The present invention relates to a line conversion structure in which a high-frequency transmission line formed in a dielectric layer is converted into a slot line, and in particular to a line conversion structure suitable for interlayer connection in a transmission line, connection to an antenna, connection to a waveguide, or the like in a semiconductor element storage package or a wiring board that is preferable for housing or mounting semiconductor elements intended for high frequencies ranging from microwave to millimeter-wave frequency bands, and to an antenna using such a line conversion structure.
With the arrival of the advanced information age in recent years, utilization of radio waves ranging from the microwave frequency band of 1 to 30 GHz to even the millimeter-wave frequency band of 30 to 300 GHz for information transmission is being considered. For example, an applied system such as a domestic high-speed wireless transmission system (wireless personal area network (PAN)) using 60 GHz has now been proposed.
Conventionally, with a wiring board in/on which semiconductor elements for high frequencies (hereinafter simply referred to as “high-frequency elements”) used in such an applied system or the like are housed/mounted, interlayer connection in a transmission line or connection to an antenna, for example, is in many cases established via a slot line.
A wiring board disclosed in Patent Literature 1 is known as an example of a wiring board using such transmission line connection via a slot line. In this wiring board, a microstrip line configured in an upper dielectric layer and an output microstrip line configured in a lower dielectric layer are connected at high frequencies with electromagnetic coupling via a slot provided between the dielectric layers.
The characteristic of the electromagnetic coupling between the microstrip lines and the slot in such a wiring board varies depending on a stub length and a slot length, the stub length being a length from an open end of each microstrip line to the center of the slot. In the case where such a wiring board is manufactured using a printing or lamination technique, the variation in the slot length is determined by only the variation in print dimensions and is thus relatively small. On the other hand, the variation in the stub length readily increases due to the variation in print position in forming the microstrip lines, the variation in print position in forming the slot, and layer-to-layer misalignment in laminating the upper and lower dielectric layers, which results in the problem that there is variation in the characteristic of the electromagnetic coupling between the microstrip lines and the slot.
A wiring board disclosed in Patent Literature 2 is also known as an example of a line conversion structure in which a line for transmitting high frequencies is converted into a slot line. This example gives a wiring board for connecting a coplanar line to a dielectric waveguide via a slot formed in the same plane as the coplanar line. In this case, since the coplanar line and the slot are formed in the same plane, the variation in the stub length is relatively small because it depends only on the variation in print dimensions without experiencing the influence of the variation in print position and the layer-to-layer misalignment as described in the above case. Accordingly, the variation in the characteristic of the conversion from the coplanar line to the slot is reduced.
Furthermore, a wiring board disclosed in Patent Literature 3 is known as an example of a line conversion structure in which a microstrip line is converted into a coplanar line. This example gives a wiring board in which the conversion into a coplanar line is achieved by, while reducing the width of a signal conductor of the microstrip line, forming a ground conductor on both sides of the signal conductor with a gap provided between the ground conductors and the signal conductor, and reducing these gaps so as to make the impedance constant. With such a wiring board, it is not easy to prepare such a design for reducing the gaps between the signal conductor and the ground conductors formed on both sides of the signal conductor in order to make the impedance constant.
It is an object of the invention to provide a line conversion structure that converts a high-frequency transmission line into a slot line with a small variation in conversion characteristics and a small loss in conversion.
A line conversion structure according to an embodiment of the invention is a line conversion structure for converting a high-frequency transmission line into a slot line. The high-frequency transmission line includes a dielectric layer, a signal conductor disposed on an upper surface of the dielectric layer, and a ground layer disposed on a lower surface of the dielectric layer. The slot line includes a slot ground conductor, a slot signal conductor, and a slot. The slot ground conductor is disposed on the upper surface of the dielectric layer and connected to the ground layer with a through conductor that passes through the dielectric layer. The slot signal conductor is disposed on the upper surface of the dielectric layer. The slot is disposed between the slot ground conductor and the slot signal conductor. The signal conductor of the high-frequency transmission line is orthogonal to the slot ground conductor and the slot, with a gap between the signal conductor and the slot ground conductor, and an end of the signal conductor is connected to the slot signal conductor. A length of a portion of the slot ground conductor, the portion being parallel to the signal conductor with the gap, is less than or equal to 0.25 time a wavelength of a signal transmitted through the high-frequency transmission line.
An antenna according to an embodiment of the invention includes the above-described line conversion structure in which both end portions of the slot are closed, a lower dielectric layer, a lower ground layer, a first opening, a second opening, and a plurality of shield conductors. The lower dielectric layer is formed on the lower surface of the dielectric layer. The lower ground layer is formed on a lower surface of the lower dielectric layer. The first opening is formed in a portion of the ground layer that faces the slot. The second opening is formed in a portion of the lower ground layer that faces the slot. The plurality of shield conductors are configured to surround the first opening and the second opening in a plan view, and to connect the ground layer and the lower ground layer.
In the line conversion structure according to the embodiment of the invention, the signal conductor of the high-frequency transmission line is orthogonal to the slot ground conductor and the slot, with a gap between the signal conductor and the slot ground conductor, an end of the signal conductor is connected to the slot signal conductor, and the length of the portion of the slot ground conductor, the portion being parallel to the signal conductor with the gap, is less than or equal to 0.25 times the wavelength of the signal transmitted through the high-frequency transmission line. Accordingly, in the portion where the signal conductor is orthogonal to the slot ground conductor with a gap between the signal conductor and the slot ground conductor, no transition to a coplanar line transmission mode occurs, and the high-frequency transmission line can be converted directly into the slot line. This also produces no resonance, thus achieving a line conversion structure with a small loss in conversion.
As described above, the antenna according to the embodiment of the invention includes the line conversion structure of the above embodiment of the invention, in which both end portions of the slot are closed, the lower dielectric layer, the lower ground layer, the first opening, the second opening, and the plurality of shield conductors. Thus, with such an antenna, signals that have been transmitted through the high-frequency transmission line are stored efficiently in the slot line as signal energy, and of the lower dielectric layer disposed on the underside of the slot, a portion that is surrounded by the shield conductors functions as a dielectric matching unit that achieves high-frequency matching between the slot and a space located on the underside of the lower dielectric layer. Accordingly, it is possible to emit signals through the first opening and the second opening to the space with a small loss (high efficiency).
Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein:
Hereinafter, an embodiment of a line conversion structure according to the invention will be described in detail with reference to the attached drawings. A microstrip line 1 serving as a high-frequency transmission line, a dielectric layer 2, a lower dielectric layer 2a, a signal conductor 3, a ground layer 4, a first opening 4a, a slot line 5, through conductors 6, ground-reinforcing conductors 6a, upper ground-reinforcing conductors 6b, a slot ground conductor 7, a slot signal conductor 8, a slot 9, a slot pattern conductor 9a, an upper dielectric layer 10 or 16, an upper ground layer 11 or 17, an output signal conductor 12, an output microstrip line 13, and a strip line 18 serving as a high-frequency transmission line are shown in
Furthermore, with the configuration described above, if a distance (indicated by D in
Although the upper ground layer 11 is formed only over the line conversion unit in the example shown in
Furthermore, as in the example shown in
If a slot pattern conductor 9a is disposed on the upper surface of the dielectric layer 2 so as to close at least one end portion of the slot 9, it is possible to change the direction of signal transmission to the desired direction. For example, if the slot pattern conductor 9a is disposed so as to close only one end portion of the slot 9 as in the example shown in
In the line conversion structure in the example shown in
Furthermore, in the line conversion structure in the example shown in
Furthermore, in the above-described configuration, it is preferable that there is provided upper ground-reinforcing conductors 6b that pass through the upper dielectric layer 16 and connect the slot ground conductor 7 and the upper ground layer 17. The provision of the upper ground-reinforcing conductors 6b in this way enables the potential at the end portions of the slot 9 on the slot ground conductor 7 side to be closer to the ground potential, thus further suppressing a reduction in gain.
Furthermore, if the two slot pattern conductors 9a are disposed so as to close both end portions of the slot 9 as in the example shown in
By using the line conversion structure of the embodiment with such a configuration, a low-loss antenna can be configured.
The antenna in the example shown in
If the line conversion structure provided in the antenna has a lower-loss structure as described above, the antenna will also achieve a smaller loss (higher efficiency). In the line conversion structure, a loss in conversion from the microstrip line 1 to the slot line 5 is further reduced if the length (indicated by in
Furthermore, in the above-described configuration of the antenna of the embodiment, if the first opening 4a has a shorter length than the second opening 14a in the direction parallel to the signal conductor 3 as in the example shown in
The thickness of the lower dielectric layer 2a is set to one fourth the wavelength of signals in the lower dielectric layer 2a, so that the portion of the lower dielectric layer 2a that is surrounded by the shield conductors 15 functions as a dielectric matching unit that achieves impedance matching between the slot 9 and a space below the lower dielectric layer 2a into which signals are to be emitted. Since the wavelength of signals in the lower dielectric layer 2a varies depending on the frequency of signals transmitted through the microstrip line 1 and the effective dielectric constant of the lower dielectric layer 2a, the thickness of the lower dielectric layer 2a is set in accordance therewith.
The plurality of shield conductors 15 are formed in the lower dielectric layer 2a and arranged so as to surround the first opening 4a and the second opening 14a in a plan view. Each of the shield conductors 15 connects the ground layer 4 and the lower ground layer 14. The shield conductors 15 are preferably arranged in close proximity outside the second opening. Since signals that have passed through the first opening 4a pass through the portion surrounded by the shield conductors 15, if a portion of the lower ground layer 14 that is located inside the shield conductors 15 is made smaller, it is possible to suppress interference with signal emissions in that portion. More preferably, the shield conductors 15 may be arranged adjacently outside the second opening 14a. In this case, the lower ground layer 14 will not interfere with signal emissions because there is almost no lower ground layer 14 inside the shield conductors 15.
The distances between the plurality of shield conductors 15 are preferably less than or equal to one fourth the wavelength of signals transmitted through the dielectric matching unit, so as to avoid leakage of high-frequency signals from the gaps between the adjacent shield conductors 15.
The slot 9, the first opening 4a, and the second opening 14a are disposed so as to face one another, i.e., to overlap one another in a plan view. In order to prevent the ground layer 4 from interfering with signal emissions from the slot 9 to the lower dielectric layer 2a, the first opening 4a is larger than the slot 9, and the first opening 4a and the slot 9 are disposed so as to make their centers coincide. Also, in order to prevent the lower ground layer 14 from interfering with emissions of signals, which have passed through the first opening 4a, into the space below the lower dielectric layer 2a, the second opening 14a is larger than the first opening 4a, and the first opening 4a and the second opening 14a are disposed so as to make their centers coincide. Such dimensions and disposition of the slot 9, the first opening 4a, and the second opening 14a enable signals to be favorably emitted from the slot 9 through the first opening 4a and the second opening 14a into the space thereunder.
In terms of the size relationship between the first opening 4a and the second opening 14a, it is in particular preferable, as mentioned above, that the first opening 4a has a shorter length than the second opening 14a in the direction parallel to the signal conductor 3. By doing so, it is possible to suppress the occurrence of a magnetic field of unnecessary resonance in the dielectric matching unit as a result of excitation caused by a magnetic field occurring around the signal conductor 3, in particular, a disturbed magnetic field occurring in a portion of the signal conductor 3 that is sandwiched by the slot ground conductor 7 and in which signals are to be converted. A magnetic field of unnecessary resonance in the dielectric matching unit is likely to occur along the outer periphery of the dielectric matching unit (a region close to the shield conductors 15), and a magnetic field of unnecessary resonance occurs as a result of excitation caused by a magnetic field occurring around the signal conductor 3, that is, a magnetic field occurring in a direction perpendicular to the signal conductor 3 in a plan view. For this reason, a magnetic field of unnecessary resonance is likely to occur in a portion on the outer periphery of the dielectric matching unit that extends in the direction perpendicular to the signal conductor 3. If the first opening 4a has a shorter length than the second opening 14a in the direction parallel to the signal conductor 3, the ground layer 4 is between the portion where a magnetic field of unnecessary resonance is likely to occur and the signal conductor 3, and the ground layer 4 can serve as a shield against a magnetic field occurring around the signal conductor 3. It is thus possible to suppress the occurrence of a magnetic field of unnecessary resonance. Since a magnetic field of unnecessary resonance is likely to concentrate in a region that ranges within one fourth the distance between the shield conductors 15 and the center of the dielectric matching unit from the shield conductors 15, it is preferable that the length of the first opening 4a in the direction parallel to the signal conductor 3 (indicated by OL1 in
The dielectric layer 2, the upper dielectric layer 10 or 16, and the lower dielectric layer 2a are made of ceramics, an organic resin, or a composite of these two. Examples of the ceramics include ceramic materials such as an alumina (Al2O3) sintered compact, an aluminum nitride (AlN) sintered compact, and a silicon nitride (Si3N4) sintered compact, glass materials, and glass ceramic materials made of a complex of glass and an inorganic filler such as Al2O3, SiO2, or MgO. Examples of the organic resins include fluorocarbon resins such as tetrafluoroethylene resins (polytetrafluoroethylene (PTFE)), ethylene-tetrafluoroethylene copolymer resins (ethylene-tetrafluoroethylene copolymer resin (ETFE)), and tetrafluoroethylene-perfluoroalkoxy ethylene copolymer resins (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resins (PFA)), epoxy resins, glass-epoxy resins, and polyimide. In the case of using a ceramic material, it is preferable to use a glass ceramic material that is capable of being co-fired with a conductor material made of a low-resistance metal such as Au, Ag, or Cu that is capable of transmitting high-frequency signals. The thickness of the dielectric layer 2 made of these materials is set according to the frequency to be used or the application, for example.
If the dielectric layer 2 is made of a ceramic material, the signal conductor 3, the ground layer 4, the slot ground conductor 7, the slot signal conductor 8, the slot pattern conductor(s) 9a, the upper ground layer 11 or 17, and the lower ground layer 14 are formed of a metalized layer that is made primarily of a metal such as W, Mo, Mo—Mn, Au, Ag, or Cu. If the dielectric layer 2 is made of an organic resin, these conductors and layers are formed of a metal layer formed by a thick-film printing method, various types of thin-film forming methods, a plating method, a foil transfer method, or the like, or formed of a layer configured by forming a plating layer on such a metal layer, examples of which include a Cu layer, a Cr—Cu alloy layer, a layer configured by depositing a Ni plating layer and a Au plating layer on a Cr—Cu alloy layer, a layer configured by depositing a Ni—Cr alloy layer and a Au plating layer on a TaN layer, a layer configured by depositing a Pt layer and a Au plating layer on a Ti layer, and a layer configured by depositing a Pt layer and a Au plating layer on a Ni—Cr alloy layer. The thicknesses and widths thereof are set according to the frequency of high-frequency signals to be transmitted or the application, for example.
A known method may be used to form the signal conductor 3, the ground layer 4, the slot ground conductor 7, the slot signal conductor 8, the slot pattern conductor(s) 9a, the upper ground layer 11 or 17, and the lower ground layer 14. For example, if the dielectric layer 2 is made of glass ceramics, green sheets of glass ceramics to be formed into the dielectric layer 2 are prepared first and then conductor patterns for the signal conductor 3, the ground layer 4, the slot ground conductor 7, the slot signal conductor 8, the slot pattern conductor(s) 9a, the upper ground layer 11 or 17, and the lower ground layer 14 are formed by applying conductor pastes such as Ag in a predetermined shape on the green sheets by printing using a screen printing technique. In this case, the signal conductor 3, the slot ground conductor 7, the slot signal conductor 8, and the slot pattern conductor(s) 9a are formed on the same green sheet at the same time. Then, the green sheets with the conductor patterns having formed thereon are, for example, overlaid and bonded to one another by pressing so as to create a laminated body, which is then shaped by undergoing firing at 850 to 1000° C. Thereafter, films of plating such as Ni plating and Au plating are formed over the conductors exposed to the outer surface. If the dielectric layer 2 is made of an organic resin material, for example, the signal conductor 3, the ground layer 4, the slot ground conductor 7, the slot signal conductor 8, the slot pattern conductor(s) 9a, the upper ground layer 11 or 17, and the lower ground layer 14 are formed by transferring, to organic resin sheets, Cu foils that have been processed into the shapes of the conductor patterns for these conductors and layers, and laminating and bonding the organic resin sheets, on which the Cu foils have been transferred, with an adhesive.
If the dielectric layer 2 is made of ceramics such as glass ceramics, the through conductors 6, the ground-reinforcing conductors 6a, and the upper ground-reinforcing conductors 6b can be formed by, for example prior to the formation of the conductor patterns for the signal conductor 3, the ground layer 4, the slot ground conductor 7, the slot signal conductor 8, the slot pattern conductor(s) 9a, the upper ground layer 11 or 17, and the lower ground layer 14 in the aforementioned manufacturing method, forming through holes in green sheets in advance by metal molding or laser machining and filling the through holes with a similar conductor paste using a print process or the like. Similarly, if the dielectric layer 2 is made of an organic resin, organic resin sheets are used instead of green sheets, and through conductors may be formed in through holes by printing or plating of a conductor paste. The shield conductors 15 may also be formed in the same manner as the through conductors 6, the ground-reinforcing conductors 6a, and the upper ground-reinforcing conductors 6b.
Simulations for verifying the effect of the line conversion structure of the invention were conducted using the example shown in
The length L of the portion of the slot ground conductor 7 that was parallel to the signal conductor 3 with a gap in between (hereinafter referred to as a “parallel length L”) was set to 0.25 times (0.5 mm) the wavelength of signals transmitted through the microstrip line 1, and the distance D between the signal conductor 3 and the through conductor 6 was set to 0.13 times (0.26 mm) the signal wavelength.
The results of the simulations of the loss performed using the above-described simulation model were shown in
Simulations were conducted using different parallel lengths L in the above simulation model, namely, 0.125 times (0.25 mm) the signal wavelength, 0.188 times (0.375 mm), 0.375 times (0.75 mm), 0.5 times (1.0 mm), 0.75 times (1.5 mm), and 1.0 times (2.0 mm). The results were collectively shown in
Simulations were conducted using different distances D between the signal conductor 3 and the through conductor 6 that was located closest to the portion parallel to the signal conductor 3 of the above simulation model (hereinafter simply referred to as the “distance D”), namely, 0.075 times (0.15 mm) the signal wavelength, 0.1 times (0.2 mm), 0.188 times (0.375 mm), 0.25 times (0.5 mm), and 0.375 times (0.75 mm). The results were collectively shown in
Simulations for verifying the effect of the antenna of the invention were conducted using the example shown in
The results of the simulations of the reflection performed using the above simulation model were shown in
[Test for Verifying Effect of Suppressing Reduction in Gain of Antenna]
Simulations for verifying the effect of suppressing a reduction in the gain of the antenna were conducted using the example shown in
<Relationship between Gain of Antenna and Slot Pattern Width>
(Test Case 1)
The first opening 4a for coupling the slot line 5 and the dielectric matching unit was provided in the ground layer 4 on the lower surface of the dielectric layer 2. Assuming that the upper dielectric layer 16, the dielectric layer 2, and the lower dielectric layer 2a were made of alumina, the relative dielectric constant was set to 9.2, the conductivity of the conductors assumed to be metalized with tungsten was set to 6.6×106 (S/m), and the signal frequency was set to 60 GHz. The thicknesses of the upper dielectric layer 16 and the dielectric layer 2 were set to 0.125 mm, the thickness of the lower dielectric layer 2a was set to 0.4 mm, and the width of the signal conductor 3 of the strip line 18 was set to 0.1 mm. The gap between the slot ground conductor 7 and the signal conductor 3 was set to 0.1 mm. The diameters of the through conductors 6 and the shield conductors 15 were set to 0.1 mm, and the distance D between the through conductor 6 and the signal conductor 3 was set to 0.23 mm. The width of the slot 9 (the distance between the slot ground conductor 7 and the slot signal conductor 8) was set to 0.1 mm, and the length SL was set to 0.8 mm. The width of the slot signal conductor 8 was set to 0.205 mm. Then, the two slot pattern conductors 9a were configured on the upper surface of the dielectric layer 2 so as to close both end portions of the slot 9, and the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.35 times (0.577 mm) the wavelength of signals transmitted through the strip line 18. Note that, in Test Case 1, the simulations were conducted on the assumption that neither ground-reinforcing conductors 6a nor the upper ground-reinforcing conductors 6b were formed.
(Test Case 2)
In Test Case 2, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.3 times (0.495 mm) the wavelength of signals transmitted through the strip line 18.
(Test Case 3)
In Test Case 3, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.25 times (0.412 mm) the wavelength of signals transmitted through the strip line 18.
(Test Case 4)
In Test Case 4, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.2 times (0.33 mm) the wavelength of signals transmitted through the strip line 18.
(Test Case 5)
In Test Case 5, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.15 times (0.247 mm) the wavelength of signals transmitted through the strip line 18.
The results of the simulations of the gain performed using the simulation model in Test Cases 1 to 5 described above were shown in Table 1 and
As can be seen from Table 1 and
<Relationship between Gain of Antenna and Clearance between Ground-Reinforcing Conductors and End Portions of Slot>
(Test Case 6)
In Test Case 6, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.25 times (0.412 mm) the wavelength of signals transmitted through the strip line 18, and the ground-reinforcing conductors 6a were disposed corresponding to the respective end portions of the slot 9 at positions that were spaced 0.25 times the wavelength of signals transmitted through the strip line 18 from the respective end portions of the slot 9 in directions away from the signal conductor 3 (that is, the clearance between the conductors and the end portions of the slot 9 was 0.25 times the wavelength). Note that in Test Case 6, the simulations were conducted on the assumption that no upper ground-reinforcing conductors 6b were formed.
(Test Case 7)
In Test Case 7, simulations were conducted in the same manner as in Test Case 6, with the exception that the clearance between the ground-reinforcing conductors 6a and the end portions of the slot 9 was set to 0.125 times the wavelength.
(Test Case 8)
In Test Case 8, simulations were conducted in the same manner as in Test Case 6, with the exception that the clearance between the ground-reinforcing conductors 6a and the end portions of the slot 9 was set to 0 times the wavelength, that is, the center positions of the ground-reinforcing conductors 6a were made coincide with the positions of the end portions of the slot 9.
(Test Case 9)
In Test Case 9, simulations were conducted in the same manner as in Test Case 6, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.15 times (0.247 mm) the wavelength of signals transmitted through the strip line 18, and the clearance between the ground-reinforcing conductors 6a and the end portions of the slot 9 was set to 0.15 times the wavelength.
(Test Case 10)
In Test Case 10, simulations were conducted in the same manner as in Test Case 6, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.15 times (0.247 mm) the wavelength of signals transmitted through the strip line 18, and the clearance between the ground-reinforcing conductors 6a and the end portions of the slot 9 was set to 0 times the wavelength, that is, the center positions of the ground-reinforcing conductors 6a were made coincide with the positions of the end portions of the slot 9.
The results of the simulations of the gain performed using the simulation model in Test Cases 6 to 10 described above were shown in Table 2 and
As can be seen from Table 2 and
<Position where Ground-Reinforcing Conductor is Disposed>
(Test Case 11)
In Test Case 11, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.25 times (0.412 mm) the wavelength of signals transmitted through the strip line 18, and the ground-reinforcing conductors 6a were provided on the extension of the signal conductor 3 so that the ground-reinforcing conductors 6a connected the slot signal conductor 8 and the ground layer 4.
The results of the simulations of the gain performed using the simulation model in Test Case 11 described above were shown in
<Number of Ground-Reinforcing Conductors Disposed>
(Test Case 12)
In Test Case 12, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.15 times (0.247 mm) the wavelength of signals transmitted through the strip line 18, and a ground-reinforcing conductor 6a was disposed corresponding to only one end portion of the slot 9 at a position that was spaced 0.15 times the wavelength of signals transmitted through the strip line 18 from the one end portion of the slot 9 in a direction away from the signal conductor 3 (that is, the clearance between the conductor and the one end of the slot 9 was 0.15 times the wavelength).
The results of the simulations of the gain performed using the simulation model in Test Case 12 described above were shown in Table 3.
As can be seen from Table 3, even if the ground-reinforcing conductor 6a was disposed corresponding to only one end portion of the slot 9, a reduction in gain was suppressed better than in Test Case 5 in which no ground-reinforcing conductors 6a were formed.
<Symmetry of Positions where Two Ground-Reinforcing Conductors are Disposed>
(Test Case 13)
In Test Case 13, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.15 times (0.247 mm) the wavelength of signals transmitted through the strip line 18, and the two ground-reinforcing conductors 6a were disposed at positions, specifically, at the position spaced 0.15 times the signal wavelength from one end portion of the slot 9 (i.e., the clearance between the conductor and the end of the slot 9 was 0.15 times the wavelength) and at the position spaced 0 times the signal wavelength from the other end portion of the slot 9 (i.e., the center position of the ground-reinforcing conductor 6a was made coincide with the position of the end portion of the slot 9). In other words, in Test Case 13, the positions where the two ground-reinforcing conductors 6a were disposed were asymmetrical with respect to the signal conductor 3.
The results of the simulation of the gain performed using the simulation model in Test Case 13 described above were shown in Table 4.
As can be seen from Table 4, if the two ground-reinforcing conductors 6a were disposed asymmetrically, although the effect of suppressing a reduction in gain was lower than in Test Case 9 in which they are disposed symmetrically, a reduction in gain was suppressed better than in Test Case 5 in which no ground-reinforcing conductors 6a were formed.
<Effect of Upper Ground-Reinforcing Conductor to Suppress Reduction in Gain>
(Test Case 14)
In Test Case 14, simulations were conducted in the same manner as in Test Case 1, with the exception that the length of the portions of the slot pattern conductors 9a that were perpendicular to the signal conductor 3 (slot pattern width SW) was set to 0.15 times (0.247 mm) the wavelength of signals transmitted through the strip line 18, the ground-reinforcing conductors 6a were disposed corresponding to the respective end portions of the slot 9 at positions spaced 0.15 times the signal wavelength from the end portions of the slot 9 in directions away from the signal conductor 3 (i.e., the clearance between the conductors and the end portions of the slot 9 was 0.15 times the wavelength), and the upper ground-reinforcing conductors 6b were disposed corresponding to the respective end portions of the slot 9 at positions spaced 0.15 times the signal wavelength from the end portions of the slot 9 in directions away from the signal conductor 3 (i.e., the clearance between the conductors and the end portions of the slot 9 was 0.15 times the wavelength).
(Test Case 15)
In Test Case 15, simulations were conducted in the same manner as in Test Case 14, with the exception that the upper ground-reinforcing conductors 6b were disposed corresponding to the respective end portions of the slot 9 at positions spaced 0 times the signal wavelength from the end portions of the slot 9 in directions away from the signal conductor 3 (i.e., the center positions of the upper ground-reinforcing conductors 6b were made coincide with the positions of the ends of the slot 9). In other words, in Test Case 15, the upper ground-reinforcing conductors 6b were disposed at positions that were shifted from the ground-reinforcing conductors 6a.
The results of the simulation of the gain performed using the simulation model in Test Cases 14 and 15 described above were shown in Table 5.
As can be seen from Table 6, the provision of the upper ground-reinforcing conductors 6b further suppressed a reduction in gain as compared with Test Case 9 in which no upper ground-reinforcing conductors 6b were provided. Also, a comparison between Test Case 14 and Test Case 15 showed that a reduction in gain was further suppressed by not disposing the upper ground-reinforcing conductors 6b at positions shifted from the ground-reinforcing conductors 6a.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.
Number | Date | Country | Kind |
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2009-289990 | Dec 2009 | JP | national |
2010-013207 | Jan 2010 | JP | national |
2010-148374 | Jun 2010 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2010/072720 | 12/16/2010 | WO | 00 | 11/30/2011 |