Hybrid circuit and butler matrix equipped with the same

Abstract

To provide a hybrid circuit using a printed circuit board, which is highly mass-producible and has low insertion loss, and a butler matrix equipped with the same.SOLUTION: A butler matrix includes a dielectric substrate 10, a first ground conductor portion 11 provided above the dielectric substrate 10, a second ground conductor portion 12 provided below the dielectric substrate 10, a first strip conductor 13 formed on the surface of the dielectric substrate 10, and a second strip conductor 14 formed on the back surface of the dielectric substrate 10, and a first air layer 15 is provided between the dielectric substrate 10 and the first ground conductor portion 11, and a second air layer 16 is provided between the dielectric substrate 10 and the second ground conductor portion 12.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a hybrid circuit and a Butler matrix including the same, and more particularly to a hybrid circuit for a frequency band of a 5G wireless communication system and a Butler matrix including the same. [Background technology]

[0002] The wireless communication terminal (User Equipment: UE) used in 5G wireless communication systems is equipped with multiple antennas and uses a communication technology called MIMO (Multiple Input Multiple Output), which uses these multiple antennas simultaneously. Furthermore, the UE also uses a technology that increases maximum transmission capacity by simultaneously transmitting and receiving signals at multiple frequencies. When testing such UE, it is necessary to input arbitrary signals from the measurement system to the multiple antennas, which requires reconnecting the connection cables to each antenna every time a test is performed. To simplify testing by eliminating this connection work, a method using a distribution circuit with a Butler matrix is ​​known.

[0003] There are several ways to realize a Butler matrix. In the structure disclosed in Patent Document 1, the input section, 3 dB coupler, phase shifter, and output section are connected by waveguides, but it is also possible to configure a Butler matrix using coaxial lines instead of waveguides. However, considering mass productivity, it is desirable to fabricate a Butler matrix using a printed circuit board in which conductors are printed on a dielectric substrate.

[0004] As a 3 dB coupler fabricated using a printed circuit board, there is one that uses a strip line, as shown in Non-Patent Document 1. The 3 dB coupler disclosed in Non-Patent Document 1 is a 3 dB quadrature hybrid coupler (hereinafter also referred to as a "hybrid circuit") that splits one input signal into two output signals that have a phase difference of 90 degrees from each other. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 137469 [Non-patent literature]

[0006] [Non-Patent Document 1] F. FARZANEH, et al., "Broadside Coupler Channels 1 To 10 GHz", Microwaves&RF magazine, pp.68-77, Jan. 2012 Summary of the Invention [Problem to be solved by the invention]

[0007] However, transmission lines fabricated using printed circuit boards generally have a problem in that they have a larger insertion loss than waveguide structures.

[0008] The present invention has been made to solve the above-mentioned conventional problems, and aims to provide a hybrid circuit that uses a printed circuit board and is easy to mass-produce and has low insertion loss, and a Butler matrix equipped with the same. [Means for solving the problem]

[0009] In order to solve the above problem, the hybrid circuit of the present invention is a hybrid circuit (200) comprising a dielectric substrate (10), a first ground conductor portion (11) provided above the dielectric substrate, a second ground conductor portion (12) provided below the dielectric substrate, a first strip conductor (13) formed on the surface of the dielectric substrate, and a second strip conductor (14) formed on the back surface of the dielectric substrate, wherein a first air layer (15) is provided between the dielectric substrate and the first ground conductor portion, and a second air layer (16) is provided between the dielectric substrate and the second ground conductor portion.

[0010] In other words, in the hybrid circuit according to the present invention, the dielectric layer between the dielectric substrate and the first ground conductor and the dielectric layer between the dielectric substrate and the second ground conductor are made of air layers with low dielectric constants and dielectric loss tangents.

[0011] The hybrid circuit according to the present invention configured in this manner can reduce insertion loss while using a printed circuit board that is highly mass-producible.

[0012] Furthermore, the hybrid circuit of the present invention may be configured such that the width of the first strip conductor and the second strip conductor at an intersection (30) where the first strip conductor and the second strip conductor intersect is narrower than the width of the first strip conductor and the second strip conductor at other locations other than the intersection, the thickness of the first air layer facing the first strip conductor at the intersection is thinner than the thickness of the first air layer at other locations other than the intersection where it faces the first strip conductor, and the thickness of the second air layer at the intersection where it faces the second strip conductor is thinner than the thickness of the second air layer at other locations other than the intersection where it faces the second strip conductor.

[0013] With this configuration, the hybrid circuit of the present invention has a structure in which the thickness of the air layer is changed depending on the width of the first strip conductor and the second strip conductor, making it possible to achieve optimal impedance over the entire strip line, including the intersection.

[0014] In addition, the hybrid circuit according to the present invention may further include a metal housing (120) that houses the dielectric substrate on which the first strip conductor and the second strip conductor are formed, and the first ground conductor portion and the second ground conductor portion may be configured to be part of the metal housing.

[0015] With this configuration, the hybrid circuit according to the present invention can easily provide an air layer using a metal housing.

[0016] Furthermore, the Butler matrix according to the present invention may be a Butler matrix including any one of the hybrid circuits described above, wherein the metal housing comprises a lid portion (121) and a main body portion (124), the main body portion has a bottom wall (125) constituting the second ground conductor portion and two side walls (126a, 126b) standing perpendicular to the bottom wall and facing each other, and a plurality of coaxial connectors (128, 129) conductively connected to the first strip conductor or the second strip conductor are attached to the two side walls, and the lid portion has an edge portion (122) that contacts the upper surfaces of the two side walls and a convex portion (123) that fits into the main body portion with a predetermined gap from the two side walls and constitutes the first ground conductor portion, and the depth of the gap may be 40% or less of the wavelength of the maximum frequency in the frequency band used.

[0017] With this configuration, the Butler matrix of the present invention can avoid a drop in insertion loss in the operating frequency band by adjusting the depth of the gap between the lid and the two side walls to 40% or less of the wavelength of the maximum frequency in the operating frequency band.

[0018] Furthermore, the Butler matrix according to the present invention may be configured such that the operating frequency band is 600 MHz to 7.125 GHz. [Effects of the Invention]

[0019] The present invention provides a hybrid circuit that uses a printed circuit board and is highly mass-producible and has low insertion loss, and a Butler matrix that includes the hybrid circuit. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram illustrating an example of a circuit configuration of a Butler matrix according to an embodiment of the present invention. [Figure 2] FIG. 1 is a partial cross-sectional view showing the structure of a Butler matrix according to an embodiment of the present invention. [Figure 3]1A and 1B are cross-sectional views of a transmission line in a Butler matrix according to an embodiment of the present invention. [Figure 4] 1A and 1B are cross-sectional views of a stripline in a Butler matrix according to an embodiment of the present invention and a conventional stripline, and graphs showing the frequency characteristics of the striplines. [Figure 5] 1A and 1B are cross-sectional views of strip lines in a Butler matrix according to an embodiment of the present invention, and a graph showing the relationship between the width of a strip conductor and the thickness of an air layer. [Figure 6] FIG. 1 is a perspective view illustrating a configuration example of a hybrid circuit in a Butler matrix according to an embodiment of the present invention. [Figure 7] 7(a) is a plan view showing the configuration of the front surface of the hybrid circuit of FIG. 6, and FIG. 7(b) is a plan view showing the configuration of the back surface of the hybrid circuit of FIG. 6. [Figure 8] FIG. 7 is a perspective view showing the configuration of a crossing point in the hybrid circuit of FIG. 6. [Figure 9] FIG. 2 is a cross-sectional view showing a structure near an intersection of a Butler matrix according to an embodiment of the present invention. [Figure 10] 7 is a graph showing a simulation result of the return loss of the hybrid circuit of FIG. 6. [Figure 11] 1 is a partial cross-sectional view showing a gap between a lid portion and a main body portion in a Butler Matrix according to an embodiment of the present invention. [Figure 12] 10 is a graph illustrating simulation results showing the effect of the gap depth between the lid and the body on the insertion loss of a Butler matrix according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of a hybrid circuit and a Butler matrix including the same according to the present invention will be described with reference to the drawings. Note that the dimensional ratios of the components in the drawings do not necessarily correspond to the actual dimensional ratios.

[0022] 1 is a diagram showing an example of the circuit configuration of a Butler matrix 100 according to this embodiment. The Butler matrix 100 shown in FIG. 1 is an 8×8 Butler matrix.

[0023] Butler matrix 100 has eight input terminals 1L to 4L and 1R to 4R for inputting signals and eight output terminals 111 to 118 for outputting signals. Butler matrix 100 also has hybrid circuits 201 to 212 (hereinafter simply referred to as "hybrid circuit 200") and phase shifters 301 to 308.

[0024] The Butler matrix 100 distributes input signals from the input terminals 1L to 4L and 1R to 4R to the output terminals 111 to 118 at the same level and with a predetermined phase difference that differs for each input terminal.

[0025] The hybrid circuits 201 to 212 divide a signal input to an input terminal A1 or A2 into two output signals having a phase difference of 90 degrees, and output the two signals from output terminals B1 and B2.

[0026] Phase shifters 301 and 304 shift the phase of the signal passing through them by -67.5°. Phase shifters 302 and 303 shift the phase of the signal passing through them by -22.5°. Phase shifters 305 to 308 shift the phase of the signal passing through them by -45°.

[0027] Furthermore, the input terminals 1L to 4L, 1R to 4R are connected to the hybrid circuits 201 to 204, the hybrid circuits 201 to 204 are connected to the hybrid circuits 205 to 208 or the phase shifters 301 to 304 in the subsequent stages, the hybrid circuits 205 to 208 are connected to the hybrid circuits 209 to 212 or the phase shifters 305 to 308 in the subsequent stages, and the hybrid circuits 209 to 212 are connected to the output terminals 111 to 118 by transmission lines.

[0028] Furthermore, the hybrid circuits 201 to 212 and the phase shifters 301 to 308 are also configured with transmission lines. The transmission lines are, for example, planar lines such as microstrip lines, coplanar lines, or strip lines (triplate lines).

[0029] It is also possible to cut out the bold framed portion of FIG. 1 from the Butler matrix 100 and use it as a 4×4 Butler matrix.

[0030] 2 is a partial cross-sectional view of a Butler matrix 100 including a hybrid circuit 200 according to this embodiment. As shown in FIG. 2, the Butler matrix 100 includes a rectangular parallelepiped metal housing 120 and a printed circuit board 20, with the printed circuit board 20 housed inside the metal housing 120.

[0031] Metal housing 120 is made up of lid 121 and main body 124. Fig. 2 shows a state in which lid 121 is removed from main body 124. Main body 124 has a bottom wall 125 and four side walls 126 that stand perpendicular to bottom wall 125. Of the four side walls 126, two side walls 126a and 126b extend in the width direction (x direction) of metal housing 120 and face each other.

[0032] The lid 121 has an edge 122 that contacts the upper surfaces of the four side walls 126, and a protrusion 123 that fits into the main body 124 with a predetermined gap between it and two side walls 126a, 126b. The lid 121 is fixed to the metal housing 120 with the edge 122 in contact with the upper surfaces of the side walls 126 by screw holes and screws (not shown). For example, the edge 122 is attached to the upper surfaces of the side walls 126 with a conductive adhesive. Alternatively, conductive rubber, a gasket, or the like is placed between the edge 122 and the upper surfaces of the side walls 126 to ensure contact between the edge 122 and the side walls 126.

[0033] The entire metal housing 120 may be made of metal, or at least the bottom wall 125 of the main body 124 and the protrusion 123 of the lid 121 may be made of metal. The metal portion of the metal housing 120 is conductively connected to a high-frequency ground (RF ground). The metal constituting the entire metal housing 120 or the metal portion of the metal housing 120 may be, for example, aluminum, brass, or another metal that is plated with gold or silver.

[0034] A plurality of coaxial connectors 128, 129 are attached to the two side walls 126a, 126b, and are conductively connected to the strip conductors of the printed circuit board 20 fixed on the bottom wall 125 of the metal housing 120, forming input terminals 1L to 4L, 1R to 4R and output terminals 111 to 118.

[0035] The center pins of the coaxial connectors 128, 129 shown in FIG. 2 are conductively connected, for example, by soldering, to first and second strip conductors formed on the printed circuit board 20, which will be described later, to form a coaxial-strip line transition section.

[0036] Coaxial connector 128 is adapted to be connected, for example, via a coaxial cable, to a signal source that outputs a high-frequency signal, while coaxial connector 129 is adapted to be connected, for example, via a coaxial cable, to an antenna of a UE such as a wireless communication terminal.

[0037] Hereinafter, a case where the transmission lines constituting the Butler matrix 100 of this embodiment are strip lines will be described.

[0038] 3(a) and 3(b), the strip line 1 in the Butler matrix 100 includes a dielectric substrate 10, a first ground conductor portion 11 provided above the dielectric substrate 10, a second ground conductor portion 12 provided below the dielectric substrate 10, a first strip conductor 13 formed on the front surface of the dielectric substrate 10, and a second strip conductor 14 formed on the back surface of the dielectric substrate 10. The dielectric substrate 10 on which the first strip conductor 13 and the second strip conductor 14 are formed constitutes a printed circuit board 20.

[0039] A first air layer 15 is provided between the dielectric substrate 10 and the first ground conductor 11, and a second air layer 16 is provided between the dielectric substrate 10 and the second ground conductor 12. In this embodiment, the first air layer 15 and the second air layer 16 have the same thickness. Here, the thickness of the first air layer 15 is the distance between the upper surface of the dielectric substrate 10 and the lower surface of the first ground conductor 11, and the thickness of the second air layer 16 is the distance between the lower surface of the dielectric substrate 10 and the upper surface of the second ground conductor 12.

[0040] In the following description, the first strip conductor 13 and the second strip conductor 14 will also be collectively referred to simply as "strip conductors 13, 14." Furthermore, the first air layer 15 and the second air layer 16 will also be collectively referred to simply as "air layers 15, 16."

[0041] The dielectric substrate 10 is a substrate such as a semiconductor substrate made of GaAs, GaN, InP, or Si, an alumina ceramic substrate, a resin substrate, or a quartz glass substrate. The dielectric substrate 10 may be a substrate made by bonding together a plurality of resin substrates, or may be a single-layer resin substrate. For example, MEGTRON7 (registered trademark) manufactured by Panasonic Corporation can be suitably used as the dielectric substrate 10.

[0042] In this embodiment, the first ground conductor 11 is, for example, a protrusion 123 of a lid 121 of a metal housing 120. On the other hand, the second ground conductor 12 is a bottom wall 125 of a main body 124 of the metal housing 120.

[0043] 4 is a cross-sectional view showing an example of the configuration of the strip line 1 of this embodiment and a conventional strip line 1′, and a graph showing their frequency characteristics. The solid line in the graph shows the transmission coefficient S 21 The dashed line in the graph shows the transmission coefficient S 21 This shows:

[0044] In both configurations of the strip lines 1 and 1', MEGTRON7 (registered trademark) manufactured by Panasonic Corporation, which has a relative permittivity εr of 3.35 and a dielectric loss tangent tanδ of 0.0023, is used as the dielectric substrate and dielectric layer.

[0045] The strip line 1 of the present invention shown in Figure 4 has a dielectric substrate 10 made of MEGTRON7 with a thickness of 0.1 mm, a first ground conductor portion 11 and a second ground conductor portion 12 made of aluminum, a first strip conductor 13 made of copper with a width of 2.20 mm, and air layers 15 and 16 each having a thickness of 0.8 mm.

[0046] On the other hand, in the conventional strip line 1', the dielectric substrate 10' is made of MEGTRON7 with a thickness of 0.1 mm, the first ground conductor portion 11' and the second ground conductor portion 12' are made of copper, the first strip conductor 13' is made of copper with a width of 1.02 mm, and the dielectric layers 15' and 16' above and below the dielectric substrate 10' are made of MEGTRON7 with a thickness of 0.8 mm.

[0047] As shown in the graph in Figure 4, the difference in insertion loss between the strip line 1 of the present invention and the conventional strip line 1' increases as the frequency increases, which shows that the structure of the strip line 1 of the present invention, which includes an air layer, becomes more advantageous as the frequency increases.

[0048] In the configuration disclosed in Non-Patent Document 1, in order to obtain an appropriate degree of coupling at the crossover between two strip conductors, the width of each strip conductor is made narrower than that of a 50 Ω line in part. As a result, the configuration disclosed in Non-Patent Document 1 has the problem of increased reflection and reduced design freedom.

[0049] Fig. 5 is a graph showing the relationship between the width w of the strip conductors 13 and 14 and the thickness t of the air layers 15 and 16 when configuring the strip line 1 of the present invention as a 50 Ω line. Here, MEGTRON7, which has a relative permittivity εr of 3.35, a dielectric loss tangent tanδ of 0.0023, and a thickness of 0.3 mm, is used as the dielectric substrate 10. Note that the cross-sectional view of Fig. 5 shows only the portion of the strip line 1 where the first strip conductor 13 is provided.

[0050] As shown in the graph of FIG. 5, the relationship between the width w of the strip conductors 13 and 14 and the thickness t of the air layers 15 and 16 is expressed by the following equation (1).

[0051] t=0.0042w 2 +0.335w+0.0235 (1)

[0052] From the graph of FIG. 5 and equation (1), it can be seen that in order to set the impedance of the strip line 1 to 50Ω, it is necessary to change the thickness t of the air layers 15 and 16 in accordance with the width w of the strip conductors 13 and .

[0053] Fig. 6 is a diagram showing an example of the configuration of a hybrid circuit 200 in which the impedance is adjusted to 50 Ω. As already mentioned, the hybrid circuit 200, which constitutes a part of the Butler matrix 100, includes a metal housing 120 and a dielectric substrate 10. However, in Fig. 6, the dielectric substrate 10 is not shown, and only the bottom wall 125 of the metal housing 120 is shown.

[0054] 7(a) is a diagram showing a dielectric substrate 10 and a first strip conductor 13 formed on the front surface of the dielectric substrate 10 in a hybrid circuit 200. FIG. 7(b) is a diagram showing a dielectric substrate 10 and a second strip conductor 14 formed on the rear surface of the dielectric substrate 10 in a hybrid circuit 200.

[0055] The strip conductors 13 and 14 in the hybrid circuit 200 intersect at an intersection 30, which is shown surrounded by a dashed ellipse in Figures 7(a) and 7(b). An enlarged view of the intersection 30 is shown in Figure 8. The dielectric substrate 10 is not shown in Figure 8.

[0056] The width of the strip conductors 13 and 14 at the intersection 30 is narrower than the width of the strip conductors 13 and 14 at other locations than the intersection 30. This is to obtain an appropriate degree of coupling between the strip conductors 13 and 14.

[0057] Fig. 9 is a cross-sectional view of the vicinity of the intersection 30 of the hybrid circuit 200. As shown in Fig. 9, the thickness tc of the first air layer 15 at the intersection 30, which faces the first strip conductor 13, is thinner than the thickness of the first air layer 15 at the other parts of the first air layer 15 other than the intersection 30, which faces the first strip conductor 13.

[0058] Similarly, the thickness tc of the portion of the second air layer 16 facing the second strip conductor 14 at the intersection 30 is thinner than the thickness of the portion of the second air layer 16 other than the portion facing the second strip conductor 14 at the intersection 30.

[0059] In other words, the hybrid circuit 200 is configured to adjust the thickness of the air layers 15 and 16 by gradually changing the height of the convex portion 123 of the lid portion 121 of the metal casing 120 and the bottom wall 125 of the main body portion 124 in stages in accordance with the gradually changing width of the strip conductors 13 and 14.

[0060] In this way, by gradually changing the width of the strip conductors 13 and 14 and the thickness of the air layers 15 and 16 in a stepwise manner, the impedance of the strip line 1 at the intersection 30 and other locations is matched to, for example, 50 Ω. With this structure, the reflection loss at the intersection 30 can be reduced.

[0061] FIG. 10 shows the reflection coefficient S of the hybrid circuit 200. 11 10 is a graph showing the simulation results of the reflection coefficient S when the thickness of the air layers 15 and 16 is adjusted to set the impedance of the strip line 1 to 50 Ω. 11 The dashed line shows the reflection coefficient S when the thickness of the air layers 15 and 16 is not adjusted. 11 is.

[0062] In this simulation, the dielectric substrate 10 made of the above-mentioned MEGTRON7 has a thickness of 0.3 mm, the width of the strip conductors 13, 14 at the intersection 30 is 0.3 mm, and the width of the strip conductors 13, 14 next to the intersection 30 is 1.2 mm. The thickness tc of the air layers 15, 16 at the point where the width of the strip conductors 13, 14 is 0.3 mm is 0.124 mm, and the thickness of the air layers 15, 16 at the point where the width of the strip conductors 13, 14 is 1.2 mm is 0.432 mm.

[0063] From the simulation results of FIG. 10, by adjusting the thickness of the air layers 15 and 16 to set the impedance of the strip line 1 constituting the hybrid circuit 200 to 50Ω, the reflection coefficient S 11 It can be seen that becomes smaller.

[0064] As already mentioned, when the protrusion 123 of the lid portion 121 is fitted into the main body portion 124, a gap g due to mechanical tolerances is generated between the protrusion 123 and the side wall 126 as shown in Fig. 11. In particular, the gap g between the protrusion 123 and the side walls 126a, 126b to which the coaxial connectors 128, 129 are attached functions as a band rejection filter, and therefore the depth gl of the gap g, i.e., the length in the vertical direction (z direction) along the side walls 126a, 126b, needs to be shortened according to the frequency band used.

[0065] Permeability coefficient S due to the depth g of the gap g 21 The change in the capacitance was confirmed by simulation, and the results are shown in Fig. 12. The simulation model here includes the coaxial connector 128 and the strip line connecting the center pin of the coaxial connector 128 to the first strip conductor 13 or the second strip conductor 14 of the hybrid circuit 200. The width of the gap g in the direction perpendicular to the side walls 126a and 126b (y direction) is set to 0.5 mm.

[0066] According to the simulation results in Figure 12, when gl = 15 mm, the transmission coefficient S 21 In addition, when gl=20 mm, the transmission coefficient S 21 There is a decline in the number of cases.

[0067] The simulation results show that a drop occurs when the depth gl of the gap g is about 40% of the wavelength of the frequency used. Therefore, in the Butler matrix 100, the depth gl of the gap g needs to be 40% or less of the wavelength of the maximum frequency of the frequency band used. Here, the frequency band used is, for example, 600 MHz to 7.125 GHz, which is the frequency band of FR1 (Frequency Range 1) used in 5G NR.

[0068] As described above, in the hybrid circuit 200 according to this embodiment and the Butler matrix 100 including it, the dielectric layer between the dielectric substrate 10 and the first ground conductor portion 11 and the dielectric layer between the dielectric substrate 10 and the second ground conductor portion 12 are made up of air layers 15, 16 with low dielectric constant and dielectric loss tangent.

[0069] The hybrid circuit 200 according to this embodiment configured as described above and the Butler matrix 100 including the hybrid circuit 200 can reduce insertion loss while using a printed circuit board 20 that is highly mass-producible.

[0070] In addition, the hybrid circuit 200 of this embodiment and the Butler matrix 100 equipped with it have a structure in which the thickness of the air layers 15, 16 is changed depending on the width of the first strip conductor 13 and the second strip conductor 14, thereby realizing optimal impedance throughout the entire strip line 1 including the intersection 30.

[0071] Furthermore, the hybrid circuit 200 of this embodiment and the Butler matrix 100 equipped with it can easily provide air layers 15, 16 by configuring the first ground conductor portion 11 and the second ground conductor portion 12 as part of the metal housing 120.

[0072] In addition, in the Butler matrix 100 including the hybrid circuit 200 according to this embodiment, the depth of the gap between the convex portion 123 of the lid portion 121 and the two side walls 126a, 126b is 40% or less of the wavelength of the maximum frequency in the frequency band used.

[0073] The Butler matrix 100 according to this embodiment configured as above has a transmission coefficient S 21 This can avoid a decline in sales. [Explanation of symbols]

[0074] 1. Stripline 10 Dielectric substrate 11 First ground conductor portion 12 Second ground conductor part 13 First strip conductor 14 Second strip conductor 15 First Air Layer 16 Second Air Layer 20 Printed circuit board 30 Intersection 100 Butler Matrix 111~118 Output terminals 120 Metal Case 121 Lid 122 Edge 123 Convex 124 Main body 125 bottom wall 126,126a,126b side wall 128,129 Coaxial Connectors 200, 201-212 Hybrid circuit 301~308 Phase shifter 1L~4L, 1R~4R input terminals

Claims

1. A dielectric substrate (10); a first ground conductor portion (11) provided above the dielectric substrate; a second ground conductor portion (12) provided below the dielectric substrate; a first strip conductor (13) formed on the surface of the dielectric substrate; A hybrid circuit (200) comprising: a second strip conductor (14) formed on the back surface of the dielectric substrate; A hybrid circuit characterized in that a first air layer (15) is provided between the dielectric substrate and the first ground conductor portion, and a second air layer (16) is provided between the dielectric substrate and the second ground conductor portion.

2. The widths of the first strip conductor and the second strip conductor at an intersection (30) where the first strip conductor and the second strip conductor intersect are narrower than the widths of the first strip conductor and the second strip conductor at a location other than the intersection, a thickness of the first air layer at the intersection facing the first strip conductor is thinner than a thickness of the first air layer at a portion other than the intersection facing the first strip conductor; 2. The hybrid circuit according to claim 1, wherein the thickness of the second air layer at the intersection facing the second strip conductor is thinner than the thickness of the second air layer at other portions of the second air layer other than the intersection facing the second strip conductor.

3. The antenna further includes a metal housing (120) that houses the dielectric substrate on which the first strip conductor and the second strip conductor are formed, 3. The hybrid circuit according to claim 1, wherein the first ground conductor portion and the second ground conductor portion are formed as part of the metal housing.

4. A Butler matrix comprising the hybrid circuit of claim 1 or 2.

5. A Butler matrix comprising the hybrid circuit of claim 3, The metal housing comprises a lid portion (121) and a main body portion (124), The main body portion has a bottom wall (125) that constitutes the second ground conductor portion, and two side walls (126a, 126b) that are erected perpendicular to the bottom wall and opposed to each other, a plurality of coaxial connectors (128, 129) are attached to the two side walls and are conductively connected to the first strip conductor or the second strip conductor; the lid portion has an edge portion (122) that contacts the upper surfaces of the two side walls, and a protrusion (123) that fits into the body portion with a predetermined gap between it and the two side walls and that constitutes the first ground conductor portion, A Butler matrix characterized in that the depth of the gap is 40% or less of the wavelength of the maximum frequency in the frequency band used.

6. 6. The Butler Matrix according to claim 5, wherein the frequency band used is 600 MHz to 7.125 GHz.

Images