and reflection coefficient of the antenna shown in FIG. 56;
FIG. 58 is a Smith chart with respect to the antenna shown in FIG. 56;
FIGS. 59A-59G are illustrations showing radiation patterns of the antenna shown in FIG. 56;
FIG. 60 is a perspective view showing a structure of a wideband antenna regarding a fourteenth embodiment of the invention;
FIG. 61 is an illustration showing a characteristics of a VSWR of the antenna shown in FIG. 60;
FIG. 62 is an illustration showing a radiation pattern of the antenna shown in FIG. 60;
FIG. 63 is a perspective view of a wideband antenna regarding a modified embodiment of the fourteenth embodiment;
FIG. 64 is a perspective view of a structure of a wideband antenna regarding a fifteenth embodiment of the invention;
FIG. 65 is an illustration showing a characteristics of a VSWR of the antenna shown in FIG. 64;
FIGS. 66A-66F are illustrations showing radiation patterns of the antenna shown in FIG. 64;
FIG. 67 is an illustration showing a structure of a communication apparatus regarding a sixteenth embodiment of the invention;
FIGS. 68A, 68B are illustrations showing structures of a communication apparatus regarding a seventeenth embodiment of the invention; and
FIG. 69 is an illustration showing a specific example achieving a conductive element as conductive patters formed on a substrate.
DETAILED DESCRIPTION OF THE INVENTION
The embodiments of the present invention will be explained with reference to the accompanying drawings. Structure of wideband antennas regarding each embodiment will be schematically shown so as to point out each feature specifically in the drawings referred to below. For example, each part will not be uniformly reduced in size and will be figuratively drawn in thickness.
First Embodiment
FIG. 1 is the perspective view showing the structure of the wideband antenna 100 regarding the first embodiment of the invention.
As shown in FIG. 1, the antenna 100 comprises the conductive elements 1, 2 and a dielectric substrate 3.
The elements 1, 2 are thin plates made of conductive material. The elements 1, 2 respectively have a pentagonal shape formed so that one side of a rectangular thin plate is linearly notched with the same angle from its center to both sides. The shapes of the elements 1, 2 are approximately congruent with each other.
Five sides of the element 1 are referred to as sides 1a, 1b, 1c, 1d and 1e as shown FIG. 1. The sides 1b, 1c are inclined sides provided with a shape so as to notch as mentioned above and contact each other. A top 1f is formed at a part at which the sides 1b, 1c contact with each other. The side 1a contacts the side 1b. The side 1d contacts the side 1c. The side 1e contacts the sides 1a, 1d, respectively.
Five sides of the elements 2 are referred to as sides 2a, 2b, 2c, 2d and 2e as shown in FIG. 1. The sides 2b, 2c are inclined sides provided with a shape so as to notch as mentioned above and contact each other. A top 2f is formed at a part at which the sides 2b, 2c contact each other. The side 2a contacts the side 2b. The side 2d contacts the side 2c. The side 2e contacts the sides 2a, 2d, respectively.
The elements 1, 2 are mounted on the dielectric substrate 3 in a manner that the tops 1f, 2f are opposed to each other. A small gap is provided between the tops 1f and 2f. The sides 1a, 2a and the sides 1d, 2d are disposed on the same straight lines, respectively.
Such arrangements of the elements 1, 2 described above forms two notches 4a, 4b interposing the tops 1f, 2f between the elements 1 and 2. That is, a notch 4a is formed between the sides 1b and 2b, and a notch 4b is formed between the sides 1c and 2c. The shapes of the notches 4a, 4b are approximately congruent with each other. The widths of the notches 4a, 4b are made narrowest between the tops 1f and 2f and are gradually made wider toward both side sections of the elements 1, 2. That is, the notches 4a, 4b extend in different directions from a reference point which is an intermediate point. The notches 4a, 4b have shapes in which the widths are made wider with getting apart form the reference point. Wider opening ends at which the notches 4a, 4b are made widest coincide with each one end of the sides 1a, 2a, 1d and 2d. Narrower opening ends at which the notches 4a, 4b are made narrowest coincide with each one end of the sides 1b, 1c, 2b and 2c.
The sizes of the elements 1, 2 are decided in consideration with a required frequency range. That is, two frequencies f1, f2 (f1<f2) are defined in the required frequency band and wavelength corresponding to the frequency f1, f2 is referred to λ1, λ2. A length L1 from an end P1 of the side 1a to an end P2 of the side 2a along with the sides 1a, 1b, 2b, 2a as shown by a solid line in FIG. 2A, and a length L2 from an end P3 of the side 1d to an end P4 of the side 2d along with the sides 1d, 1c, 2c, 2d as shown by a solid line in FIG. 2B are set to approximately λ1×½. A length L3 from an end P5 (positioned at the wider opening end of the notch 4a) of the side 1b to an end P6 (positioned at the wider opening end of the notch 4a) of the side 2b along with the sides 1b, 2b as shown by a solid line in FIG. 2C, and a length L4 from an end P7 of the side 1c to an end P8 of the side 2c along with the sides 1c, 2c as shown by a solid line in FIG. 2D are set to approximately λ2×½. Although the lengths L1, L2 should be set to λ1×½ ideally, i.e. λ1×0.5, extent from λ1>×0.4 to λ1×0.6 may be sufficient.
The gap between the tops 1f and 2f is very narrow in comparison with lengths of each side of the elements 1, 2. So that, the lengths L1, L2 substantially equal the sum of each length of the sides 1a, 1b, 2a, 2b or the sum of each length of the sides 1c, 1d, 2c, 2d.
The antenna 100 structured as mentioned above has a power feeding point between a point near the top 1f and a point near the top 2f.
FIGS. 3A, 3B are the illustrations showing the power feeding forms for the antenna 100. As shown in FIG. 3A, an inner conductor 27a of a coaxial cable 27 is soldered to the element 1 near the top 1f and an outer conductor 27b is soldered to the element 2 near the top 2f. With such a structure, the feeding point is positioned near the reference point as shown in FIG. 3B.
FIGS. 4A, 4B are illustrations showing characteristics of the voltage standing wave ratio (VSWR) and the reflection coefficient when power is fed between the tops 1f and 2f if the frequencies f1, f2 are set to 3.4 GHz, 7.3 GHz. By a simulation destined to a model shown in FIG. 4A, the characteristics shown in FIG. 4B are obtained.
As shown in FIGS. 4A, 4B, the two frequencies of f1, f2 become resonance points and the VSWR and the reflection coefficient become extremely small. Though the VSWR as to intermediate frequencies between the frequencies f1, f2 become larger than that at the frequencies f1, f2, it can be suppressed sufficiently small. AS a frequency becomes lower than the frequency f1, or as the frequency becomes higher than the frequency f2, the VSWR increases extremely. For example, if required VSWR is set not larger than 3, a bandwidth about 2.6 GHz-9.4 GHz becomes a transmittable/receivable band in the example shown in FIGS. 4A, 4B.
According to the antenna 100, wide transmittable/receivable band can be obtained by a combination of two resonant frequencies. However, since the VSWR at the intermediate frequency between the frequencies f1 and f2 could become excessively large due to the excessive difference between the frequencies f1 and f2, the frequencies f1, f2 should be appropriately selected so that the VSWR does not become excessively large.
The antenna 100 radiates vertically polarized waves. Since the shapes of the elements 1, 2 are approximately congruent with each other, symmetric radiation patterns can be obtained as shown in FIGS. 5A, 5B. FIG. 5A shows a cross section pattern on a vertical plane, and FIG. 5B shows a cross section pattern on a horizontal plane.
Since each side of the elements 1, 2 of the antenna 100 is formed in a linear shape, the structure of the antenna 100 facilitates its manufacturing in comparison with the structure disclosed by the U.S. Pat. No. 4,843,403.
FIG. 6 is the illustrate showing the first mounting method when mounting the antenna 100 on the communication apparatus, etc.
By the mounting method shown in FIG. 6, an opening 4a for mounting an antenna is disposed at a metal housing 4 of a device on which the antenna is mounted and the antenna 100 is mounted on the opening 4a from behind the housing 4.
By adopting such a mounting method, running change of the antenna 100 can be performed, and radio waves can be easily received thereby.
FIG. 7 is the illustration showing the second mounting method when mounting the antenna 100 on the communication apparatus, etc.
By the mounting method shown in FIG. 7, an opening 5a for mounting an antenna is disposed at a metal housing 5 of a device on which the antenna is mounted and the antenna 100 is mounted on the opening 5a by using tools 6a, 6b.
FIGS. 8A, 8B, 8C are illustrations showing the procedures to mount the antenna 100 by the second mounting method.
Each tool 6a, 6b has two groves and H-like cross sections. As shown in FIG. 8A, the grooves of the tools 6a, 6b are respectively engaged at a top and a bottom of the opening 5a. Next, as shown in FIG. 8B, a lower end of the antenna 100 is engaged with the groove of the tool 6a, further, as shown by arrows, un upper end of the antenna is pushed into the groove of the tool 6a. Then, as shown in FIG. 8C, the upper end of the antenna 100 is engaged with the groove of the tool 6a.
By adopting the second mounting method, the antenna 100 can be easily and surely fixed to the metal housing 5.
Second Embodiment
FIG. 9 is the illustration showing the structure of the wideband antenna 200 regarding the second embodiment of the invention. In FIG. 9, the same parts as those of FIG. 1 designated by the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 9, the antenna 200 comprises conductive elements 7 and 8. These elements 7, 8 are mounted on a dielectric substrate, but the substrate is not shown.
The elements 7, 8 are thin plates made of conductive material. The elements 7, 8 respectively have a pentagonal shape formed so that a first side of a rectangular thin plate is linearly notched with the same angle from its center to both sides and so that a second side facing the first side is linearly notched from one end of the second side. The shapes of the elements 7, 8 are approximately congruent with each other.
Five sides of the element 7 are referred to as sides 7a, 7b, 7c, 7d and 7e as shown in FIG. 9. Five sides of the element 8 are referred to as 8a, 8b, 8c, 8d and 8e as shown in FIG. 9. In this case, the sides 7b, 7c, 8b and 8c, correspond to the sides 1b, 1c, 2b and 2c of the antenna 100, respectively, and the elements 7, 8 are arranged so that the sides 7b, 7c, 8b and 8c have relations similar to the sides 1b, 1c, 2b and 2c. Accordingly, the notches 4a, 4b are formed between the elements 7 and 8 in the same way in the first embodiment.
Since the side 7e is inclined to the side 7a, 7b, the side 7a becomes shorter than the side 7d. Since the side 8e is inclined to the sides 8a, 8d, the side 8d becomes shorter than the side 8a. However, as shown in FIG. 9, since the sides 7a, 8a are positioned on the same straight line and the sides 7d, 8d are positioned on the same straight line, the length from an end of the side 7a up to an end of the side 8b along with the sides 7a, 7b, 8b, 8a becomes equal to the length from an end of the 7d up to an end of the 8d along with the sides 7d, 7c, 8c, 8d. Therefore, each of the these lengths can be set λ½ similar to the lengths L1, L2 in the first embodiment.
FIGS. 10A, 10B are illustrations showing the characteristics of the VSWR and the reflection coefficient of the antenna 200. By a simulation destined to a model shown in FIG. 10A, the characteristics shown in FIG. 10B are obtained.
As is known from FIGS. 10A, 10B, also the antenna 200 as well as the antenna 100, can offers wide transmittable/receivable band by a combination of two resonant frequencies. Moreover, the antenna 200 has flexibility in shape higher than the antenna 100 and facilitates to be an appropriate shape in response to a situation of a mounting space.
FIGS. 11A, 11B are illustrations showing the radiation pattern of the antenna 200, the FIG. 11A shows a three-dimensional pattern and FIG. 11B shows a cross section pattern on a horizontal plane. FIG. 12 is the Smith chart with respect to the antenna 200.
As is known from FIGS. 10A, 10B and FIG. 12, the antenna 200 can maintain excellent radiation characteristics even though it has a vertically asymmetric shape.
Third Embodiment
FIG. 13 is an illustration showing the structure of the wideband antenna 300 regarding the third embodiment of the invention. In FIG. 13 the same parts as that of FIG. 1 designated by the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 13, the antenna 300 comprises the elements 2 and an element 9. These elements 2, 9 are mounted on a dielectric substrate, but the substrate is not shown in FIG. 13. That is, the antenna 300 is equipped with the element 9 instead of the element 1 of the antenna 100.
The element 9 is a thin plate made of conductive material. The element 9 has a shape in which a part of the element 1 is notched in rectangle from the side of the side 1e of the element 1 and a notch 9a is provided. The element 9 is arranged opposite to the element 2 in the same positional relationship.
The element 9 has the sides 1a, 1b, 1c, 1d and the top 1f of the element 1 as they are. These sides are in the same positional relationship to the sides 2a, 2b, 2c, 2d and the top 2f as that of the antenna 100.
FIGS. 14A, 14B are the illustrations showing the characteristics of the VSWR and the reflection coefficient of the antenna 300. By a simulation destined to a model shown in FIG. 14A the characteristics shown in FIG. 14B are obtained.
As is known from FIGS. 14A, 14B, also the antenna 300 as well as the antenna 100, can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
Moreover, the antenna 300 increases the flexibility in mounting because components, etc. can be arranged at the notch 9a.
FIGS. 15A, 15B are illustrations showing the radiation patterns on a horizontal plane of the antenna 300, the FIG. 15A shows a three-dimensional pattern and FIG. 15B shows a cross section pattern on a horizontal plane. FIG. 16 is the Smith chart with respect to the antenna 300. FIGS. 17A, 17B shows the radiation patterns on a vertical plane of the antenna 300, and FIG. 17A shows the pattern as a three-dimensional pattern and FIG. 17B shows the pattern as a cross section pattern on a vertical plane.
As is known from FIGS. 14A, 14B to FIGS. 17A, 17B, the antenna 300 becomes excellent in the radiation characteristics even though the shapes of the elements 2, 9 are not congruent with each other. However, as shown in FIGS. 17A, 17B, the radiation patterns on the vertical plane present directivity. This directivity can be adjusted by varying the size of the notch 9a of the element 9.
Fourth Embodiment
FIG. 18 is the illustration showing the structure of the wideband antenna 400 regarding the forth embodiment of the invention. In FIG. 18 the same parts as those of FIG. 1 designated by the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 18, the antenna 400 comprises the elements 9 and an element 10. These elements 9, 10 are mounted on a dielectric substrate, but the substrate is not shown in FIG. 18. That is, the antenna 400 is equipped with the elements 9, 10 instead of the elements 1, 2 of the antenna 100.
The element 10 is a thin plate made of conductive material. The element 10 has a shape in which a part of the element 2 is notched in rectangle from the side of the side 2e of the element 2 and a notch 10a is provided. The shape, size or position of the notch 10a may have nothing to do with the notch 9a, however, the notch 10a is formed similarly to the notch 9a so that the element 9 become approximately congruent with the element 10. The elements 9, 10 are arranged opposite each other in the same positional relationship as that of the elements 1, 2.
The element 10 is provided with the sides 2a, 2b, 2c, 2d and the top 2f of the element 2 as they are. These sides are in the same positional relationship to the sides 1a, 1b, 1c, 1d and the top 1f as those of the antenna 100.
FIGS. 19A, 19B are illustrations showing the VSWR and the reflection coefficient of the antenna 400. By a simulation destined to a model shown in FIG. 19A the characteristics shown in FIG. 19B are obtained.
As is known from FIGS. 19A, 19B, also the antenna 400 as well as the antenna 100 can offer a wide transmittable/receivable band by a combination of two resonant frequencies.
Moreover, the antenna 400 becomes to make it possible to arrange components, etc., even at the notch 10a in addition to the notch 9a, so that the flexibility in mounting is improved more than that of the antenna 300.
Fifth Embodiment
FIG. 20 is an illustration showing the structure of the wideband antenna 500 regarding the fifth embodiment of the invention. In FIG. 20, the same parts as those of the FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.
As shown in FIG. 20, the antenna 500 comprises the element 2 and a conductive element 11. These elements 2, 11 are mounted on a dielectric substrate, but the substrate is not shown. That is, the antenna 500 is equipped with the element 11 instead of the element 1 of the antenna 100.
The element 11 is a thin plate made of conductive material. The element 11 has a shape in which a part of the element 1 is notched in arch from the side of the side 1e of the element 1 and a notch 11a is provided. The element 11 is arranged opposite to the element 2 in the same positional relationship as that of the element 1.
The element 11 has the sides 1a, 1b, 1c, 1d and the top 1f of the element 1 as they are. These sides are in the same positional relationship to the sides 2a, 2b, 2c, 2d and the top 2f as that of the antenna 100.
FIGS. 21A, 21B are the illustrations showing the characteristics of the VSWR and the reflection coefficient of the antenna 500. By a simulation destined to a model shown in FIG. 21A, the characteristics shown in FIG. 21B are obtained.
As known from FIGS. 21A, 21B, also the antenna 500 as well as the antenna 100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
Moreover, the antenna 500 makes it possible to arrange components, etc., at the notch 11a, so that the flexibility in mounting is improved.
Furthermore, as known from this fifth embodiment and the third and the fourth embodiments, any shape of notch may be acceptable, only if the two elements 2, 11 have shapes so that the sides 1a, 1b, 1c, 1d, the top 1f and the sides 2a, 2b, 2c, 2d, the top 2f are provided as they are.
Sixth Embodiment
FIG. 22 is the perspective view showing the structure of the wideband antenna 600 regarding the sixth embodiment of the invention. In FIG. 22 the same parts as those of FIG. 1 are referred to the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 22, the antenna 600 comprises the conductive elements 1, 2 and a dielectric substrate 12.
The substrate 12 is shaped so that the center of the dielectric substrate 3 is squarely bent. Hereinafter, two parts of the substrate 12 having different directions are referred to a vertical part 12a and a horizontal part 12b.
The elements 1, 2 are attached to the vertical part 12a and the horizontal part 12b of the substrate 12, in a state so that the top 1f and the top 2f are opposed to each other. A small gap is disposed between the top 1f and the top 2f. The sides 1a and 2a are positioned on two straight lines intersecting orthogonally with each other, and the sides 1d and 2d are positioned on another two straight lines intersecting orthogonally with each other.
Such arrangements of the elements 1, 2 forms two notches 13a, 13b by interposing the tops 1f, 2f between the elements 1 and 2. That is, the notch 13a is formed between the side 1b and the side 2b, and the notch 13b is formed between the sides 1c and the side 2c. The shapes of these notches 13a, 13b are approximately congruent with each other. The widths of the notches 13a, 13b are narrowest between the top 1f and the top 2f and gradually become wider toward both sides of the elements 1, 2.
Even the antenna 600 with such a structure, a resonant point is defined in the same way as that of the antenna 100.
FIGS. 23A, 23B are the illustrations showing the characteristics of the VSWR and the reflection coefficient of the antenna 600. By a simulation destined to a model shown in FIG. 23A, the characteristics shown in FIG. 23B are obtained.
As is known from FIGS. 23A, 23B, also the antenna 600 as well as the antenna 100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
FIGS. 24A, 24B are illustrations showing radiation patterns of vertically polarized waves of the antenna 600. FIG. 24A shows a three-dimensional pattern and FIG. 24B shows a cross section pattern on a horizontal plane. FIGS. 25A, 25B are illustrations showing radiation patterns of horizontally polarized waves of the antenna 600, FIG. 25A shows a three-dimensional pattern and FIG. 25B shows a cross section pattern on a horizontal plane.
As known from FIGS. 24A, 24B and FIGS. 25A, 25B, the antenna 600 can radiates both vertically and horizontally polarized waves. Because the element 1 is toward in a vertical direction and the element 2 is toward in a horizontal direction.
As shown in FIG. 26, the antenna 600 can be mounted on an edge of a video recorder, and as shown in FIG. 27, on an edge of a personal computer then can be efficiently mounted.
Seventh Embodiment
FIG. 28 is the perspective view showing the structure of the wideband antenna 700 regarding the seventh embodiment of the invention. In FIG. 28 the same parts as those of FIG. 1 are referred to the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 28, the antenna 700 comprises conductive elements 14, 15 and a dielectric substrate 16.
The elements 14, 15 are shaped in such a manner to squarely bend the elements 1, 2 on a center line passing through the tops 1f, 2f. Thus, the elements 14, 15 present shapes equivalent to those of the elements 1, 2 by developing themselves, and respectively have the sides 1a, 1b, 1c, 1d, and 2a, 2b, 2c, 2d and the tops 1f and 2f of the elements 1, 2 as they are.
The elements 14, 15 are attached to the dielectric substrate 16, respectively, in a state so that the tops 1f, 2f are opposed to each other. A small gap is provided between the top 1f and the top 2f. The sides 1a, 2a and the sides 1d, 2d are respectively positioned on the respective straight lines.
Such arrangements of the elements 14, 15 form notches 4a, 4b are formed between the elements 14 and 15 in the same way as that of the antenna 100. However, the notches 4a, 4b are intersected orthogonally with each other.
FIGS. 29A, 29B are the illustrations showing the characteristics of the VSWR and the reflection coefficient of the antenna 700. By a simulation destined to a model shown in FIG. 29A, the characteristics shown in FIG. 29B are obtained.
As is known from FIGS. 29A, 29B, also the antenna 700 as well as the antenna 100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
FIGS. 30A, 30B, 30C are illustrations showing radiation patterns of vertically polarized waves at 3 GHz of the antenna 700, FIG. 30A shows as a three-dimensional pattern, FIG. 30B shows as a cross section pattern on a vertical plane and FIG. 30C shows a cross section pattern on a horizontal plane. FIGS. 31A, 31B, 31C are illustrations showing radiation patterns of vertically polarized waves at 8 GHz of the antenna 700, FIG. 31A shows a three-dimensional pattern, FIG. 31B shows a cross section pattern on a vertical plane and FIG. 31C shows a cross section pattern on a horizontal pattern.
As known from these FIGS. 30A, 30B, 30C and FIGS. 31A, 31B, 31C, the antenna 700 has a radiation pattern symmetrical with respect to low frequencies within a band, however, has a radiation pattern with a diversity stronger than that of the antenna 100 with respect to high frequencies.
Thereby, the antenna 700 can be mounted on the edge of the housing, etc., like the antenna 600 and can be efficiently mounted.
Eighth Embodiment
FIG. 32 is a perspective view showing the structure of the wideband antenna 800 regarding the eighth embodiment of the invention. In FIG. 32 the same parts as those of FIG. 1 are referred to the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 32, the antenna 800 comprises conductive elements 17, 18 and a dielectric substrate 19.
The elements 17, 18 are shaped in such a manner that the elements 1, 2 are squarely bent on a center line passing through the tops 1f, 2f and both ends of the elements 1, 2 are squarely bent inward. Thus, the elements 17, 18 are formed in square column shapes. However, gaps 17a, 18a are formed between the ends of the elements 17, 18. Since the elements 17, 18 present shapes equivalent to those of the elements 1, 2 by developing themselves, and respectively have the sides 1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d and the tops 1f, 2f as they are.
The elements 17, 18 are attached to the dielectric substrate 19, in a state so that the tops 1f, 2f are opposed to each other. A small gap is provided between the top 1f and the top 2f. The sides 1a, 2a and the sides 1d, 2d are positioned on the respective straight lines.
Such arrangements of the elements 17, 18 form notches 60a, 60b between the elements 17 and 18 in the same way as that of the antenna 100. The shapes of the notches 60a, 60b are approximately congruent with each other. Each width of the notches 60a, 60b is narrowest between the tops 1f and 2f and gradually becomes wider toward both side sections of the elements 17, 18.
FIGS. 33A, 33B are the illustrations showing the characteristics of the VSWR and the reflection coefficient of the antenna 800. By a simulation destined to a model shown in FIG. 33A, the characteristics shown in FIG. 33B are obtained.
As is known from FIGS. 33A, 33B, also the antenna 800 as well as the antenna 100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
FIGS. 34A, 34B are illustrations showing radiation patterns of vertically polarized waves at 3 GHz of the antenna 800, FIG. 34A shows as a three-dimensional pattern, and FIG. 34B shows as a cross section pattern on a vertical plane. FIGS. 35A, 35B are illustrations showing radiation patterns of vertically polarized waves at 8 GHz of the antenna 800, FIG. 35A shows as a three-dimensional pattern and FIG. 35B shows as a cross section pattern on a vertical plane.
As known from these FIGS. 34A, 34B and FIGS. 35A, 35B, the antenna 800 has a radiation pattern symmetrical with respect to low frequencies within a band, however, has a radiation pattern with a diversity stronger than that of the antenna 100 with respect to high frequencies. Thereby, the antenna 800 is appropriate for an application required the diversity.
Ninth Embodiment
FIG. 36 is the perspective view showing the structure of the wideband antenna 900 regarding the ninth embodiment of the invention. In FIG. 36, the same parts as those of FIG. 1 are referred to the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 36, the antenna 900 comprises conductive elements 20, 21 and a dielectric substrate 22.
The elements 20, 21 respectively have shapes which are cut off and formed by forming notches 23a, 23b onto a thin plate made of one piece of conductive material having an approximately square shape. Each notch 23a, 23b has a shape in linear symmetry with line segments 24a, 24b as the centers to cut off the thin plate from the thin plate described above, wherein the cut-off thin plate is smaller than the thin plate described above and approximately square. Each width of the notches 23a, 23b gradually becomes wider toward both side sections of the elements 20, 21. The shapes of the notches 23a, 23b are approximately congruent with each other.
The elements 20, 21 are attached onto the dielectric substrate 3 in a state to maintain a relative positional relationship so that the notches 23a, 23b to stay in the states described above.
The element 20 has four sides. As shown in FIG. 36, these four sides of the elements 20 are sides 20a, 20b, 20c and 20d. The sides 20b, 20c are the sides facing the notches 23a, 23b, and contact each other. A top 20e is formed at the part with which the sides 20b, 20c contact each other. The side 20a contacts the side 20b. The side 20d contacts the sides 20a and 20c.
The element 21 has six sides. As shown in FIG. 36, these six sides are sides 21a, 21b, 21c, 21d, 21e and 21f. The sides 21b, 21c are the sides facing the notches 23a, 23b, and contact each other. A valley section 21g is formed at the part with which the sides 21b, 21c contact each other. The side 21a contacts the side 21b, and the side 21d contacts the side 21c.
The top 20e of the element 20 and the valley section 21g of the element 21 are opposed to each other. A small gap is provided between the top 20e and the valley section 21g. The sides 20a, 21a and the sides 20d, 21d are positioned on the same straight lines, respectively.
The antenna 900 structured in a manner as described above is different in shape from the antenna 100 in a manner that the valley section 21g but not the top 20e is formed at the part with which the sides 21b 21c contact each other, however, it is possible for the sides 20a, 20b, 20c, 20d, 21a, 21b, 21c and 21d to be considered to correspond to the sides 1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d of the antenna 100, respectively. The lengths of the sides 20a, 20b, 20c, 20d, 21a, 21b, 21c, 21d are set to the same lengths as those of the sides 1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d of the antenna 100.
FIGS. 37A, 37B are the illustrations showing the characteristics of the VSWR and the reflection coefficient of the antenna 900. By a simulation destined to a model shown in FIG. 37A, the characteristics shown in FIG. 37B are obtained.
As is known from FIGS. 37A, 37B, also the antenna 900 as well as the antenna 100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
The antenna 900 has the notches 23a, 23b intersecting orthogonally with each other, so that the antenna 900 can direct one of the notches 23a, 23b toward a vertical direction and direct the other toward a horizontal direction. By using the antenna 900 in such an attitude, the antenna 900 can transmit and receive the vertically polarized waves and the horizontally polarized waves.
FIGS. 38A, 38B are illustrations showing radiation patterns of the antenna 900, FIG. 38A shows a radiation pattern of the vertically polarized waves as a cross section pattern on a vertical plane, and FIG. 38B shows a radiation pattern of the horizontally polarized waves as a cross section pattern on a vertical plane.
Tenth Embodiment
FIG. 39 is the perspective view showing the structure of the wideband antenna 1100 regarding the tenth embodiment of the invention.
As shown in FIG. 39, the antenna 1100 comprises conductive elements 31, 32 and a dielectric substrate 33.
The elements 31, 32 are thin plates made of conductive material. Each element 31, 32 are shaped in trapezoid in which only one side is inclined. The elements 31, 32 are approximately symmetric in shape with each other.
As shown in FIG. 39, four sides of the element 31 are sides 31a, 31b, 31c and 31d. The side 31b is the inclined side as described above. Each side 31a, 31c contacts opposed ends of the side 31b. The sides 31a, 31c are approximately parallel to each other. A top 31e is formed at a part with which the side 31a, 31b are contacted. The opposed ends of the side 31d contact the sides 31a and 31c, respectively.
As shown in FIG. 39, four sides of the element 32 are sides 32a, 32b, 32c and 32d. The side 32b is the inclined side as described above. Each side 32a, 32c contacts opposed ends of the side 32b. The sides 32a, 32c are approximately parallel to each other. A top 32e is formed with which the sides 32a, 32b are contacted. The opposed ends of the side 32d contact the sides 32a and 32c, respectively.
The elements 31, 32 are mounted on the same surface of the substrate 33 in a state that the tops 31e, 32e are opposed to each other. A small gap is provided between the tops 31e and the 32e. The sides 31a, 32a and the sides 31c, 32c are respectively positioned on the same straight lines.
By such arrangements of the elements 31, 32 described above, a notch 34 is formed between the elements 31 and 32. The width of the notch 34 is narrowest between the tops 31e and 32e, and gradually becomes wider with getting apart from the tops 31e, 32e. That is, the notch 34 is shaped so that the notch 34 makes an intermediate point of the tops 31e, 32e be a reference point and has a width becoming wider with getting apart from the reference point. A wider opening end at which the notch 34 becomes widest coincides with each one end of the sides 31c, 32c.
Sizes of the elements 31, 32 are defined in consideration with the required frequency band. That is, two frequencies f1, f2 (f1<f2) within the frequency band, and wavelength of the frequencies f1, f2 are set to λ1, λ2. As shown by a solid line in FIG. 40A, the length L11 from an end P11 of the side 31c up to an end P12 of the side 32c along with the sides 31c, 31b, 32b, 32c is set to approximately λ1×½. As shown by a solid line in FIG. 40B, the length L12 from an end P13 (positioned at an wider opening end of the notch 34) of the side 31b up to an end P14 (positioned at an wider opening end of the notch 34) of the side 32b is set to approximately λ2×½. Although the lengths L11 should be λ1×½, i.e., λ1×0.5 ideally, the extent from λ1×0.4 to λ1×0.6 may be sufficient. Although the lengths L12 should be λ2×0.5 ideally, the extent from λ2×0.4 to λ2×0.6 may be sufficient.
The gap between the top 31e and the top 32e is very small in comparison with the lengths of each side of the elements 31, 32. Whereby, the length L11 is substantially equal to the sum of the respective lengths of the sides 31b, 31c, 32b and 32c. The length L12 is substantially equal to the sum of the respective lengths of the sides 31b and 32b.
The elements 31, 32 can be made of, for example, sheet metal, flexible substrate, insert molding, MID (plated resin), etc.
The antenna 1100 structured in the manner described above sets a power feeding point between a section near the top 31e and a section near the top 32e, i.e., at a section near the reference point.
FIG. 41A, 41B are the illustrations showing forms of power feeding to the antenna 1100. As shown FIG. 41A, an inner conductor 27a of a coaxial cable 27 is soldered to the element 31 in the vicinity of the top 31e. An outer conductor 27b of the cable 27 is soldered to the element 32 in the vicinity of the top 32e. By such a structure shown in FIG. 41B, the feeding point is positioned at the section near the reference point.
FIG. 42 is the illustration showing the characteristics of the VSWR and the reflection coefficient when the frequencies f1 and f2 are set to 3.6 GHz and 8.1 GHz, and when power is fed between the top 31e and the 32e.
As shown in FIG. 42, the two frequencies f1, f2 become resonant points, and the VSWR and the reflection coefficient become extremely small. The VSWR as to intermediate frequencies between the frequencies f1 and f2 becomes larger than at the frequencies f1 and f2, however, the VSWR is suppressed sufficiently small. As the frequency becomes lower than the frequency f1, or as the frequency becomes higher than the frequency f2, the VSWR increases drastically. For example, if the upper limit of the required VSWR is set to around 3, the range of about 3.0 GHz-9.8 GHz becomes the transmittable/receivable band in an example shown in FIG. 42.
The antenna 1100 as described above, a wider transmittable/receivable band can be obtained by a combination of two resonant frequencies. By appropriately setting the frequencies f1 and f2, the transmittable/receivable band can coincide with the required frequency band. However, if the difference between the frequencies f1 and f2 is set excessively large, it is feared that the VSWR at the intermediate frequency between the frequencies f1 and f2 becomes excessively large, so that the frequencies f1 and f2 should be appropriately set within a range so as not to produce such a state.
FIG. 43 is the Smith chart with respect to the antenna 1100. FIGS. 44A-44G are the illustrations showing radiation patterns of the antenna 1100. FIGS. 44B-44D show radiation patterns on an XY plane of a coordinate system shown in FIG. 44A, and FIGS. 44E-44G show radiation patterns on an XZ plane of the coordinate system shown in FIG. 44A. Moreover, FIG. 44B and FIG. 44E show radiation patterns at 3 GHz, FIG. 44C and FIG. 44F show radiation patterns at 5 GHz, and FIG. 44D and FIG. 44G show radiation patterns at 8 GHz.
As known from these FIG. 43 and FIGS. 44A-44G, the antenna 1100 can obtain radiation patterns excellent in balance in the whole range of the transmittable/receivable band. Although the balance of the radiation patterns in a high-frequency range is disturbed, the disturbance is of such a level as is no practical problem.
The element 31 has sides 31a and 31c approximately parallel to each other. Thereby, the width of the element 31 in a direction orthogonally intersection to the sides 31a, 31b can be suppressed to a minimum width to form the notch 34 satisfying the condition described above. Whereby, the antenna 1100 can be downsized.
For example, the antenna 1100 can reduce its width in the direction described above to be half as wide as the antenna 100. The antenna 1100 has advantages as follows in mounting on a communication terminal.
For example, the antennas 100, 1100 are sometimes housed in a housing of the communication terminal together with a liquid crystal display. At this time, as shown FIGS. 45A, 45B, a metal frame 28a to support the liquid crystal display is mounted on a housing 28. The antennas 100, 1100 are disposed inside the housing 28 so as to get off the metal frame 28a.
In this case, as clarified by FIGS. 45A, 45B, it is possible to make a distance D1 from a power feeding point up to the metal frame 28a of the antenna 1100 longer than a distance D2 from the power feeding point up to the metal frame 28a of the antenna 100. Thereby, the antenna 1100 can suppress electromagnetic field coupling by the metal frame 28a in comparison with the antenna 100 and reduce disturbance of radiation characteristics.
On the other hand, the housing 28 also houses a circuit board. Preferably components to be mounted on the circuit board are arranged apart from a wideband antenna in some case.
In this case, as clarified by FIGS. 46A, 46B, the antenna 1100, rather than the antenna 100, is arranged apart from a component 30 mounted on a circuit board 29. Since the space in which a component can be mounted apart from the antenna 1100 becomes large resulting from the use of the antenna 1100, the antenna 1100 allows a further large-sized component shown by a dot line to be mounted instead of the component 30, or allows an another component to be mounted between the antenna 1100 and the component 30. That is, the use of the antenna 1100 improves the flexibility in arranging the component.
Since each side of the elements 31, 32 of the antenna 1100 formed in a straight line shape, the antenna 1100 becomes easy to be manufactured in comparison with the structure of a wideband antenna described in U.S. Pat. No. 4,843,403.
The power feeding point of the antenna 1100 is positioned at the end thereof. Whereby, a signal wire, etc., to feed power to the feeding point is easily positioned. The mounting of the antenna 1100 on a communication apparatus allows the feeding point not to overlap on other device such as a display while overlapping and disposing most of the antenna 1100 with the other device.
Eleventh Embodiment
FIG. 47 is the illustration showing the structure of the wideband antenna 1200 regarding the eleventh embodiment of the invention. The same parts as those of FIG. 39 are referred to the same reference numerals, and detailed explanation thereof will be omitted.
As shown in FIG. 47, the antenna 1200 comprises a conductive element 35 and a conductive element 36. These elements 35, 36 are mounted on a dielectric substrate however, the substrate is not shown.
The elements 35, 36 are thin plates made of conductive material. The element 35 has a basic shape of the element 31 of the tenth embodiment. The element 35 forms a notch 37 so as to divide the side 31a of the element 31 into two of a side 31a-1 and a side 31a-2. The element 36 has a basic shape of the element 32 of the tenth embodiment. The element 36 forms a notch 38 so as to divide the side 32a of the element 32 into two of a side 32a-1 and a side 32a-2. Positions to form the notches 37, 38 are within a rage of λ3×¼ from the tops 31e, 32e. Here, λ3 indicates a wavelength at an upper limit frequency in the required frequency band. The shapes of the notches 37, 38 may be determined arbitrarily.
FIGS. 48A, 48B are illustrations explaining functions of the notches 37, 38.
FIG. 48A shows a current distribution of the upper limit frequency in the antenna 1100 of the tenth embodiment. Currents through the peripheral edges of the elements 31, 32 contribute on a large scale. Through the side 31c of the element 31, a current I1 flows in approximately one direction over the whole of the side 31c. Although through the side 31a, a current I2 with the same phase as that of the current I1 flows on a side apart from the top 31e, a current I3 with inverted phase to the current I1, I2 flows on a side near the top 31e. Radiation toward the side 31a of the antenna 100 is reduced due to the influence of the inverted current I3. This phenomenon symmetrically occurs in the element 32 and reduces the radiation toward the side of the side 32a.
As shown in FIG. 48B, in the element 35 of the antenna 1200, the direction of the current I3 through the notch 37 varies and vertical components (vertical components in FIGS. 48A, 48B) of the current I3 decrease. Thus, current components inverted to the current I2 decrease and the current I2 efficiently generates radiation. That is, the radiation toward sides of the sides 31a-1 and 31a-2 increases in comparison with that of the antenna 1100. The radiation from the element 36 toward sides of the sides 32a-1 and 32a-2 similarly increases in comparison with that of the antenna 1100.
FIGS. 49A to 49F are illustrations showing degree of improvements of radiation patterns from the antenna 1200.
By a simulation destined to a model shown in FIGS. 49A-49C, the characteristics shown in FIGS. 49D-49F are obtained. FIG. 49A, FIG. 49B and FIG. 49C show the respective models respectively simulating the antenna 1100, the antenna 1200 and a wideband antenna in which positions of the notches 37, 38 of the antenna 1200 are changed. The wideband antenna simulated by the model in FIG. 49C forms notches outside the range λ3×¼ from the tops 31e, 32e.
As clarified in comparison with each FIG. 49D-49F, the radiation patterns of the antenna 1200 show the best balance. In particular, the radiation characteristics of the antenna 1200 are more improved at the part surrounded with circle C2 than at the parts surrounded with circles C1 and C3.
The reason why the model in FIG. 49C does not improve the radiation pattern results from incompletion of the actions described above though the notch has been formed outside the range λ3×¼ from the tops 31e, 32e due to the fact that the current I3 is mainly generated within the range.
FIG. 50 is the illustration showing the characteristics of the VSWR and the reflection coefficient of the antenna 1200. FIG. 51 is the Smith chart with respect to the antenna 1200. FIGS. 52A to 52G are the illustrations showing radiation patterns of the antenna 1200. FIGS. 52B to 52D show radiation patterns on an XY plane of a coordinate system shown in FIG. 52A, and FIGS. 52E to 52G show radiation patterns on an XZ plane of the coordinate system shown in FIG. 52A. Moreover, FIG. 52B and FIG. 52E show radiation patterns at 3 GHz, FIG. 52C and FIG. 52F show radiation patterns at 5 GHz, and FIG. 52D and FIG. 52G show radiation patterns at 8 GHz.
As known from these FIG. 50 to FIG. 52, the antenna 1200 can obtain radiation patterns further excellent in balance in the whole range of the wide transmittable/receivable band by being provided with the notches 37, 38.
Twelfth Embodiment
FIG. 53 is the illustration showing the structure of the wideband antenna 1300 regarding the twelfth embodiment in the invention. The same parts as those of FIG. 39 are referred to by the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 53, the antenna 1300 comprises a conductive element 39 and a conductive element 40. These elements 39, 40 are mounted on a dielectric substrate however, the substrate is not shown.
The elements 39, 40 are thin plates made of conductive material. Each element 39, 40 are shaped as a trapezoid in which only one side is inclined. The elements 39, 40 are approximately symmetric in shape with each other.
As shown in FIG. 53, four sides of the element 39 are referred to as sides 39a, 39b, 39c and 39d. The side 39b is the inclined side as described above. The sides 39a, 39c contact opposed ends of the side 39b. The sides 39a, 39c are approximately parallel to each other. A top 39e is formed at a section with which the sides 39a, 39b are contacted. The opposed sides of the side 39d contact the sides 39a and 39c.
As shown in FIG. 53, four sides of the element 40 are referred to as sides 40a, 40b, 40c and 40d. The sides 40a, 40c contact opposed ends of the side 40b. The sides 40a, 40c are approximately parallel to each other. A top 40e is formed at a section with which the sides 40a, 40b are contacted. The opposed ends of the side 40d contact the sides 40a and 40c.
The elements 39, 40 are mounted on the dielectric substrate in a state that the tops 39e, 40e are opposed to each other. A small gap is provided between the tops 39e and the 40e. The sides 39a, 40a and the sides 39c, 40c are respectively positioned on the respective same straight line.
By such arrangements of the elements 39, 40 described above, the notch 34 is formed between the elements 39 and 40.
Sizes of the elements 39, 40 are determined in consideration of the required frequency band. That is, a length from an end of the side 39c up to an end of the side 40c along with the sides 39c, 39b, 40b and 40c is defined in the same manner for the length L11 of the antenna 100. A length from an end of the side 39b up to an end of the side 40b along with the sides 39b, 40b is defined in the same manner for the length L12 of the antenna 1100.
The antenna 1300 structured as described above, determines a point between a section near the top 39e and a section near the top 39e as a power feeding point.
FIG. 54 is the illustration showing the characteristics of the VSWR and the reflection coefficient of the antenna 1300. FIG. 55 is the Smith chart with respect to the antenna 1300.
As known from these FIG. 54 and FIG. 55, also the antenna 1300 as well as the antenna 1100 can obtain a wide transmittable/receivable band by the combination of two resonant frequencies in the same manner as that of the antenna 1100.
Moreover, the antenna 1300 can be easily shaped in response to a housing space of a communication apparatus, etc.
Thirteenth Embodiment
FIG. 56 is the perspective view showing the structure of the wideband antenna 1400 regarding the thirteenth embodiment of the invention. In FIG. 56, the same parts as those of the FIG. 39 are referred to the same reference numerals and detailed explanation thereof will be omitted.
As shown in FIG. 56, the antenna 1400 comprises the conductive elements 31, 32 and a dielectric substrate 41.
The substrate 41 is shaped so that the dielectric substrate 33 is squarely bent at its center section. Hereinafter, two parts of the substrate 41 different in direction are referred to as a vertical section 41a and a horizontal section 41b, respectively.
The elements 31, 32 are attached to the vertical section 41a and the horizontal section 41b of the substrate 41, respectively, in a state that the top 31e and the top 32e are opposite to each other. A small gap is provided between the top 31e and the top 32e. The sides 31a and 32a are respectively positioned on two straight lines intersecting orthogonally with each other and the sides 31c and 32c are respectively positioned on another two straight lines intersecting orthogonally with each other.
By such arrangements of the elements 31, 32, a notch 42 is formed between the side 31b and the side 32b and also between the elements 31 and 32. The width of the notch 42 becomes narrowest between the tops 31e and 32e and becomes gradually wider with getting apart from the tops 31e, 32e.
Even in the antenna 1400 with the structure described above, resonant points are defined in the same manner as that of the antenna 1100.
FIG. 57 is the illustration showing the characteristics of the VSWR and the reflection coefficient of the antenna 1400. FIG. 58 is the Smith chart with respect to the antenna 1400.
As is known from FIGS. 57, 58, also the antenna 1400 as well as the antenna 1100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
FIGS. 59A to 59G are illustrations showing radiation patterns of the antenna 1400. FIGS. 59B-59D show horizontally polarized waves on an XY plane of a coordinate system shown in FIG. 59A, and FIGS. 59E-59G show vertically polarized waves on the XY plane of the coordinate system shown in FIG. 59A. Moreover, FIG. 59B and FIG. 59E show a radiation pattern at 3 GHz, FIG. 59C and FIG. 59F show a radiation pattern at 5 GHz, and FIG. 59D and FIG. 59G show a radiation pattern at 7 GHZ.
As known from these FIGS. 59A to 59G, the antenna 1400 has excellent radiation patterns in both horizontally and vertically polarized waves.
Fourteenth Embodiment
FIG. 60 is the perspective view showing the structure of the wideband antenna 1500 regarding the fourteenth embodiment of the invention. The same parts as those of FIG. 39 are referred to the same reference numerals and detail thereof will be omitted.
As shown in FIG. 60, the antenna 1500 comprises the conductive elements 31, 32 and a dielectric substrate 43.
The substrate 43 is a thin plate made of a dielectric and formed in L-shape.
The elements 31, 32 are attached to the same surface of the substrate 43 in a state that the top 31e and the top 32e are opposite to each other. In this case, the tops 31e, 32e are positioned close to corner sections of outer sides formed by the L-shape of the substrate 43. Each side 31a and 32a respectively takes along two sides of the outer sides formed by the L-shape of the substrate 43. Each side 31c and 32c takes along two sides of inner sides formed by the L-shape of the substrate 43. An angle formed by the tops 31e, 32e is smaller than 45°.
By such arrangements of the elements 31 and 32, a notch 44 is formed between the elements 31 and 32. A width of the notch 44 is narrowest between the tops 31e and 32e, and gradually becomes wider with getting apart from the tops 31e, 32e. That is, the notch 44 is shaped so that an intermediate point between the tops 31e and 32e is set as a reference point and the width becomes wider with getting apart from the reference point. Sizes of the elements 31, 32 are defined in the same manner as that of the tenth embodiment. Gradients of the sides 31b 32b are made wider than those of the tenth embodiment.
In the antenna 1500 having such a structure, resonant points are also defined in the same manner as that of the antenna 1100.
FIG. 61 is the illustration showing the characteristics of the VSWR of the antenna 1500.
As is known from FIG. 61, also the antenna 1500 as well as the antenna 1100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
FIG. 62 is the illustration showing the radiation pattern of the antenna 1500, and shows a radiation pattern at 3 GHz with respect to the XY plane of the coordinate system shown in FIG. 60.
As known from FIG. 62, the antenna 1500 can obtain excellent radiation patterns in respect to both horizontally and vertically polarized waves.
Furthermore, although the antenna 1500 can radiate such both polarized waves, it can be housed in a thin space. Whereby, the antenna 1500 is suitable for being mounted on a communication apparatus having low-profile housing such as a cellular phone.
The fourteenth embodiment can be achieved with modification as the wideband antenna 1550 shown in FIG. 63.
The elements 31, 32 of the antenna 1550 varies angles formed by the tops 31e, 32e to an extent not smaller than 45°. Then, the tops 31f, 32f positioned near the corner sections of the inner sides formed by L-shape of the substrate 43 are opposite to each other. A small gap is provided between the tops 31f and 32f.
By such arrangements of the elements 31, 32, a notch 44′ is formed between the elements 31 and 32. A width of the notch 44′ becomes narrowest between the tops 31f and 32f and gradually becomes wider with getting apart from the tops 31f, 32f. That is, the notch 44′ sets an intermediate point between the tops 31f and 32f to a reference point and has a shape so that the width becomes wider with getting apart from the reference point.
Fifteenth Embodiment
FIG. 64 is the perspective view showing the structure of the wideband antenna 1600 regarding the fifteenth embodiment of the invention.
As shown in FIG. 64, the antenna 1600 comprises conductive elements 45, 46. Each element 45, 46 is formed in a shape in which a pentagonal thin plate made of conductive material is approximately squarely bent.
As shown in FIG. 64, sides of the element 45 are referred to as sides 45a, 45b, 45c, 45d, 45e and 45f, respectively. The sides 45b, 45c contact with each other. The side 45a contacts the side 45b at an end on a side of the side 45b with which the side 45c is not contacted. The side 45d contacts side 45c at an end on a side of the side 45c with which the side 45b is not contacted. The side 45e almost squarely contacts side 45d at an end on a side of the side 45d with which the side 45c is not contacted. The side 45f approximately squarely contacts side 45e at an end on a side of the side 45a with which the side 45b is not contacted. A bending line of the element 45 passes through a contact point between the sides 45b and 45c and a contact point between the sides 45e and 45f. Sides 45a, 45b and 45f are positioned on the same surface. Sides 45c, 45d and 45e are positioned on the same surface. The surface with the sides 45a, 45b and 45f positioned thereon and the surface with the sides 45c, 45d and 45e positioned thereon are brought into mutually almost orthogonal states.
As shown in FIG. 64, sides of the element 46 are referred to as sides 46a, 46b, 46c, 46d, 46e and 46f, respectively. The sides 46b, 46c contact with each other. The side 46a contacts the side 46b at an end on a side of the side 46b with which the side 46c is not contacted. The side 46d contacts side 46c at an end of on a side the side 46c with which the side 46b is not contacted. The side 46e almost squarely contacts side 46d at an end on a side of the side 46d with which the side 46c is not contacted. The side 46f almost squarely contacts side 46e at an end on a side of the side 46e with which the side 46d is not contacted. The side 46f almost squarely contacts side 46a at an end on a side of the side 46a with which the side 46b is not contacted. A bending line of the element 46 passes through a contact point between the sides 46b and 46c, and a contact point between the sides 46e and 46f. Sides 46a, 46b and 46f are positioned on the same surface. Sides 46c, 46d and 46e are positioned on the same surface. The surface with the sides 46a, 46b and 46f positioned thereon and the surface with the sides 46c, 46d and 46e positioned thereon are intersected almost orthogonally with each other.
In the elements 45 and 46, a top 45g and a top 46g face each other across a small gap, and the side 45a and the side 46a are respectively positioned on two straight lines intersecting almost orthogonally each other, and also the side 45d and the side 46d are respectively positioned on two straight lines intersecting almost orthogonally each other. The top 45g is formed at the contact point between the side 45a and the side 45b. The top 46g is formed at the contact point between the side 46a and the side 46b.
Thus, if a coordinate system is defined as shown in FIG. 64, every side 45a, 45b, 45e, 45f, 46a, 46b, 46f is positioned on a YZ plane. Every side 45c, 45d, 45e is positioned on an XY plane. Every side 46c, 46d, 46e is positioned on a ZX plane.
According to such arrangements of the elements 45, 46, a notch 48 is formed between the side 45b and the side 46b and between the side 45c and the side 46c. The side 45b, 45c, 46b and 46c are inclined so that the width of the notch 48 becomes narrowest between the tops 45g and 46g and becomes gradually wider with getting apart from the tops 45g, 46g. Thus, the notch 48 sets an intermediate point between the tops 45g and 46g as a reference point, and the notch 48 has a shape so that the width thereof becomes wider with getting apart from the reference point.
The elements 45, 46 are mounted on a dielectric substrate 47 in the state mentioned above.
Sizes of the elements 45, 46 are defined in consideration with wavelengths λ1, λ2 in the same manner that of the tenth embodiment. That is, a length L3 from a contact point between the sides 45d and 45e up to a contact point between the sides 46d and 46e along with the sides 45d, 45c, 45b, 46b 46c, and 46d is set to approximately λ1×½. A length L4 from a contact point between the sides 45c and 45d up to a contact point between the sides 46c and 46d along with the sides 45c, 45b, 46b and 46c is set to approximately λ2×½. The length L3 is ideally set to λ1×½, i.e. λ1×0.5, however, extent from λ1×0.4 to λ1×10.6 may be sufficient. The length L4 is ideally set to λ2×½, i.e. λ2×0.5, however, an extent from λ2×0.4 to λ2×0.6 may be sufficient.
The antenna 1600 structured as mentioned above defines a point as a power feeding point between a section near the top 45g and a section near the top 16g.
Also in the antenna 1600 having such a structure mentioned above, resonant points are defined in the same manner as that of the antenna 1100.
FIG. 65 is the illustration showing the characteristics of the VSWR of the antenna 1600.
As is known from FIG. 65, also the antenna 1600 as well as the antenna 1100 can offers a wide transmittable/receivable band by a combination of two resonant frequencies.
FIGS. 66A to 66F are illustrations showing radiation patterns of the antenna 1600. FIGS. 66A to 66C show radiation patterns on XY planes of a coordinate system in FIG. 64, and FIGS. 66D to 66F show radiation patterns on ZX planes of the coordinate system shown in FIG. 64. Moreover, FIG. 66A and FIG. 66D show a radiation pattern at 3 GHz, FIG. 66B and FIG. 66E show a radiation pattern at 5 GHz, and FIG. 66C and FIG. 66F show a radiation pattern at 7 GHZ.
As known from these FIGS. 66A to 66F, the antenna 1600 can obtain excellent radiation patterns in both horizontally and vertically polarized waves.
Sixteenth Embodiment
FIG. 67 is the illustration showing the structure of the communication apparatus regarding the sixteenth embodiment of the invention.
The communication apparatus is composed by housing component elements such as a variety of electric parts into a housing 49 having an approximately rectangular shape. As for an antenna to transmit and receive a radio signal, any one of the antennas 1400, 1500, 1550 and 1600 described above is mounted on the communication apparatus. Each antenna 1400, 1500, 1550 and 1600 has a shape so that two conductive elements make the respective corner sections as mentioned above. Then, the respective antennas 1400, 1500, 1550 and 1600 are disposed into the housing 49 so that the respective corner sections made by two elements to be taken along with the corner sections of the housing 49.
Consequently, any one of the antennas 1400, 1500, 1550 and 1600 can be efficiently housed into the housing 49, a flexibility of housing of other component elements can be improved and the housing 49 can be miniaturized.
Seventeenth Embodiment
FIGS. 68A, 68B are the illustrations showing the communication apparatus regarding the seventeenth embodiment of the invention.
The communication apparatus is composed by housing component elements such as a variety of electric parts into an upper housing 50 and a lower housing 51 respectively having approximately rectangular shapes. As for an antenna to transmit and receive a radio signal, any one of the wideband antennas 1400, 1500 and 1600 is mounted on the communication apparatus.
In this kind of communication apparatus, a display device 52 is often housed in the upper housing 50. Almost all of an inner space of the upper housing 50 is used as a housing space for the display device 52. At the same time, some of spaces are often remain at corner sections of the upper housing 50. On the other hand, the antennas 1400, 1500, 1550 and 1600 are shaped so that two conductive elements respectively make corner sections as described above. The antennas 1400, 1500, 1550 and 1600 are arranged inside the housing 49 of the sixteenth embodiment by making the corner section formed by the two elements run along the corner sections of the upper housing 50.
FIG. 68A shows an example in which any one of the antennas 1400, 1500, 1550 and 1600 is housed in a corner section on the upper-left of the upper housing 50. FIG. 68B shows an example in which any one of the antennas 1400, 1500, 1550 and 1600 is housed in any one of the four corner sections, respectively.
Accordingly, the communication apparatus can efficiently house the antennas 1400, 1500, 1550 and 1600 in the upper housing 50.
Each embodiment described above can be achieved in a variety of modified embodiments.
In each embodiment, conductive elements can be also achieved as conductive patterns formed on the dielectric substrates. For example, as shown in FIG. 69, the antenna 100 consisting of conductive patterns can be produced by peeling off a masking 26 from a substrate 25 after spraying a conductive plating film onto the substrate 25 in a state that the masking 26 is stuck on the substrate 25.
In each embodiment, a supporting member to support the conductive element may be a frame-like member to surround the conductive element.
In each embodiment, two elements may be held at the positional relationship of each embodiment by the supporting member with an arm-like shape, etc. different from that of the dielectric substrate.
In the case that a conductive element with a bent-shape is used as the seventh embodiment or the eighth embodiment, the bending angle is not limited to a right-angle and may be an arbitrary angle. Or, the element may be curved to a curved surface. For example, the eighth embodiment may be modified so that the element is formed in a cylindrical shape.
In the eleventh embodiment, either the notch 37 or the notch 38 may be eliminated.
In the thirteenth embodiment, the face with the element 31 mounted thereon and the face with the element 32 mounted thereon may be intersected with inclination.
In the fourteenth embodiment, the straight line with the side 31a positioned thereon and the straight line with the side 32a positioned thereon may be intersected with inclination.
In the fifteenth embodiment, the straight line with the side 45a positioned thereon and the straight line with the side 46a positioned thereon may be intersected with inclination.
In the fifteenth embodiment, the face with the side 45b positioned thereon and the face with the side 45c positioned thereon may be intersected with inclination.
In the fifteenth embodiment, the face with the side 46b positioned thereon and the face with the side 46c positioned thereon may be intersected with inclination.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Patent Application
20060017643
