The present disclosure relates to an antenna device.
PTL 1 discloses an antenna device including an antenna for a low frequency band and an antenna for a high frequency band.
The low frequency band of the telephone antenna of PTL1 has a narrow bandwidth in particular, and thus it is difficult for the antenna device to support radio waves in a wide frequency band from low to high frequencies.
An example of an object of the present disclosure is to implement an antenna device capable of supporting radio waves in a wide frequency band. Other objects of the present disclosure will be apparent from the description of this specification.
An aspect of the present disclosure is an antenna device comprising: a first element; a second element capacitively coupled to the first element; and a base portion coupled to the first element and the second element, wherein the first element supports, with the second element, radio waves at least in a first frequency band.
According to an aspect of the present disclosure, it is possible to implement an antenna device capable of supporting radio waves in a wide frequency band.
At least following matters will become apparent from the descriptions of the present specification and the accompanying drawings.
Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. Elements, members, and the like that are the same or equivalent in the drawings will be given the same reference signs, and a description thereof is omitted as appropriate.
First, directions (left-right direction, front-rear direction, up-down direction) and the like in the antenna device 1A are defined with reference to
In
In
In
The front-rear direction may be referred to as X direction; the left-right direction may be referred to as Y direction; and the up-down direction may be referred to as Z direction. As illustrated in
The aforementioned definition of the directions and the like also apply to other embodiments of this specification unless otherwise specified.
Next, the overview of the antenna device 1A of the first embodiment is described with reference to
The antenna device 1A is a vehicle antenna device to be used in a vehicle (not illustrated). In an embodiment according to the present disclosure, the antenna device 1A is mounted at the roof of the vehicle or inside the instrument panel of the vehicle, for example. The antenna device 1A may be positioned at any portion of the vehicle other than the roof of the vehicle or the inside of the instrument panel of the vehicle, such as a spoiler or an overhead console of the vehicle. The antenna device 1A may be an antenna device for those other than vehicles.
The antenna device 1A includes the case 2, the ground portion 3, an antenna 10A, an antenna 20A, a base portion 30A, and a filter 40, which is illustrated in
The case 2 is a member forming the upper face of the antenna device 1A. In an embodiment of the present disclosure, the case 2 is made of insulating resin, for example. However, the case 2 may be made of another material that is other than an insulating resin material and that allows radio waves to pass therethrough. The case 2 may include a part made of insulating resin and a part made of another material allowing radio waves to pass therethrough, and may include any combination of such members.
The case 2 is fixed to the ground portion 3 with plural screws (not illustrated). However, the case 2 is not limited to being fixed with screws and may be fixed to the ground portion 3 by snap fitting, welding, adhesion, and/or the like. In this case, the antenna 10A, antenna 20A, base portion 30A, and filter 40 are arranged in a housing space defined by the case 2 forming the upper face of the antenna device 1A, and the ground portion 3 forming the bottom face of the antenna device 1A.
The case 2 may be fixed to a member other than the ground portion 3. For example, the case 2 may be fixed to a base (not illustrated) that is a member other than the ground portion 3. The base is made of insulating resin, for example. However, the base may be made of another material that is other than an insulating resin material and that allows radio waves to pass therethrough. In addition, the base may include a part made of insulating resin and a part made of another material allowing radio waves to pass therethrough, and may include any combination of such members. The ground portion 3, antenna 10A, antenna 20A, base portion 30A, and filter 40 may be arranged in a housing space defined by the case 2 forming the upper face of the antenna device 1A, and the base forming the bottom face of the antenna device 1A.
The ground portion 3 is a member serving as a ground for antennas (the antennas 10A and 20A herein) included in the antenna device 1A. In the embodiment of the present disclosure, the ground portion 3 serves as the ground common to the antennas 10A and 20A. However, the ground portion 3 may serve as a ground for a part of the antennas included in the antenna device 1A. For example, the ground portion 3 may serve as a ground for the antenna 10A while another ground portion may serve as a ground for the antenna 20A.
In the embodiment of the present disclosure, the ground portion 3 is formed of a single metal plate (sheet metal) as illustrated in
The ground portion 3 may be formed of a member other than a plate-shaped one as long as the ground portion 3 serves as a ground for antennas included in the antenna device 1A. The ground portion 3 may include any combination of a member made of metal and a member made of a material other than metal, as long as the ground portion 3 serves as a ground for antennas included in the antenna device 1A. For example, the ground portion 3 may include a metal plate and a resin insulator. Further, the ground portion 3 may be formed of a single substrate including a printed-circuit board (PCB) with a conductor pattern formed therein.
As illustrated in
In the embodiment of the present disclosure, the ground portion 3 includes seat portions 4, which support the base portion 30A. The seat portions 4 are formed so as to protrude upward by bending a part of the ground portion 3. The base portion 30A is provided on the upper side of the seat portions 4. Accordingly, the base portion 30A is positioned above the front surface (the surface in the +Z direction) of the ground portion 3 with a predetermined distance therebetween.
Note that the base portion 30A may be supported by a holder (not-illustrated) or the case 2, for example, as long as the base portion 30A is positioned above the front surface of the ground portion 3 with a predetermined distance therebetween. In this case, the ground portion 3 does not have to include the seat portions 4. When the base portion 30A is supported by the case 2, an antenna element, such as a first element 11A, for example, which will be described later, may be fixed to the base portion 30A with solder or an M-shaped spring. The base portion 30A may be directly provided at the front surface of the ground portion 3 without the seat portions 4 provided therebetween. In other words, the base portion 30A may be positioned at the front surface of the ground portion 3 without any space therebetween.
The antenna 10A is a broadband antenna for mobile communication based on an inverted-F antenna. In the embodiment of the present disclosure, the antenna 10A supports radio waves in a frequency band of 699 to 5000 MHz for GSM, UMTS, LTE, and 5G, for example. However, the antenna 10A is not limited to this, and may support radio waves in a frequency band for a part (e.g., only 5G) of GSM, UMTS, LTE, and 5G.
Further, the antenna 10A may support radio waves in a frequency band other than the frequency band for GSM, UMTS, LTE, and 5G. For example, the antenna 10A may be an antenna supporting radio waves in a frequency band used for telematics, V2X (Vehicle to Everything: vehicle-to-vehicle communication, vehicle-to-road communication), Wi-Fi, Bluetooth, and/or the like. Furthermore, the antenna 10A may support MIMO (Multiple-Input Multiple-Output) communication, as will be described later.
In the following description, a predetermined range of low frequencies in the frequency band of radio waves supported by the antenna 10A may be referred to as “low-frequency band”. In the embodiment of the present disclosure, the low-frequency band is in a range of 699 to 960 MHz, for example.
A predetermined range of high frequencies in the frequency band of radio waves supported by the antenna 10A may be referred to as “high-frequency band”. In the embodiment of the present disclosure, the high-frequency band is in a range of 3300 to 5000 MHz, for example.
A predetermined range of frequencies between the low- and high-frequency bands in the frequency band of radio waves supported by the antenna 10A may be referred to as “mid-frequency band”. In the embodiment of the present disclosure, the mid-frequency band is in a range of 1710 to 2690 MHz, for example.
As described above, the low-frequency band is a frequency band lower than the mid-frequency band. The mid-frequency band is a frequency band higher than the low-frequency band and lower than the high-frequency band. The high-frequency band is a frequency band higher than the mid-frequency band.
Note that the mid-frequency and high-frequency bands may be collectively referred to as “mid/high frequency band”. The frequency values given in the aforementioned low-frequency, mid-frequency, and high-frequency bands are not limited to those values, and may be varied depending on the frequency band of radio waves supported by the antenna 10A.
The antenna 10A includes the first element 11A and a feed portion 18.
The first element 11A is an element that resonates in the frequency band (e.g., the low-frequency band and the mid/high frequency band) of radio waves supported by the antenna 10A. The first element 11A is coupled to the base portion 30A as illustrated in
The first element 11A includes the standing portion 12A, the extending portion 13A, and a short-circuit portion 17A.
The standing portion 12A is a portion of the first element 11A and is formed so as to stand against the base portion 30A. In the embodiment of the present disclosure, the standing portion 12A is formed so as to stand in the up direction against the base portion 30A. The direction in which the standing portion 12A stands against the base portion 30A is not limited to the up direction (the +Z direction), but may be inclined at a predetermined angle relative to the base portion 30A.
In the embodiment of the present disclosure, the standing portion 12A has a self-similar shape as illustrated in FIG. 2B. This can implement a wider frequency band. Herein, the self-similar shape is a shape that is similar to itself even when the scale (size ratio) changes. However, the standing portion 12A does not have to have a self-similar shape.
At the end portion of the standing portion 12A in the down direction (the −Z direction), a first element coupling portion 19 is provided as illustrated in
The first element 11A may be coupled to the base portion 30A by screwing depending on the frequency band supported by the first element 11A. In this case, bosses for screwing are formed in the case 2, and the first element 11A is screwed to the case 2 together with the base portion 30A, thereby making it possible to both mechanically support the first element 11A and electrically couple the first element 11A and the base portion 30A. Further, in this case, the screws can act as a part of the antenna with the length of the screws being adjusted.
The extending portion 13A is a portion formed so as to extend from the standing portion 12A. The extending portion 13A is also the portion formed so as to face the ground portion 3. In the embodiment of the present disclosure, the extending portion 13A is formed so as to extend from the upper end portion of the standing portion 12A, as illustrated in
The extending portion 13A includes a main portion 14A, a first additional portion 15A, and a second additional portion 16A.
The main portion 14A is a portion of the extending portion 13A and extends from the standing portion 12A. In
The first additional portion 15A is a portion that extends from the main portion 14A and is positioned away from the standing portion 12A. In the embodiment of the present disclosure, the first additional portion 15A extends rearward from the rear end portion of the main portion 14A, bends to the right direction, and further extends. In
The second additional portion 16A is a portion that extends from the main portion 14A and is positioned close to the standing portion 12A. In
The short-circuit portion 17A is a portion that branches off from the extending portion 13A and is coupled to the base portion 30A. The short-circuit portion 17A is electrically coupled to the ground portion 3. Since the first element 11A includes the short-circuit portion 17A, it is possible to facilitate impedance matching in the frequency band of radio waves supported by the antenna 10A.
The short-circuit portion 17A may be coupled to the base portion 30A by soldering, welding, and the like, or by screwing. In this case, a boss for screwing is formed in the case 2, and the short-circuit portion 17A is screwed to the case 2 together with the base portion 30A, thereby making it possible to both mechanically support the short-circuit portion 17A and electrically couple the short-circuit portion 17A and the base portion 30A. Further, in this case, the screws can act as a part of the antenna by adjusting the length of the screw.
The antenna 10A according to the embodiment of the present disclosure mainly supports the low-frequency band with the standing portion 12A, the main portion 14A, the first additional portion 15A, and the short-circuit portion 17A. In other words, the portion constituted by the standing portion 12A, main portion 14A, first additional portion 15A, and short-circuit portion 17A in the first element 11A is formed to have a length and a width corresponding to a wavelength used in the low-frequency band (e.g., the wavelength at 699 MHz).
Further, the antenna 10A according to the embodiment of the present disclosure mainly supports the mid-frequency band with the standing portion 12A, the main portion 14A, the second additional portion 16A, and the short-circuit portion 17A. In other words, the portion constituted by the standing portion 12A, main portion 14A, second additional portion 16A, and short-circuit portion 17A in the first element 11A is formed to have a length and a width corresponding to a wavelength used in the mid-frequency band (e.g., the wavelength at 2 GHz).
Further, the antenna 10A according to the embodiment of the present disclosure mainly supports the high-frequency band mainly with the standing portion 12A. In other words, the portion constituted by the standing portion 12A in the first element 11A is formed to have a length and a width corresponding to a wavelength used in the high-frequency band (e.g., the wavelength at 5 GHz).
The feed portion 18 is a region including the feed point of the antenna 10A. In the embodiment of the present disclosure, the feed portion 18 is positioned in a portion (the first element coupling portion 19) that couples the first element 11A and the base portion 30A, as illustrated in
The antenna 20A is a broadband antenna for mobile communication based on a monopole antenna. In the embodiment of the present disclosure, the antenna 20A supports radio waves in a frequency band different from the frequency band of radio waves supported by the antenna 10A. The antenna 20A supports radio waves in the frequency band of 1710 to 5000 MHz for Sub-6 GHz, for example. However, the antenna 20A may support radio waves in a frequency band other than that of Sub-6 GHz. For example, the antenna 20A may be an antenna supporting radio waves in a frequency band used in telematics, V2X, Wi-Fi, Bluetooth, and/or the like.
The antenna 20A may support radio waves in the same frequency band as that of radio waves supported by the antenna 10A. In other words, the antenna 20A may support radio waves in the frequency band of 699 to 5000 MHz for GSM, UMTS, LTE, and 5G, for example. In this case, the antenna device 1A may be an antenna device for MIMO communication, for example. In MIMO communication, plural antennas individually transmit data and receive data simultaneously. The antenna device 1A that performs MIMO communication individually transmits data through the antennas 10A and 20A, which constitute the antenna device 1A, and receives data simultaneously through the antennas 10A and 20A.
The antenna 20A includes the second element 21A and a feed portion 27. The second element 21A includes an antenna portion 22 and an additional element portion 23.
The antenna portion 22 is an element that resonates in a frequency band (e.g., 1710 to 5000 MHz band for Sub-6 GHz) of radio waves supported by the antenna 20A. The antenna portion 22 is formed so as to have a length and a width corresponding to the frequency band (1710 to 5000 MHz band for Sub-6 GHz, herein) of radio waves supported by the antenna 20A.
The antenna portion 22 includes a standing portion 24 and an extending portion 25, similarly to the standing portion 12A and extending portion 13A in the aforementioned first element 11A.
The standing portion 24 is a portion of the antenna portion 22 and is formed so as to stand against the base portion 30A. In the embodiment of the present disclosure, the standing portion 24 is formed so as to stand upward against the base portion 30A. Note that the direction in which the standing portion 24 stands against the base portion 30A is not limited to the up direction (the +Z direction), but may be a direction inclined at a predetermined angle relative to the base portion 30A.
As illustrated in
The extending portion 25 is a portion formed so as to extend from the standing portion 24. The extending portion 25 is also the portion formed so as to face the ground portion 3. In the embodiment of the present disclosure, the extending portion 25 is formed so as to extend from the upper end portion of the standing portion 24, as illustrated in
The additional element portion 23 is a portion formed so as to further extend from the extending portion 25 of the antenna portion 22. The additional element portion 23 is a portion that resonates with the antenna portion 22, in the frequency band (e.g., 1710 to 5000 MHz band for Sub-6 GHz) supported by the antenna 20A. The additional element portion 23 includes a portion capacitively coupled to the first element 11A.
Specifically, the additional element portion 23 extends in the +X direction from the extending portion 25 of the antenna portion 22, as illustrated in
Herein, when the end portion of the additional element portion 23 is adjacent to the end portion of the first element 11A, the “end portion” does not refer to an exact end, but refers to a predetermined region including the end.
In the embodiment of the present disclosure, the end portions of the additional element portion 23 and first additional portion 15A are positioned so as to overlap in the plan view illustrated in
In the embodiment of the present disclosure, the end portion of the first additional portion 15A is positioned above the end portion of the additional element portion 23, as illustrated in
Further, the end portions of the additional element portion 23 and first additional portion 15A may be spaced apart from each other in the left-right direction in the plan view illustrated in
Furthermore, in the embodiment of the present disclosure, the end portions of the additional element portion 23 and first additional portion 15A are at the same position in the front-rear direction as illustrated in
From the above, the end portions of the additional element portion 23 and first additional portion 15A just have to be provided adjacent to each other such that the first element 11A and second element 21A are capacitively coupled to each other.
In the antenna device 1A of the embodiment of the present disclosure, as described above, the end portions of the first and second elements 11A and 21A are positioned so as to be capacitively coupled to each other, to thereby implement a capacitive coupling portion 35.
This makes it possible to generate two resonances in the low-frequency band, with the first element 11A of the antenna 10A and the second element 21A of the antenna 20A, which includes the additional element portion 23. In other words, with superposition of the two resonances, which are the resonance of the first element 11A of the antenna 10A alone and the resonance of the antenna 10A considering capacitive coupling, it is possible to expand the band corresponding to the low-frequency band supported by the first element 11A toward the lower frequency side. Accordingly, the antenna 10A of the antenna device 1A according to the embodiment of the present disclosure can easily achieve a wider frequency band.
The feed portion 27 is a region including the feed point of the antenna 20A. In the embodiment of the present disclosure, the feed portion 27 is positioned in the portion (the second element coupling portion 26) coupling the second element 21A and the base portion 30A, as illustrated in
The base portion 30A is a plate member that is coupled to the first element 11A of the antenna 10A and the second element 21A of the antenna 20A. The base portion 30A may be provided with elements, circuits, and/or the like to process signals from the antennas 10A and 20A.
In the antenna device 1A according to the embodiment of the present disclosure, the base portion 30A is a printed circuit board (PCB), for example. The base portion 30A is formed such that a conductor pattern formed in a resin material such as glass epoxy resin, for example. However, the base portion 30A may be formed such that a conductor pattern is formed in a resin material other than glass epoxy resin, such as phenol resin. Further, the base portion 30A may be a flexible substrate, for example.
The base portion 30A does not have to be entirely plate-shaped. The base portion 30A may include a part having a shape other than a plate shape. For example, the base portion 30A may be a part of the case 2 or may be a part of the holder (not illustrated) holding the first element 11A and the second element 21A described above. In this case, the case 2 and the holder (not illustrated) may be made of resin, for example.
The base portion 30A is not limited to the aforementioned configuration, but may be configured only with a conductor pattern. When the base portion 30A is configured such that a conductor pattern is formed in a resin material, the MID (Molded Interconnect Device) technology can be used, for example. This makes it possible to form a conductor pattern in a resin material having a complicated three-dimensional shape. It is also possible to form a conductor pattern, with the use of the MID technology, in a resin material having a shape as of the base portion 30A illustrated in
When the antennas 10A and 20A are arranged adjacent to each other so as to be capacitively coupled as described above as in the antenna device 1A according to the embodiment of the present disclosure, isolation between the antennas 10A and 20A may deteriorate. Specifically, when the antennas 10A and 20A are arranged adjacent to each other, the antenna 10A may be affected by signals in the frequency band supported by the antenna 20A, and vice versa. For example, signals at a frequency of radio waves supported by the antenna 10A may travel to the base portion 30A side through the feed portion 27 of the antenna 20A. Thus, the antenna 10A is affected by the antenna 20A, which is arranged adjacent to the antenna 10A, and the characteristics in the low-frequency band in the antenna 10A may deteriorate, for example.
Then, the antenna device 1A according to the embodiment of the present disclosure includes the filter 40 as will be described later, to thereby improve the isolation between the antennas 10A and 20A.
The filter 40 is a circuit element to attenuate signals in a predetermined frequency band. In the embodiment of the present disclosure, the filter 40 attenuates signals in an unwanted frequency band in the frequency band of radio waves supported by the antenna 20A. In the embodiment of the present disclosure, the unwanted frequency band is the low-frequency band (699 to 960 MHz band), for example, in the frequency band of radio waves supported by the antenna 10A. The filter 40 does not have to attenuate signals throughout the low-frequency band, but may attenuate signals in a part of the low-frequency band.
In the antenna device 1A according to the embodiment of the present disclosure, as illustrated in
In the embodiment of the present disclosure, as illustrated in
In
The filter 40 may be a high-pass filter (HPF) 41 as illustrated in
The filter 40 may be a band pass filter (BPF) 42 as illustrated in
The filter 40 may be a band elimination filter (BEF) 43 as illustrated in
Each of the filters illustrated in
As described above, the antenna device 1A according to the embodiment of the present disclosure includes the filter 40, which is configured with the high-pass filter 41, the band pass filter 42, or the band elimination filter 43, to thereby improve isolation between the antennas 10A and 20A. Although the filter 40 according to the embodiment of the present disclosure is a circuit element that attenuates signals in a predetermined frequency band, the filter 40 may be a surface acoustic wave (SAW) filter. Furthermore, the antenna device 1A does not have to include the filter 40 when the issue of isolation can be tolerated, depending on the communication standards of the antennas 10A and 20A or the level of received signals thereof.
The antenna device 1A may include a holder (not-illustrated) supporting at least any one of the antenna 10A, the antenna 20A, or the base portion 30A. The holder is made of resin and is provided at the ground portion 3. However, the holder may be made of a material other than resin.
The antennas 10A and 20A may be fixed to the case 2 by screwing, welding, adhesion, snap fitting, or the like, instead of the aforementioned holder. This can improve the ease of assembly of the antenna device 1A. Furthermore, this can stabilize the distance between the end portions of the first element 11A and the second element 21A, which are positioned adjacent to each other, thereby being able to stabilize the capacitive coupling. The first element 11A of the antenna 10A and the second element 21A of the antenna 20A may have holes in order to be welded onto the case 2.
The antenna device 1A may include another antenna in addition to the antennas 10A and 20A. Such another antenna may be a planar antenna for Global Navigation Satellite Systems (GNSS), Satellite Digital Audio Radio Service (SDARS), or Electronic Toll Collection (ETC), for example.
The planar antenna for GNSS or SDARS may be a multilayer or multistage antenna, in the case where the size in the up-down direction in the antenna device 1A is not strictly limited or other cases. This enables the planar antenna to support radio waves in plural frequency bands. Furthermore, the planar antenna may support radio waves in plural frequency bands by including a radiation element with an opening, such as a slot.
Such another antenna provided in addition to the antennas 10A and 20A is not limited to aforementioned antennas, and may be an antenna supporting radio waves in a frequency band used in telematics, V2X, Wi-Fi, Bluetooth, or DAB.
As described above, the antenna device 1A according to the embodiment of the present disclosure includes the capacitive coupling portion 35, which is implemented by the end portions of the first element 11A and the second element 21A. This allows the low-frequency band supported by the first element 11A to have a bandwidth expanded toward the lower frequency side in the antenna device 1A according to the embodiment of the present disclosure. The following description verifies the characteristics of the antenna 10A of the antenna device 1A according to the embodiment of the present disclosure using a comparative example. First, an antenna device 1X of the comparative example illustrated in
In the antenna device 1X of the comparative example, a second element 21X of an antenna 20X does not include a configuration corresponding to the additional element portion 23 of the antenna device 1A according to the embodiment of the present disclosure, as illustrated in
The configuration of the antenna device 1X of the comparative example is the same as that of the antenna device 1A of the first embodiment except that the above-described additional element portion 23 and filter 40 are not included. Specifically, the antenna device 1X of the comparative example includes an antenna 10X, which is the same as the antenna 10A of the antenna device 1A according to the embodiment of the present disclosure, and a base portion 30X, which is the same as the base portion 30A of the antenna device 1A according to the embodiment of the present disclosure. The base portion 30X is coupled to a first element 11X of the antenna 10X and the second element 21X of the antenna 20X.
The configuration of the first element 11X of the antenna 10X of the comparative example is the same as that of the first element 11A of the antenna 10A according to the embodiment of the present disclosure. Specifically, the first element 11X includes: a standing portion 12X, which is the same as the standing portion 12A according to the embodiment of the present disclosure; an extending portion 13X, which is the same as the extending portion 13A according to the embodiment of the present disclosure; and a short-circuit portion 17X, which is the same as the short-circuit portion 17A according to the embodiment of the present disclosure. The first element 11X includes portions individually corresponding to the low-frequency, mid-frequency, and high-frequency bands similarly to the antenna device 1A embodiment (detailed illustration thereof is omitted).
Next, the antenna 10A according to the embodiment of the present disclosure and the antenna 10X of the comparative example are compared in frequency characteristics.
In
The frequency characteristics of the antenna 10A according to the embodiment of the present disclosure are compared between the case where the antenna 10A does not include the filter 40 (the antenna 10A without the filter 40) and the case where the antenna 10A includes the filter 40 (the antenna 10A with the filter 40). In each of the graphs, the result of the antenna 10A without the filter 40 is given by a solid line, and the result of the antenna 10A with the filter 40 is given by a dashed line.
As illustrated in
Next, as illustrated in
As illustrated in
Meanwhile, as illustrated in
From the aforementioned verification results, it is understood that the antenna device 1A according to the embodiment of the present disclosure is improved, in frequency characteristics in the low-frequency band, as compared with the antenna device 1X of the comparative example. As described above, in the antenna device 1A according to the embodiment of the present disclosure, the end portions of the first and second elements 11A and 21A are positioned adjacent to each other, to thereby be capacitively coupled. This implements the capacitive coupling portion 35, thereby being able to expand the band corresponding to the low-frequency band supported by the first element 11A toward the lower frequency side, in the antenna device 1A according to the embodiment of the present disclosure.
Furthermore, the antenna device 1A according to the embodiment of the present disclosure includes the filter 40, thereby being able to improve isolation.
Although the detailed description is omitted, the characteristics (VSWR and isolation) of the antenna 10A according to the embodiment of the present disclosure are good in the mid/high frequency band as well, with some exceptions, as illustrated in
In the antenna device 1A of the aforementioned first embodiment, the capacitive coupling portion 35 is implemented by the end portion of the first element 11A and a part (the end portion of the second element 21A) of the antenna 20A. However, the second element (second elements 21B to 21D) may be configured with a parasitic element as in antenna devices 1B and 1C according to the embodiment of the present disclosure which will be described later.
In the antenna device 1B of the first example of the embodiment of the present disclosure, a second element 21B to implement the capacitive coupling portion 35 is a parasitic element. The second element 21B is formed so as to stand from the ground portion 3 and be adjacent to a first additional portion 15B of a first element 11B of an antenna 10B.
This also makes it possible to generate two resonances in the low-frequency band, with the first element 11B of the antenna 10B and the second element 21B which is a parasitic element, in the antenna device 1B of the first example of the embodiment of the present disclosure, thereby being able to expand the band corresponding to the low-frequency band supported by the first element 11B further to the lower frequency side. Accordingly, the antenna 10B of the antenna device 1B according to the embodiment of the present disclosure can easily achieve a wider frequency band.
The configuration of the antenna device 1B of the first example of the embodiment of the present disclosure is similar, although including a slight difference in shape, to that of the previously described antenna device 1A except the configuration of the aforementioned second element 21B. Specifically, similarly to the antenna device 1A of the first embodiment, the first element 11B of the antenna 10B is coupled to the base portion 30B, and includes a standing portion 12B, an extending portion 13B, and a short-circuit portion not illustrated in
The antenna device 1B of the first example of the embodiment of the present disclosure mainly supports the low-frequency band with the standing portion 12B, main portion 14B, first additional portion 15B, and not-illustrated short-circuit portion. The antenna device 1B of the first example of the embodiment of the present disclosure mainly supports the mid-frequency band with the standing portion 12B, main portion 14B, second additional portion 16B, and a short-circuit portion (not-illustrated). The antenna device 1B of the first example of the embodiment of the present disclosure mainly supports the high-frequency band with the standing portion 12B.
In the antenna device 1B of the first example of the aforementioned second embodiment, the standing portion 12B of the first element 11B is formed so as to stand on the upper side of the base portion 30B. However, the configuration of the first element is not limited to this.
The antenna device 1C of the second example of the embodiment of the present disclosure includes an antenna 10C and a base portion 30C, similarly to the antenna device 1A of the first embodiment and the antenna device 1B of the first example of the embodiment of the present disclosure.
The antenna 10C of the second example of the embodiment of the present disclosure includes the first element 11C and the feed portion 18, similarly to the antenna 10A of the first embodiment and the antenna 10B of the first example of the embodiment of the present disclosure. The first element 11C of the second example of the embodiment of the present disclosure has the same configuration as that of the first element 11A of the first embodiment and the first element 11B of the first example of the embodiment of the present disclosure. Specifically, the first element 11C includes a standing portion 12C, an extending portion 13C, and a short-circuit portion 17C (illustrated in
The first element 11C of the second example of the embodiment of the present disclosure mainly supports the low-frequency band, with the standing portion 12C, main portion 14C, first additional portion 15C, and short-circuit portion 17C, similarly to the first element 11A of the first embodiment. The antenna device 1C of the second example of the embodiment of the present disclosure mainly supports the mid-frequency band, with the standing portion 12C, main portion 14C, second additional portion 16C, and short-circuit portion 17C. The antenna device 1C of the second example of the embodiment of the present disclosure mainly supports the high-frequency band with the standing portion 12C.
In the antenna 10C of the second example of the embodiment of the present disclosure, the standing portion 12C is spaced apart from the base portion 30C in the +X direction. In other words, the standing portion 12C is positioned (offset) at a predetermined distance in the +X direction from the base portion 30C. Similarly, the end portion of the first element 11C on the base portion 30C side (i.e., the end portion of the main portion 14C on the base portion 30C side) is positioned (offset) at a predetermined distance in the +X direction from the end portion of the base portion 30C on the first element 11C side, as illustrated in
In the antenna 10C of the second example of the embodiment of the present disclosure, the standing portion 12C is spaced apart from the base portion 30C, such that the standing portion 12C can be provided so as to extend to the ground portion 3 side relative to the base portion 30C. In the antenna device 1C of the second example of the second embodiment, the standing portion 12C and the ground portion 3 are not electrically connected, as illustrated in
Similarly to the base portion 30A of the first embodiment, the base portion 30C is positioned between the extending portion 13C and the ground portion 3 as illustrated in
When the size in the up-down direction in the antenna device 1C is strictly limited, for example, it may be difficult to secure the length of the standing portion 12C. Furthermore, when the base portion 30C is positioned above the ground portion 3, as in the antenna device 1C of the second example of the embodiment of the present disclosure, and the standing portion 12C is provided so as to stand from the base portion 30C, it is more difficult to secure the length of the standing portion 12C in the up-down direction.
Thus, the lower end portion of the standing portion 12C is provided so as to extend further to the ground portion 3 side, as in the antenna 10C of the second example of the embodiment of the present disclosure, thereby making it easier to secure the length of the standing portion 12C in the up-down direction. This makes it easier to form the standing portion 12C so as to have a length corresponding to a wavelength (e.g., the wavelength at 699 MHz) used in the low-frequency band.
In the antenna device 1C of the second example of the embodiment of the present disclosure, a first element coupling portion 19 is provided at the end portion in the down direction (in the −Z direction) of the standing portion 12C, as illustrated in
In the antenna device 1C of the second example of the embodiment of the present disclosure as well, a second element 21C, which implements the capacitive coupling portion 35, is a parasitic element, similarly to the first example. The second element 21C of the second example of the embodiment of the present disclosure includes a standing portion 28 and an extending portion 29.
The standing portion 28 is a portion formed in the second element 21C so as to stand against the base portion 30C. In the second example of the embodiment of the present disclosure, the standing portion 28 is formed so as to stand in the up direction against the base portion 30C. The direction in which the standing portion 28 stands against the base portion 30C is not limited to the up direction (the +Z direction), and may be a direction inclined at a predetermined angle relative to the base portion 30C.
In the antenna device 1C of the second example of the embodiment of the present disclosure, a second element coupling portion 26 is provided at the end portion in the down direction (in the −Z direction) of the standing portion 28, as illustrated in
The extending portion 29 is a portion formed so as to extend from the standing portion 28. Further, the extending portion 29 is a portion formed so as to face the ground portion 3. In the second example of the embodiment of the present disclosure, the extending portion 29 is formed so as to extend from the upper end portion of the standing portion 28, as illustrated in
In the antenna device 1C of the second example of the embodiment of the present disclosure, the end portion of the extending portion 29 is provided so as to be adjacent to the end portion of the first additional portion 15C in the extending portion 13C of the first element 11C. Accordingly, in the second example of the embodiment of the present disclosure, the extending portion 29 is provided so as to be capacitively coupled to the end portion of the first element 11C. This implements the capacitive coupling portion 35 at the end portion of the extending portion 29 in the second example of the embodiment of the present disclosure as well.
The antenna device 1C of the second example of the second embodiment includes a circuit element 50 at a coupling portion that couples the second element 21C and the base portion 30C, as illustrated in
As illustrated in
In the following, the antennas 10B and 10C of the embodiment of the present disclosure are compared in frequency characteristics.
In
As illustrated in
In other words, it is understood that, in the antenna 10C, as described above, the lower end portion of the standing portion 12C can be provided so as to extend further to the ground portion 3 side, thereby making it easy to secure the length of the standing portion 12C in the up-down direction, which makes it easy to form the standing portion 12C so as to have a length corresponding to a wavelength (e.g., the wavelength at 699 MHz) used in the low-frequency band.
Although the detailed description is omitted, the characteristics (VSWR and radiation efficiency) of the antennas 10B and 10C of the embodiment of the present disclosure are good in the mid/high frequency band as well, with some exceptions, as illustrated in
Note that, in the antenna device 1C of the second example of the embodiment of the present disclosure, the antenna 10C and base portion 30C are arranged in a housing space defined by the case 2 and the ground portion 3, as in the antenna device 1A of the first embodiment. However, a part of a first element 11D of an antenna 10D may be provided outside the housing space, as in an antenna device 1D of a third example of the embodiment of the present disclosure.
The antenna device 1D of the third example of the embodiment of the present disclosure has a configuration similar, although including a slight difference in shape, to the aforementioned antenna device 1D of the second example of the embodiment of the present disclosure, except the positions where the first and second elements 11D and 21D are arranged. The following mainly descries differences from the antenna device 1D of the second example of the embodiment of the present disclosure.
In the antenna device 1D of the third example of the second embodiment, a part of the first element 11D of the antenna 10D is arranged outside the case 2, as illustrated in
In the antenna device 1D of the third example of the embodiment of the present disclosure, the end portion of the extending portion 29 is provided so as to be adjacent to the end portion of the first additional portion 15D in the extending portion 13D of the first element 11D, similarly to the antenna 10C of the second example of the embodiment of the present disclosure. Accordingly, the extending portion 29 is provided so as to be capacitively coupled to the end portion of the first element 11D in the third example of the embodiment of the present disclosure. This also implements the capacitive coupling portion 35 at the end portion of the extending portion 29, as illustrated in
However, the positions where the first and second elements 11D and 21D are arranged are not limited to the positions illustrated in
In the following, the frequency characteristics of the antenna 10D according to the embodiment of the present disclosure are verified.
In
As illustrated in
Accordingly, from the aforementioned verification results, it is understood that, in the antenna device 1D according to the embodiment of the present disclosure as well, the frequency characteristics are improved in the low-frequency band. As described above, in the antenna device 1D of the embodiment of the present disclosure, the end portions of the first element 11D and second element 21D are positioned so as to be adjacent to each other, thereby being able to be capacitively coupled. This implements the capacitive coupling portion 35, thereby being able to further expand the band corresponding to the low-frequency band supported by the first element 11D toward the lower frequency side, in the antenna device 1D according to the embodiment of the present disclosure.
Although the detailed description is omitted, the characteristics (VSWR and radiation efficiency) of the antenna 10D of the third example of the embodiment of the present disclosure are good in the mid/high frequency band as well, with some exceptions, as illustrated in
Hereinabove, the antenna devices 1A to 1D which are embodiments of the present disclosure are described.
The antenna device 1A of the first embodiment includes: the first element 11A; the second element 21A capacitively coupled to the first element 11A; and the base portion 30A coupled to the first and second elements 11A and 21A, as illustrated in
The antenna device 1B of the first example of the second embodiment includes: the first element 11B; the second element 21B, which is capacitively coupled to the first element 11B; and the base portion 30B coupled to the first and second elements 11B and 21B, as illustrated in
The antenna device 1C of the second example of the second embodiment includes: the first element 11C; the second element 21C capacitively coupled to the first element 11C; and the base portion 30C coupled to the first and second elements 11C and 21C, as illustrated in
The antenna device 1C of the third example of the second embodiment includes: the first element 11D; the second element 21D capacitively coupled to the first element 11D; and the base portion 30D coupled to the first and second elements 11D and 21D, as illustrated in
Herein, the low-frequency band (699 to 960 MHz) corresponds to a “first frequency band”.
In the antenna device 1A of the first embodiment, the second element 21A supports radio waves in a frequency band (e.g., the frequency band of 1710 to 5000 MHz for Sub-6 GHz) different from the low-frequency band (e.g., 699 to 960 MHz) as illustrated in
In the antenna device 1A of the first embodiment, the base portion 30A includes the first region 31 coupled to a feed line, and the second region 32 coupled to the second element 21A, and the antenna device 1A includes the filter 40 configured to attenuate signals in the low-frequency band (699 to 960 MHz) provided between the first and second regions 31 and 32, as illustrated in
In the antenna device 1B of the first example of the second embodiment, the second element 21B is a parasitic element, as illustrated in
In the antenna device 1C of the second example of the second embodiment, the second element 21C is a parasitic element as illustrated in
In the antenna device 1D of the third example of the second embodiment, the second element 21D is a parasitic element, as illustrated in
In the antenna device 1C of the second example of the second embodiment, as illustrated in
The antenna device 1B of the first example of the second embodiment may similarly include the circuit element 50 although not illustrated. This makes it possible to improve the characteristics of the antenna (the antenna 10B herein) included in the antenna device 1B, in the low-frequency band (699 to 960 MHz).
The antenna device 1D of the third example of the second embodiment may similarly include the circuit element 50 although not illustrated. This makes it possible to improve the characteristics of the antenna (the antenna 10D herein) included in the antenna device 1D, in the low-frequency band (699 to 960 MHz).
In the antenna device 1C of the second example of the second embodiment, the circuit element 50 is a resistor to terminate signals in the first frequency band, as illustrated in
In the antenna device 1B of the first example of the second embodiment as well, the circuit element 50 may similarly be a resistor although not illustrated. This makes it possible to improve the characteristics of the antenna (the antenna 10B herein) included in the antenna device 1B, in the low-frequency band (699 to 960 MHz).
In the antenna device 1D of the third example of the second embodiment as well, the circuit element 50 may similarly be a resistor although not illustrated. This makes it possible to improve the characteristics of the antenna (the antenna 10D herein) included in the antenna device 1D, in the low-frequency band (699 to 960 MHz).
As illustrated in
As illustrated in
In the antenna device 1C of the second example of the second embodiment, the standing portion 12C and the ground portion 3 are not electrically connected, as illustrated in
In the antenna device 1D of the third example of the second embodiment, the standing portion 12D and the ground portion 3 are not electrically connected, as illustrated in
In the antenna device 1C of the second example of the second embodiment, as illustrated in
In the antenna device 1D of the third example of the second embodiment, as illustrated in
In the antenna device 1C of the second example of the second embodiment, as illustrated in
In the antenna device 1D of the third example of the second embodiment as well, the first element 11D may similarly include a short-circuit portion coupled to the ground portion 3, although not illustrated. The second element 21D, the standing portion 12D, the main portion 14D, the first additional portion 15D, and the short-circuit portion may mainly support the low-frequency band (699 to 960 MHz). The standing portion 12D, the main portion 14D, the second additional portion 16D, and the short-circuit portion may mainly support the mid-frequency band (1710 to 2690 MHz) whose frequencies are higher than the low-frequency band. The standing portion 12D may mainly support a frequency band (e.g., the high-frequency band, 3300 to 5000 MHz) whose frequencies are higher than the mid-frequency band. This enables the antenna (the antenna 10D herein) included in the antenna device 1D to support radio waves in a frequency band other than the low-frequency band (699 to 960 MHz).
Herein, the mid-frequency band (1710 to 2690 MHz) corresponds to a “second frequency band”.
In the antenna device 1A of the first embodiment, as illustrated in
In the antenna device 1B of the first example of the second embodiment as well, the first element 11B may similarly include a short-circuit portion coupled to the ground portion 3, although not illustrated, for example. This makes it possible to facilitate impedance matching of an antenna (the antenna 10B herein) included in the antenna device 1B.
In the antenna device 1C of the second example of the second embodiment as well, the first element 11C may similarly include the short-circuit portion 17C coupled to the ground portion 3, as illustrated in
In the antenna device 1D of the third example of the second embodiment as well, the first element 11D may similarly include a short-circuit portion coupled to the ground portion 3, although not illustrated. This makes it possible to facilitate impedance matching of an antenna (the antenna 10D herein) included in the antenna device 1D.
Embodiments of the present disclosure described above are simply to facilitate understanding of the present disclosure and are not in any way to be construed as limiting the present disclosure. The present disclosure may variously be changed or altered without departing from its essential features and encompass equivalents thereof.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2021/045671 | 12/10/2021 | WO |
Number | Date | Country | |
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63124327 | Dec 2020 | US |