Output matching circuit

Abstract

This output matching circuit electrically connects a digital phase-shift circuit and an output transmission line. The digital phase-shift circuit has a circuit-side signal line, a first line, a second line including a loop line, a first grounded conductor, a second grounded conductor, a first electronic switch, and a second electronic switch. The output transmission line has an output-side signal line and an output-side grounded conductor. The output matching circuit comprises a signal line connected to the circuit-side signal line and the output-side signal line, and a return line electrically connected to the second grounded conductor and the output-side grounded conductor. The return line is longer than the signal line.

Description

Output matching circuit

[0001] This application claims priority from Japanese Patent Application No. 2023-137590, filed on August 25, 2023, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 below discloses a digitally controlled digital phase shift circuit for microwave, quasi-millimeter wave, or millimeter wave applications. As shown in FIG. 1 of Patent Document 1, this digital phase shift circuit includes a signal line, a first line including a first parallel line, a second line including a second parallel line, a first ground conductor, a second ground conductor, a first electronic switch, and a second electronic switch. The first parallel line and the second parallel line are provided on both sides of the signal line. The second line includes a loop line extending from a first end of the second parallel line to near the second end of the second parallel line. The loop line has a convex shape extending away from the signal line. The first ground conductor is connected to the first end of the first parallel line and the first end of the second parallel line. The second ground conductor is connected to the first end of the second line. The first electronic switch is provided between the second end of the first parallel line and the second ground conductor. A second electronic switch is provided between the second end of the second parallel line and the second ground conductor.

[0003] In such a digital phase shift circuit, a return current flowing through a pair of parallel lines (first and second parallel lines) or a loop line due to transmission of a signal wave through the signal line is switched depending on whether a pair of electronic switches (first and second electronic switches) are open or closed. This causes the operation mode of the digital phase shift circuit to switch between a low delay mode and a high delay mode. That is, the operation mode of the digital phase shift circuit is the low delay mode when a return current flows through the pair of parallel lines, and the high delay mode when a return current flows through the loop line.

[0004] Furthermore, this digital phase shift circuit has a configuration in which a return current flows through a loop line in high delay mode. This allows the inductance value in high delay mode to be increased without excessively increasing the size of the digital phase shift circuit, and the difference (amount of phase shift) between the phase in low delay mode and the phase in high delay mode can be sufficiently increased. In other words, this digital phase shift circuit has the advantage of being both compact and able to increase the difference between the phase in low delay mode and the phase in high delay mode. This digital phase shift circuit may be used connected to an output transmission line composed of multiple conductors.

[0005] Japanese Patent No. 7314385

[0006] However, when the above-mentioned digital phase shift circuit is miniaturized, the spacing between conductors becomes smaller, which increases parasitic capacitance, making it difficult to match the input / output impedance to a real load. A commonly known method for matching the input / output impedance to a real load is to connect an inductor in series with the output unit. However, the above-mentioned digital phase shift circuit (output unit) is composed of multiple conductors. This makes it difficult to connect an inductor, which is a lumped element, in series between the digital phase shift circuit composed of multiple conductors and the output transmission line also composed of multiple conductors.

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an output matching circuit that can match input and output impedances to a real load even when a digital phase shift circuit and an output transmission line are configured with multiple conductors.

[0008] In order to solve the above-described problems, an output matching circuit according to a first aspect of the present invention electrically connects a digital phase shift circuit and an output transmission line, and the digital phase shift circuit includes a circuit-side signal line, a first line including a first parallel line extending parallel to the circuit-side signal line, a second parallel line extending parallel to the circuit-side signal line, and a second line including a loop-shaped loop line extending from a first end of the second parallel line to near a second end of the second parallel line and having a convex shape in a direction away from the circuit-side signal line in an intersecting direction intersecting a longitudinal direction of the circuit-side signal line, a first ground conductor electrically connected to the first end of the first parallel line and the first end of the second parallel line, and a second ground conductor connected to a first end of two parallel lines, a first electronic switch provided between a second end of the first parallel line and the second ground conductor, and a second electronic switch provided between a second end of the second parallel line and the second ground conductor, wherein the circuit-side signal line is located between the first parallel line and the second parallel line in the digital phase shift circuit, and the output transmission line has an output-side signal line and an output-side ground conductor, and the output matching circuit comprises a signal line connected to the circuit-side signal line and the output-side signal line, and a return line electrically connected to the second ground conductor and the output-side ground conductor, and the return line is longer than the signal line.

[0009] According to the first aspect of the present invention, the output matching circuit is configured with a plurality of conductor lines. As a result, even if the digital phase shift circuit and the output transmission line are configured with a plurality of conductors, the output matching circuit can be easily connected in series between them as an inductance component, thereby enabling matching of input and output impedances to a real load.

[0010] A second aspect of the present invention is the output matching circuit of the first aspect, wherein the cross-sectional area of ​​the return line is smaller than the cross-sectional area of ​​the loop line.

[0011] A third aspect of the present invention is the output matching circuit of the first or second aspect, wherein the return line has a loop shape that is convex in the direction away from the signal line in the crossing direction.

[0012] A fourth aspect of the present invention is the output matching circuit of the third aspect, wherein the return line includes, in a plan view, a first intersecting line extending from near a first end of the signal line so as to move away from the signal line in the intersecting direction, a parallel line extending from the first end of the first intersecting line in parallel to the signal line, and a second intersecting line extending from the first end of the parallel line so as to move closer to the signal line in the intersecting direction.

[0013] A fifth aspect of the present invention relates to the output matching circuit of the third aspect, wherein the return line includes, in a plan view, a first intersecting line extending from near a first end of the signal line so as to move away from the signal line in the intersecting direction; a parallel line extending from the first end of the first intersecting line in parallel to the signal line and having a length shorter than that of the signal line; and a bent line connected to the first end of the parallel line, extending a length shorter than that of the first intersecting line so as to move closer to the signal line in the intersecting direction, and then extending parallel to the signal line so as to move away from the first intersecting line.

[0014] A sixth aspect of the present invention is the output matching circuit of any one of the third to fifth aspects, wherein the cross-sectional area of ​​at least a part of the return line is smaller than the cross-sectional area of ​​the signal line.

[0015] Furthermore, aspect 7 of the present invention is an output matching circuit according to any one of aspects 3 to 6, wherein the return line includes a first return line section formed on a first layer, and a second return line section electrically connected to the first return line section through a via and formed on a second layer different from the first layer, wherein the first return line section and the second return line section form a single loop and are arranged so that only their ends overlap in a planar view, and the ends are electrically connected through the via.

[0016] According to the above aspects of the present invention, it is possible to provide an output matching circuit that can match input and output impedances to a real load even when the digital phase shift circuit and the output transmission line are configured with a plurality of conductors.

[0017] 12 is a plan view showing a digital phase shift circuit, an output matching circuit, and an output transmission line according to a first embodiment of the present invention. It is a cross-sectional view taken along line II-II in FIG. 1. It is a cross-sectional view taken along line III-III in FIG. 1. It is a cross-sectional view taken along line IV-IV in FIG. 1. It is a cross-sectional view taken along line V-V in FIG. 1. It is a plan view showing a digital phase shift circuit, an output matching circuit, and an output transmission line according to a second embodiment of the present invention. It is a plan view showing a digital phase shift circuit, an output matching circuit, and an output transmission line according to a third embodiment of the present invention. It is a plan view showing a digital phase shift circuit, an output matching circuit, and an output transmission line according to a fourth embodiment of the present invention. It is a perspective view showing a portion of a return line according to a fourth embodiment of the present invention. It is a plan view showing a digital phase shift circuit, an output matching circuit, and an output transmission line according to a fifth embodiment of the present invention. It is a perspective view showing a portion of a return line according to the fourth embodiment of the present invention. It is a plan view showing a portion of an output matching circuit and an output transmission line according to a first modified example of the present invention. It is a cross-sectional view taken along line XIII-XIII in FIG. It is a cross-sectional view taken along line XIV-XIV in FIG. 16. A plan view showing a part of an output matching circuit and a part of an output transmission line according to a second modified example of the present invention. A plan view showing a part of an output matching circuit and a part of an output transmission line according to a third modified example of the present invention. A cross-sectional view taken along line XVII-XVII shown in FIG. 16. A plan view showing a part of an output matching circuit and a part of an output transmission line according to a fourth modified example of the present invention. A cross-sectional view taken along line XIX-XIX shown in FIG. 18. A plan view showing a part of a digital phase shift circuit, an output matching circuit, and an output transmission line according to a fifth modified example of the present invention. A cross-sectional view taken along line XXI-XXI shown in FIG. 20. A plan view showing a part of an output matching circuit and a part of an output transmission line according to a sixth modified example of the present invention. A cross-sectional view taken along line XXIII-XXIII shown in FIG. 22. A plan view showing a part of an output matching circuit and a part of an output transmission line according to a seventh modified example of the present invention. A cross-sectional view taken along line XXV-XXV shown in FIG. 24.

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] 1 is a plan view showing a digital phase shift circuit B, an output matching circuit 100, and an output transmission line 90 according to a first embodiment of the present invention. Hereinafter, the digital phase shift circuit B, the output matching circuit 100, and the output transmission line 90 may be collectively referred to as a "connection structure A."

[0020] The digital phase shift circuit B is a high-frequency circuit that receives a high-frequency signal such as a microwave, quasi-millimeter wave, or millimeter wave as input and outputs a high-frequency signal that has been phase-shifted by a predetermined amount to the outside. The output transmission line 90 serves to transmit the high-frequency signal that has been phase-shifted in the digital phase shift circuit B to the outside of the connection structure A.

[0021] The output matching circuit 100 electrically connects the digital phase shift circuit B and the output transmission line 90. The output matching circuit 100 has a role of transmitting the high-frequency signal input from the digital phase shift circuit B to the output transmission line 90. As will be described in detail later, the output matching circuit 100 also has a role of matching the input and output impedances to a real load.

[0022] In the following, first, a detailed description will be given of the digital phase shift circuit B and the output transmission line 90 to which the output matching circuit 100 is connected, followed by a detailed description of the output matching circuit 100.

[0023] <Digital Phase Shift Circuit> Fig. 2 is a cross-sectional view taken along line II-II shown in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III shown in Fig. 1. Fig. 4 is a cross-sectional view taken along line IV-IV shown in Fig. 1.

[0024] 1 , the digital phase shift circuit B includes a signal line (circuit-side signal line) 10, a first line 21, a second line 22, an upper pad 24, an upper pad 25, a first ground conductor 31, and a second ground conductor 32. The first line 21 according to this embodiment includes a first parallel line 21p1 and a pair of upper pads 21d1 and 21d2. The second line 22 according to this embodiment includes a second parallel line 22p2, a first intersecting line 22c1, a third parallel line 22p3, a bent line 22b, a second intersecting line 22c2, and a pair of upper pads 22d1 and 22d2. In addition, the digital phase shift circuit B of this embodiment includes four electronic switches 41 to 44, a plurality of connecting conductors 50, a capacitor 60, a plurality of connecting pads P1 to P4, and a switch control unit 80 (control circuit) (see also Figures 2 and 3).

[0025] As shown in Fig. 1, the signal line 10 is a linear strip-shaped conductor extending in one direction. That is, the signal line 10 is a long, plate-like conductor having a constant width, a constant thickness, and a predetermined length. A signal current flows through the signal line 10 from the left side to the right side of the paper in Fig. 1, that is, from the end on the left side (input end) to the end on the right side (output end). This signal current is a high-frequency signal having a wavelength in the microwave, quasi-millimeter wave, or millimeter wave range described above.

[0026] (Direction Definition) In this embodiment, the longitudinal direction of the signal line 10 (the direction in which the signal line 10 extends) is simply referred to as the longitudinal direction X. The direction from the input end to the output end of the signal line 10 along the longitudinal direction X is referred to as the +X direction or rightward. The direction opposite to the rightward is referred to as the leftward or −X direction. The direction intersecting (e.g., perpendicular to) the signal line 10 is referred to as the cross direction Y. One direction along the cross direction Y is referred to as the back side or +Y direction. The direction opposite to the back side is referred to as the front side or −Y direction. The direction intersecting (e.g., perpendicular to) both the longitudinal direction X and the cross direction Y is referred to as the up-down direction Z. One direction along the up-down direction Z is referred to as the up-down or +Z direction. The direction opposite to the up-down direction is referred to as the down-down or −Z direction. A view from the up-down direction Z is referred to as a planar view. Note that the up-down direction Z does not have to coincide with the vertical direction. Furthermore, "upper" and "lower" do not have to coincide with the upper and lower sides in the vertical direction. Furthermore, instead of defining the +X direction and the -X direction as the right and left, respectively, the +X direction and the -X direction may be defined as the left and right, respectively.

[0027] The signal line 10 electrically has an inductance L1 as a lumped constant circuit element. This inductance L1 is a parasitic inductance whose magnitude depends on the shape of the signal line 10, such as the length of the signal line 10. The signal line 10 also electrically has a capacitance C1 as a lumped constant circuit element. This capacitance C1 is a parasitic capacitance between the signal line 10 and a first parallel line 21p1 (described in detail below), between the signal line 10 and a second parallel line 22p2 (described in detail below), between the signal line 10 and a third parallel line 22p3 (described in detail below), or between the signal line 10 and a silicon substrate (not shown), for example.

[0028] In the following description, one side in the Y direction (+Y side) of the signal line 10 will be referred to as the first side of the signal line 10, and the other side in the Y direction (-Y side) of the signal line 10 will be referred to as the second side of the signal line 10. The first parallel line 21p1 is a linear, strip-shaped conductor provided on the second side (-Y side) of the signal line 10. The first parallel line 21p1 is a long, plate-shaped conductor with a constant width, constant thickness, and a predetermined length. The first parallel line 21p1 extends parallel to the signal line 10 (longitudinal direction X). The first parallel line 21p1 and the signal line 10 are spaced apart in the intersecting direction Y. Of the ends of the first parallel line 21p1, the end located on the -X side will be referred to as the first end (one end), and the end located on the +X side will be referred to as the second end (the other end). Of the first parallel lines 21p1, the edge located on the +Y side is referred to as the first edge (one side edge), and the edge located on the -Y side is referred to as the second edge (the other side edge).

[0029] The upper pad 21d1 is a rectangular flat conductor connected to the first end (-X side) of the first parallel line 21p1. The long sides of the upper pad 21d1 extend in the transverse direction Y, and the short sides of the upper pad 21d1 extend in the longitudinal direction X. Of the short sides of the upper pad 21d1, the short side located on the +Y side is referred to as the first short side (one short side), and the short side located on the -Y side is referred to as the second short side (other short side). The first short side (+Y side) of the upper pad 21d1 is located at approximately the same position in the transverse direction Y as the first side edge (+Y side) of the first parallel line 21p1. The second short side (-Y side) of the upper pad 21d1 is located closer to the front (-Y side) than the second side edge (-Y side) of the first parallel line 21p1. That is, the dimension of the upper pad 21d1 in the cross direction Y is larger than the width (dimension in the cross direction Y) of the first parallel line 21p1.

[0030] The upper pad 21d2 is a rectangular flat conductor connected to the second end (+X side) of the first parallel line 21p1. The long sides of the upper pad 21d2 extend in the transverse direction Y, and the short sides of the upper pad 21d2 extend in the longitudinal direction X. Of the short sides of the upper pad 21d2, the short side located on the +Y side is referred to as the first short side (one short side), and the short side located on the -Y side is referred to as the second short side (other short side). The first short side (+Y side) of the upper pad 21d2 is located at approximately the same position in the transverse direction Y as the first side edge (+Y side) of the first parallel line 21p1. The second short side (-Y side) of the upper pad 21d2 is located closer to the front (-Y side) than the second side edge (-Y side) of the first parallel line 21p1. That is, the dimension of the upper pad 21d2 in the cross direction Y is larger than the width (dimension in the cross direction Y) of the first parallel line 21p1.

[0031] The second parallel line 22p2 is a linear strip-shaped conductor provided on a first side (+Y side) of the signal line 10. The second parallel line 22p2 is a long, plate-shaped conductor having a constant width, a constant thickness, and a predetermined length. The second parallel line 22p2 extends parallel to the signal line 10 (longitudinal direction X). The second parallel line 22p2 and the signal line 10 are spaced apart in the cross direction Y. Of the ends of the second parallel line 22p2, the end located on the −X side is referred to as the first end (one end), and the end located on the +X side is referred to as the second end (the other end). Of the side edges of the second parallel line 22p2, the edge located on the +Y side is referred to as the first side edge (one side edge), and the edge located on the −Y side is referred to as the second side edge (the other side edge).

[0032] The second parallel line 22p2 is provided on the opposite side of the signal line 10 from the first parallel line 21p1. In other words, the second parallel line 22p2 is disposed so that the signal line 10 is located between the first parallel line 21p1 and the second parallel line 22p2 in the cross direction Y.

[0033] The upper pad 22d1 is a rectangular flat conductor connected to the first end (-X side) of the second parallel line 22p2. The long sides of the upper pad 22d1 extend in the transverse direction Y, and the short sides of the upper pad 22d1 extend in the longitudinal direction X. Of the short sides of the upper pad 22d1, the short side located on the +Y side is referred to as the first short side (one short side), and the short side located on the -Y side is referred to as the second short side (other short side). The second short side (-Y side) of the upper pad 22d1 is located at approximately the same position in the transverse direction Y as the second side edge (-Y side) of the second parallel line 22p2. The first short side (+Y side) of the upper pad 22d1 is located further back (+Y side) than the first side edge (+Y side) of the second parallel line 22p2. That is, the dimension of the upper pad 22d1 in the cross direction Y is larger than the width (dimension in the cross direction Y) of the second parallel line 22p2.

[0034] The upper pad 22d2 is a rectangular flat conductor connected to the second (+X side) of the second parallel line 22p2. The long sides of the upper pad 22d2 extend in the transverse direction Y, and the short sides of the upper pad 22d2 extend in the longitudinal direction X. Of the short sides of the upper pad 22d2, the short side located on the +Y side is referred to as the first short side (one short side), and the short side located on the -Y side is referred to as the second short side (other short side). The second short side (-Y side) of the upper pad 22d2 is located at approximately the same position in the transverse direction Y as the second side edge (-Y side) of the second parallel line 22p2. The first short side (+Y side) of the upper pad 22d2 is located further back (+Y side) than the first side edge (+Y side) of the second parallel line 22p2. That is, the dimension of the upper pad 22d2 in the cross direction Y is larger than the width (dimension in the cross direction Y) of the second parallel line 22p2.

[0035] The first crossing line 22c1 is a strip-shaped conductor electrically connected to a first end (-X side) of the second parallel line 22p2. The first crossing line 22c1 has a bent portion CR1, and the side closer to the second parallel line 22p2 (e.g., closer to the second parallel line 22p2 than the midpoint of the first crossing line 22c1 in the Y direction) has a crank shape. In a plan view, the first crossing line 22c1 extends from the first end (-X side) of the second parallel line 22p2, away from the signal line 10 in the crossing direction Y, bends to the right (+X side) at the bent portion CR1, and then extends again away from the signal line 10 in the crossing direction Y. The end of the first crossing line 22c1 located on the +Y side is referred to as the first end (one end), and the end located on the -Y side is referred to as the second end (the other end). The second end of the first intersecting line 22c1 is also the second end of a loop line RP (described later).

[0036] The third parallel line 22p3 is a linear strip-shaped conductor connected to the first end (+Y end) of the first intersecting line 22c1. The third parallel line 22p3 is a long, plate-shaped conductor having a constant width, constant thickness, and predetermined length. The third parallel line 22p3 extends from the first end (+Y side) of the first intersecting line 22c1 in a direction parallel to the signal line 10 (longitudinal direction X). That is, in this embodiment, the third parallel line 22p3 extends from the first end (+Y side) of the first intersecting line 22c1 toward the right (+X side). The length of the third parallel line 22p3 is shorter than the length of the second parallel line 22p2. Of the ends of the third parallel line 22p3, the end located on the +X side is referred to as the first end (one end), and the end located on the -X side is referred to as the second end (the other end).

[0037] The third parallel line 22p3 is provided on the first side (+Y side) of the signal line 10, at a position farther from the signal line 10 than the second parallel line 22p2. In other words, the third parallel line 22p3 is disposed such that the second parallel line 22p2 is located between the signal line 10 and the third parallel line 22p3 in the cross direction Y.

[0038] As shown in FIG. 1, in the cross direction Y, the distance D1 between the center line of the second parallel line 22p2 and the center line of the third parallel line 22p3 is greater than the distance D2 between the center line of the second parallel line 22p2 and the far outer edge (the outer edge on the third parallel line 22p3 side) of the first ground conductor 31 (described later).

[0039] The bent line 22b is a strip-shaped conductor connected to the first end (+X side) of the third parallel line 22p3 and having a bend CR. The bent line 22b is composed of a first partial line 22b1 and a second partial line 22b2. The first partial line 22b1 extends from the first end (+X side) of the third parallel line 22p3 toward the signal line 10 in the cross direction Y. The end of the first partial line 22b1 located on the -Y side is referred to as the first end (one end), and the end located on the +Y side is referred to as the second end (the other end). The second partial line 22b2 extends from the first end (-Y side) of the first partial line 22b1 toward the longitudinal direction X (right side (+X side)) parallel to the signal line 10. Of the ends of the second line segment 22b2, the end located on the +X side is referred to as the first end (one end), and the end located on the −X side is referred to as the second end (the other end). The line segments 22b1 and 22b2 constituting the bent line 22b are each a long, plate-like conductor having a constant width, a constant thickness, and a predetermined length. The length of the first line segment 22b1 is shorter than the length of the first cross line 22c1. The bent line 22b may have multiple bends CR. In this embodiment, the first end of the second line segment 22b2 is the first end (one end) of the bent line 22b, and the second end of the first line segment 22b1 is the second end (the other end) of the bent line 22b.

[0040] The second crossing line 22c2 is a strip-shaped conductor connected to a first end (+X side) of the second partial line 22b2 constituting the bent line 22b. The second crossing line 22c2 has a bend CR2, and the side closer to the second parallel line 22p2 (e.g., closer to the second parallel line 22p2 than the midpoint of the second crossing line 22c2 in the Y direction) is crank-shaped. In a plan view, the second crossing line 22c2 extends from the first end (+X side) of the partial line 22b2 constituting the bent line 22b toward the signal line 10 in the crossing direction Y, bends to the right (+X side) at the bend CR2, and then extends again toward the signal line 10 in the crossing direction Y. The end of the second crossing line 22c2 located on the −Y side is referred to as the first end (one end), and the end located on the +Y side is referred to as the second end (the other end). The first end of the second intersecting line 22c2 is also the first end of a loop line RP (described later).

[0041] In this embodiment, the first edge (-Y side) of the second intersecting line 22c2 is located at approximately the same position in the intersecting direction Y as the second short sides (-Y side) of the upper pads 22d1 and 22d2 and the second side edge (-Y side) of the second parallel line 22p2. The upper pad 22d2 and the second intersecting line 22c2 are spaced apart from each other in the longitudinal direction X.

[0042] In addition, in this embodiment, a first end (-Y side) of the second cross line 22c2 is constantly electrically connected to a second ground conductor 32 (described later) via a conductor (not shown). In other words, a first end of the loop line RP (described later) is constantly electrically connected to the second ground conductor 32 via a conductor (not shown).

[0043] The first intersecting line 22c1, the third parallel line 22p3, the bent line 22b, and the second intersecting line 22c2 described above form a loop line RP that is convex toward the rear (+Y side). The loop line RP extends so as to at least partially overlap with the second parallel line 22p2 when viewed from the intersecting direction Y. For example, the third parallel line 22p3 according to this embodiment extends in the longitudinal direction X so as to overlap with the second parallel line 22p2 when viewed from the intersecting direction Y.

[0044] The loop line RP is formed on a layer different from the layer on which the signal line 10, the first line 21, the second parallel line 22p2, and the upper pads 22d1, 22d2, 24, and 25 are formed, and the layer on which the first ground conductor 31 and the second ground conductor 32 are formed. For example, the loop line RP is formed on the layer on which the second intermediate pads 71b, 72b, 73b, and 74b (details will be described later) shown in Figures 2 and 3 are formed. The loop line RP may also be formed on the layer on which the third intermediate pads 71c, 72c, 73c, and 74c (details will be described later) shown in Figures 2 and 3 are formed.

[0045] The loop line RP is formed in such a layer in order to make the thickness (cross-sectional area) of the loop line RP smaller than the thickness (cross-sectional area) of the signal line 10, the first line 21, the second parallel line 22p2, and the upper pads 22d1 and 22d2. Generally, in a semiconductor with a multilayer structure, the thickness of the wiring decreases from the surface to the inner layer. Therefore, in this embodiment, the loop line RP is formed in a layer (inner layer) below the layer in which the signal line 10, the first line 21, the second parallel line 22p2, and the upper pads 22d1, 22d2, 24, and 25 are formed, thereby making the thickness (cross-sectional area) of the loop line RP smaller than the thickness (cross-sectional area) of the signal line 10, the first line 21, the second parallel line 22p2, and the upper pads 22d1 and 22d2.

[0046] As will be described in detail later, the thickness of the loop line RP is made smaller than the thicknesses of the signal line 10, the first line 21, the second parallel line 22p2, and the upper pads 22d1 and 22d2 in order to increase the strength of the magnetic field generated by the current (third return current) flowing through the loop line RP and to increase the resistance of the loop line RP. The thickness of the loop line RP is desirably set so that the cross-sectional area of ​​the loop line RP is less than one-fifth the cross-sectional areas of the signal line 10, the first line 21, the second parallel line 22p2, and the upper pads 22d1 and 22d2.

[0047] As shown in FIG. 1 , the upper pad 24 is a rectangular flat conductor similar to the upper pads 21d1 and 21d2 that form part of the first line 21. The long sides of the upper pad 24 extend in the transverse direction Y, and the short sides of the upper pad 24 extend in the longitudinal direction X. Of the short sides of the upper pad 24, the short side located on the +Y side is referred to as the first short side (one short side), and the short side located on the -Y side is referred to as the second short side (other short side). The first short side (+Y side) of the upper pad 24 is located at approximately the same position in the transverse direction Y as the first side edge (+Y side) of the first parallel line 21p1. The second short side (-Y side) of the upper pad 24 is located closer to the front (-Y side) than the second side edge (-Y side) of the first parallel line 21p1. That is, the dimension of the upper pad 24 in the transverse direction Y is larger than the width (dimension in the transverse direction Y) of the first parallel line 21p1, similar to the upper pads 21d1 and 21d2 that form part of the first line 21.

[0048] 4, a first intermediate pad 24a and a second intermediate pad 24b are provided between the upper pad 24 and the second ground conductor 32 in the vertical direction Z. The upper pad 24, the first intermediate pad 24a, the second intermediate pad 24b, and the second ground conductor 32 overlap one another in a plan view. The upper pad 24, the first intermediate pad 24a, and the second intermediate pad 24b are aligned in this order from the upper side (+Z side) to the lower side (−Z side), and are spaced apart in the vertical direction Z.

[0049] The upper pad 24 and the first intermediate pad 24a are electrically and mechanically connected by a plurality of connecting conductors 50. The first intermediate pad 24a and the second intermediate pad 24b are electrically and mechanically connected by a plurality of connecting conductors 50. The second intermediate pad 24b and the second ground conductor 32 are electrically and mechanically connected by a plurality of connecting conductors 50. As a result, the upper pad 24 is constantly electrically connected to the second ground conductor 32.

[0050] In this specification, a "connection conductor 50" is a conductor extending in the vertical direction Z, and is a member that electrically and mechanically connects a member connected to the upper end of the connection conductor 50 with a member connected to the lower end of the connection conductor 50. The connection conductor 50 is, for example, a via that penetrates an insulating layer (not shown) in the vertical direction Z. Furthermore, the shapes and numbers of the connection conductors 50 shown in each figure are all examples, and can be changed as appropriate as long as they can connect a member connected to the upper end of the connection conductor 50 with a member connected to the lower end of the connection conductor 50.

[0051] However, the digital phase shift circuit B does not necessarily have to have the upper pad 24, the first intermediate pad 24a, the second intermediate pad 24b, and the connecting conductor 50 connecting them.

[0052] As shown in FIG. 1 , the upper pad 25 is a rectangular flat conductor similar to the upper pads 22d1 and 22d2 that form part of the second line 22. The long sides of the upper pad 25 extend in the transverse direction Y, and the short sides of the upper pad 25 extend in the longitudinal direction X. Of the short sides of the upper pad 25, the short side located on the +Y side is referred to as the first short side (one short side), and the short side located on the -Y side is referred to as the second short side (other short side). The second short side (-Y side) of the upper pad 25 is located at approximately the same position in the transverse direction Y as the second side edge (-Y side) of the second parallel line 22p2. The first short side (+Y side) of the upper pad 25 is located further back (+Y side) than the first side edge (+Y side) of the second parallel line 22p2. That is, the dimension of the upper pad 25 in the cross direction Y is larger than the width (dimension in the cross direction Y) of the second parallel line 22p2, similar to the upper pads 22d1 and 22d2 that form part of the second line 22.

[0053] 4, a first intermediate pad 25a and a second intermediate pad 25b are provided between the upper pad 25 and the second ground conductor 32 in the vertical direction Z. The upper pad 25, the first intermediate pad 25a, the second intermediate pad 25b, and the second ground conductor 32 overlap one another in a plan view. The upper pad 25, the first intermediate pad 25a, and the second intermediate pad 25b are aligned in this order from the upper side (+Z side) to the lower side (−Z side), and are spaced apart in the vertical direction Z.

[0054] The upper pad 25 and the first intermediate pad 25a are electrically and mechanically connected by a plurality of connecting conductors 50. The first intermediate pad 25a and the second intermediate pad 25b are electrically and mechanically connected by a plurality of connecting conductors 50. The second intermediate pad 25b and the second ground conductor 32 are electrically and mechanically connected by a plurality of connecting conductors 50. As a result, the upper pad 25 is constantly electrically connected to the second ground conductor 32.

[0055] The first ground conductor 31 is a plate-shaped conductor provided on the input end side (−X side) of the signal line 10. The first ground conductor 31 is electrically grounded. The first ground conductor 31 has a rectangular shape with long sides extending in the cross direction Y and short sides extending in the longitudinal direction X. The first ground conductor 31 overlaps with the front (−Y side) ends of the upper pads 21d1 and 22d1 and the first cross line 22c1 in the vertical direction Z. As shown in FIG. 2 , the first ground conductor 31 is located below (on the −Z side) the signal line 10, the first line 21 (upper pad 21d1), and the second line 22 (upper pad 22d1).

[0056] The second ground conductor 32 is a plate-shaped conductor provided on the output end side (+X side) of the signal line 10. The second ground conductor 32 is electrically grounded. Although not shown in detail, the second ground conductor 32 is located below (on the −Z side) the signal line 10, the first line 21, the second line 22, and the upper pads 24 and 25.

[0057] 2 , the first connection pad P1 includes the above-described upper pad 21d1, first intermediate pad 71a, second intermediate pad 71b, third intermediate pad 71c, and first ground conductor 31. The upper pad 21d1, first intermediate pad 71a, second intermediate pad 71b, third intermediate pad 71c, and first ground conductor 31 overlap one another in a plan view. The upper pad 21d1, first intermediate pad 71a, second intermediate pad 71b, third intermediate pad 71c, and first ground conductor 31 are aligned in this order from the upper side (+Z side) to the lower side (−Z side), and are spaced apart in the up-down direction Z.

[0058] 2 , the upper pad 21d1 and the first intermediate pad 71a are electrically and mechanically connected by a plurality of connecting conductors 50. The first intermediate pad 71a and the second intermediate pad 71b are electrically and mechanically connected by a plurality of connecting conductors 50. The second intermediate pad 71b and the third intermediate pad 71c are electrically and mechanically connected by a plurality of connecting conductors 50. The third intermediate pad 71c and the first ground conductor 31 are electrically and mechanically connected by a plurality of connecting conductors 50. As a result, the first connection pad P1 constantly electrically connects the first end (−X side) of the first parallel line 21p1 and the first ground conductor 31.

[0059] 2 , the second connection pad P2 includes an upper pad 22d1, a first intermediate pad 72a, a second intermediate pad 72b, a third intermediate pad 72c, and a first ground conductor 31. The upper pad 22d1, the first intermediate pad 72a, the second intermediate pad 72b, the third intermediate pad 72c, and the first ground conductor 31 overlap one another in a plan view. The upper pad 22d1, the first intermediate pad 72a, the second intermediate pad 72b, the third intermediate pad 72c, and the first ground conductor 31 are aligned in this order from the upper side (+Z side) to the lower side (−Z side), and are spaced apart in the up-down direction Z.

[0060] 2, the upper pad 22d1 and the first intermediate pad 72a are electrically and mechanically connected by a plurality of connecting conductors 50. The first intermediate pad 72a and the second intermediate pad 72b are electrically and mechanically connected by a plurality of connecting conductors 50. The second intermediate pad 72b and the third intermediate pad 72c are electrically and mechanically connected by a plurality of connecting conductors 50. The third intermediate pad 72c and the first ground conductor 31 are electrically and mechanically connected by a plurality of connecting conductors 50. As a result, the second connection pad P2 constantly electrically connects the first end (−X side) of the second parallel line 22p2 and the first ground conductor 31.

[0061] 2, the near side (-Y side) end of the first intersecting line 22c1 is connected to the second intermediate pad 72b included in the second connection pad P2. As a result, the second connection pad P2 constantly electrically connects the loop line RP and the first ground conductor 31. The near side (-Y side) end of the first intersecting line 22c1 may be connected to the third intermediate pad 72c included in the second connection pad P2.

[0062] 3, the third connection pad P3 includes the upper pad 21d2, the first intermediate pad 73a, the second intermediate pad 73b, the third intermediate pad 73c, and the lower pad 33a. The upper pad 21d2, the first intermediate pad 73a, the second intermediate pad 73b, the third intermediate pad 73c, and the lower pad 33a overlap one another in a plan view. The upper pad 21d2, the first intermediate pad 73a, the second intermediate pad 73b, the third intermediate pad 73c, and the lower pad 33a are aligned in this order from the upper side (+Z side) to the lower side (-Z side) and are spaced apart in the vertical direction Z.

[0063] 1 , the lower pad 33a is a rectangular flat conductor whose long sides extend in the transverse direction Y and whose short sides extend in the longitudinal direction X. The lower pad 33a is provided separately from the second ground conductor 32. The lower pad 33a and the second ground conductor 32 are electrically connected or disconnected depending on the state of a first electronic switch 41 (described later). Therefore, the lower pad 33a is electrically grounded or disconnected depending on the state of the first electronic switch 41.

[0064] 3 , the upper pad 21d2 and the first intermediate pad 73a are electrically and mechanically connected by a plurality of connecting conductors 50. The first intermediate pad 73a and the second intermediate pad 73b are electrically and mechanically connected by a plurality of connecting conductors 50. The second intermediate pad 73b and the third intermediate pad 73c are electrically and mechanically connected by a plurality of connecting conductors 50. The third intermediate pad 73c and the lower pad 33a are electrically and mechanically connected by a plurality of connecting conductors 50. As a result, the third connection pad P3 constantly electrically connects the second end (+X side) of the first parallel line 21p1 and the first electronic switch 41.

[0065] 3, the fourth connection pad P4 includes the upper pad 22d2, the first intermediate pad 74a, the second intermediate pad 74b, the third intermediate pad 74c, and the lower pad 33b. The upper pad 22d2, the first intermediate pad 74a, the second intermediate pad 74b, the third intermediate pad 74c, and the lower pad 33b overlap one another in a plan view. The upper pad 22d2, the first intermediate pad 74a, the second intermediate pad 74b, the third intermediate pad 74c, and the lower pad 33b are aligned in this order from the upper side (+Z side) to the lower side (-Z side) and are spaced apart in the vertical direction Z.

[0066] 1, the lower pad 33b is a rectangular flat conductor whose long sides extend in the transverse direction Y and whose short sides extend in the longitudinal direction X. The lower pad 33b is provided separately from the second ground conductor 32 and the lower pad 33a. The lower pad 33b and the second ground conductor 32 are electrically connected or disconnected depending on the state of a second electronic switch 42 (described below). Therefore, the lower pad 33b is electrically grounded or disconnected depending on the state of the second electronic switch 42.

[0067] 3 , the upper pad 22d2 and the first intermediate pad 74a are electrically and mechanically connected by a plurality of connecting conductors 50. The first intermediate pad 74a and the second intermediate pad 74b are electrically and mechanically connected by a plurality of connecting conductors 50. The second intermediate pad 74b and the third intermediate pad 74c are electrically and mechanically connected by a plurality of connecting conductors 50. The third intermediate pad 74c and the lower pad 33b are electrically and mechanically connected by a plurality of connecting conductors 50. As a result, the fourth connection pad P4 constantly electrically connects the second end (+X side) of the second parallel line 22p2 and the second electronic switch 42.

[0068] 2 , the capacitor 60 is a parallel plate whose upper electrode is connected to the signal line 10 and whose lower electrode is connected to the first ground conductor 31 via the third electronic switch 43. The capacitor 60 has a capacitance Ca corresponding to the opposing area of ​​the parallel plates. In other words, the capacitance Ca is a circuit constant provided between the signal line 10 and the first ground conductor 31. However, the capacitor 60 may also be an interdigital capacitor.

[0069] 1, the first electronic switch 41 is a transistor that can open and close between the lower pad 33a of the third connection pad P3 and the second ground conductor 32. As shown in FIG. 1, the first electronic switch 41 in this embodiment is, for example, a MOS type FET (field effect transistor), and has a drain terminal connected to the lower pad 33a of the third connection pad P3, a source terminal connected to the second ground conductor 32, and a gate terminal connected to the switch control unit 80.

[0070] The first electronic switch 41 switches the conduction state between the drain terminal and the source terminal between an open state and a closed state based on a gate signal input to the gate terminal from the switch control unit 80. That is, the first electronic switch 41, by the switch control unit 80, brings the second end (+X side) of the first parallel line 21p1 and the second ground conductor 32 into a conductive state or a cut-off state.

[0071] 1, the second electronic switch 42 is a transistor that opens and closes the lower pad 33b of the fourth connection pad P4 and the second ground conductor 32. As shown in FIG. 1, the second electronic switch 42 in this embodiment is, for example, a MOS type FET, and has a drain terminal connected to the lower pad 33b of the fourth connection pad P4, a source terminal connected to the second ground conductor 32, and a gate terminal connected to the switch control unit 80.

[0072] The second electronic switch 42 switches the conduction state between the drain terminal and the source terminal between an open state and a closed state based on a gate signal input to the gate terminal from the switch control unit 80. That is, the second electronic switch 42 switches the conduction state between the second end (+X side) of the second parallel line 22p2 and the second ground conductor 32 between an open state and a closed state by the switch control unit 80.

[0073] 2, the third electronic switch 43 is a transistor that opens and closes the connection between the lower electrode of the capacitor 60 and the first ground conductor 31. The third electronic switch 43 is, for example, a MOS type FET, and has a drain terminal connected to the lower electrode of the capacitor 60, a source terminal connected to the first ground conductor 31, and a gate terminal connected to the switch control unit 80.

[0074] 2, the third electronic switch 43 is disposed at a position away from the signal line 10 on the rear side (+Y side). In addition, the first end (+Y side) of the first ground conductor 31 extends away from the signal line 10 in the cross direction Y and is connected to the third electronic switch 43. The reason for this arrangement is that there are design rule restrictions on the connection of the lower electrode of the capacitor 60 in certain semiconductor manufacturing processes.

[0075] Specifically, this constraint requires that the lower electrode of the capacitor 60 must first be connected to an upper wiring layer (e.g., the layer on which the signal line 10 is formed) via a connecting wire and a via, and then be connected from that wiring layer to a lower wiring layer via a via. Note that FIG. 2 shows a simplified connection path between the lower electrode of the capacitor 60 and the third electronic switch 43. Due to this constraint, the third electronic switch 43 cannot be placed near the position where the capacitor 60 is formed (e.g., the input end (−X side) of the signal line 10 shown in FIG. 1 ), but must be placed at a location farther away from the signal line 10 (+Y side). The first ground conductor 31 extends away from the signal line 10 in the cross direction Y in order to be connected to the source terminal of the third electronic switch 43 placed in this position.

[0076] The third electronic switch 43 switches the conduction state between the drain terminal and the source terminal between an open state and a closed state based on a gate signal input to the gate terminal from the switch control unit 80. In other words, the third electronic switch 43 brings the lower electrode of the capacitor 60 and the first ground conductor 31 into a conductive state or a cut-off state by the switch control unit 80.

[0077] 2 , the fourth electronic switch 44 is a transistor that can open and close between the input end (−X side) of the signal line 10 and the first ground conductor 31. Like the first electronic switch 41, the second electronic switch 42, and the third electronic switch 43 described above, the fourth electronic switch 44 is a MOS-type FET, with a drain terminal connected to the input end (−X side) of the signal line 10, a source terminal connected to the first ground conductor 31, and a gate terminal connected to the switch control unit 80. Note that the fourth electronic switch 44 may be provided between the output end (+X side) of the signal line 10 and the second ground conductor 32, instead of between the input end (−X side) of the signal line 10 and the first ground conductor 31.

[0078] The fourth electronic switch 44 switches the conduction state between the drain terminal and the source terminal between an open state and a closed state based on a gate signal input to the gate terminal from the switch control unit 80. That is, the fourth electronic switch 44 brings the input end side (−X side) of the signal line 10 and the first ground conductor 31 into a conductive state or a cut-off state by the switch control unit 80.

[0079] The switch control unit 80 is a control circuit that controls the above-mentioned first electronic switch 41, second electronic switch 42, third electronic switch 43, and fourth electronic switch 44. The switch control unit 80 has four output ports, and outputs gate signals from each output port to the gate terminals of the first electronic switch 41, second electronic switch 42, third electronic switch 43, and fourth electronic switch 44 individually. That is, the switch control unit 80 opens or closes the first electronic switch 41, second electronic switch 42, third electronic switch 43, and fourth electronic switch 44 according to the gate signals.

[0080] Next, the operation of the digital phase shift circuit B configured as above will be described.

[0081] In the digital phase shift circuit B of this embodiment, the operation mode is switched depending on the conduction states of the first to third electronic switches 41 to 43. That is, the operation modes of the digital phase shift circuit B include a low delay mode in which the first electronic switch 41 and the second electronic switch 42 are set to a closed state and the third electronic switch 43 is set to an open state by the switch control unit 80, and a high delay mode in which the first electronic switch 41 and the second electronic switch 42 are set to an open state and the third electronic switch 43 is set to a closed state by the switch control unit 80.

[0082] In the low delay mode, the switch control unit 80 sets the first electronic switch 41 and the second electronic switch 42 to a closed state and sets the third electronic switch 43 to an open state. That is, in the low delay mode, the first propagation delay time T Ｌ The phase at the output end (right end) is the second phase θ ＨA first phase θ smaller than Ｌ The low latency mode will be explained in more detail below.

[0083] When the first electronic switch 41 is set to a closed state, the second end (+X side) of the first parallel line 21p1 is connected to the second ground conductor 32 via the third connection pad P3 (see FIG. 1). Meanwhile, the first end (-X side) of the first parallel line 21p1 is constantly connected to the first ground conductor 31 via the first connection pad P1 (see FIGS. 1 and 2). Therefore, when the second end (+X side) of the first parallel line 21p1 is connected to the second ground conductor 32 via the first electronic switch 41, a first current path is formed through which a current can flow between the first end (-X side) and the second end (+X side).

[0084] Furthermore, by setting the second electronic switch 42 to a closed state, the second end (+X side) of the second parallel line 22p2 is connected to the second ground conductor 32 via the fourth connection pad P4 (see FIG. 1). Meanwhile, the first end (-X side) of the second parallel line 22p2 is constantly connected to the first ground conductor 31 via the second connection pad P2 (see FIGS. 1 and 2). Therefore, by connecting the second end (+X side) of the second parallel line 22p2 to the second ground conductor 32 via the second electronic switch 42, a second current path is formed through which a current can flow between the first end (-X side) and the second end (+X side).

[0085] When both ends of the first parallel line 21p1 and the second parallel line 22p2 are connected, if a signal current flows from the input end to the output end of the signal line 10, a return current is generated in the first parallel line 21p1 and the second parallel line 22p2 due to the propagation of the signal current. The return current flows through the first parallel line 21p1 and the second parallel line 22p2 from the second end (+X side) to the first end (−X side).

[0086] That is, a first return current flows in the first parallel line 21p1 forming the first current path in the opposite direction to the direction of the signal current due to the flow of the signal current in the signal line 10. Furthermore, a second return current flows in the second parallel line 22p2 forming the second current path in the opposite direction to the direction of the signal current, i.e., in the same direction as the first return current, due to the flow of the signal current in the signal line 10.

[0087] Here, the first return current flowing through the first parallel line 21p1 and the second return current flowing through the second parallel line 22p2 are both opposite to the direction of the signal current. Therefore, the first return current and the second return current act to reduce the overall inductance of the digital phase shift circuit B due to the electromagnetic coupling (mutual induction) between the signal line 10 and the first parallel line 21p1 and the electromagnetic coupling (mutual induction) between the signal line 10 and the second parallel line 22p2. When the inductance of the signal line 10 is reduced to Ls ｌｏｗ , the inductance of the return path (the first parallel line 21p1 and the second parallel line 22p2) is Lg ｌｏｗ , the mutual inductance between the signal line 10 and the return path is M ｌｏｗ The total inductance L of the digital phase shift circuit B in the low delay mode is ｌｏｗ is Ls ｌｏｗ + Lg ｌｏｗ -M ｌｏｗ This becomes:

[0088] As described above, the signal line 10 has a capacitance C1 as a parasitic capacitance. In the low delay mode, the third electronic switch 43 is set to an open state, and therefore the capacitor 60 is not connected between the signal line 10 and the first ground conductor 31. In other words, the capacitance Ca of the capacitor 60 does not affect the high-frequency signal propagating through the signal line 10. Therefore, the high-frequency signal propagating through the signal line 10 has a capacitance C1 (L ｌｏｗ ×C1) １／２ The first propagation delay time T Ｌ is effective.

[0089] The high-frequency signal at the output end of the signal line 10 has a first propagation delay time T Ｌ, the phase of the high frequency signal at the input end of the signal line 10 becomes a first phase θ Ｌ That is, in the low delay mode, the total inductance of the digital phase shift circuit B is delayed by the inductance L ｌｏｗ This reduces the propagation delay time.

[0090] On the other hand, in the high delay mode, the switch control unit 80 sets the first electronic switch 41 and the second electronic switch 42 to an open state, and sets the third electronic switch 43 to a closed state. The fourth electronic switch 44 is set to a closed state. That is, in the high delay mode, the second propagation delay time T Ｈ The phase at the output terminal (right terminal) is the first phase θ Ｌ A second phase θ greater than Ｈ The high latency mode will be explained in more detail below.

[0091] As described above, in the high delay mode, the first electronic switch 41 and the second electronic switch 42 are set to the open state. Therefore, the first conductive path described above is not formed in the first parallel line 21p1, and the second conductive path described above is not formed in the second parallel line 22p2. Therefore, the first return current flowing in the first parallel line 21p1 is extremely small, and the second return current flowing in the second parallel line 22p2 is extremely small.

[0092] In contrast, the near side (-Y side) end of the first intersecting line 22c1, which is part of the loop line RP, is constantly connected to the first ground conductor 31 via the second connection pad P2 (see FIG. 2 ). Furthermore, the first end (-Y side) of the second intersecting line 22c2, which is part of the loop line RP, is constantly connected to the second ground conductor 32, as described above. Therefore, a third current path is formed in advance in the loop line RP, through which a current can flow between the first end (-Y side) of the second intersecting line 22c2 and the near side (-Y side) end of the first intersecting line 22c1. Therefore, in the high delay mode, a third return current flows from the first end (-Y side) of the second intersecting line 22c2 to the near side (-Y side) end of the first intersecting line 22c1 via the bent line 22b and the third parallel line 22p3, due to the signal current in the signal line 10.

[0093] Here, the third return current flows in the third parallel line 22p3 parallel to the signal line 10 and in the partial line 22b2 of the bent line 22b, in a direction opposite to the direction of the signal current flowing in the signal line 10. Furthermore, the partial line 22b1 of the bent line 22b, the third parallel line 22p3, and the first intersecting line 22c1 form a loop line RP that is convex on the opposite side (+Y side) from the signal line 10. Therefore, the inductance of the return path (path through which the third return current flows) can be increased compared to a conventional configuration in which the loop line RP is not formed. Moreover, in this embodiment, the thickness of the loop line RP (the thickness of the first intersecting line 22c1, the third parallel line 22p3, the bent line 22b, and the second intersecting line 22c2) is smaller than the thickness of the signal line 10, the first line 21, the second parallel line 22p2, and the upper pads 22d1 and 22d2.

[0094] This allows the overall inductance of the digital phase shift circuit B to be significantly increased, and a desired phase shift amount can be ensured even at low frequencies where the phase shift amount is small. ｈｉｇｈ , the inductance of the return path (the second intersecting line 22c2, the bent line 22b, the third parallel line 22p3, and the first intersecting line 22c1) is Lg ｈｉｇｈ , the mutual inductance between the signal line 10 and the return path is M ｈｉｇｈIn addition, Ls ｈｉｇｈ = Ls ｌｏｗ The total inductance L of the digital phase shift circuit B in the high delay mode ｈｉｇｈ is Ls ｈｉｇｈ + Lg ｈｉｇｈ -M ｈｉｇｈ Here, it is clear that Lg ｌｏｗ <Lg ｈｉｇｈ and M ｌｏｗ >M ｈｉｇｈ Since this holds, L ｈｉｇｈ >L ｌｏｗ holds true.

[0095] The principle by which the third return current acts to increase the inductance of the return path can be explained as follows. Specifically, the magnetic field generated when the third return current flows through the partial line 22b1 of the bent line 22b, the magnetic field generated when the third return current flows through the third parallel line 22p3, and the magnetic field generated when the third return current flows through the first intersecting line 22c1 all have the same direction (+Z direction) within the loop line. Therefore, these magnetic fields reinforce each other. Therefore, compared to a conventional configuration in which the line through which the third return current flows does not form a loop line, the magnetic field generated by the third return current can be made larger, thereby increasing the inductance of the return path. Furthermore, the inductance of the return path can be significantly changed by adjusting the height of the loop (i.e., the position of the third parallel line 22p3 in the intersecting direction Y, and the first intersecting line 22c1 and the partial line 22b1 of the bent line 22b).

[0096] On the other hand, the signal line 10 has a capacitance C1 as a parasitic capacitance. In addition, in the high delay mode, the third electronic switch 43 is set to a closed state, and therefore the capacitor 60 is connected between the signal line 10 and the first ground conductor 31. That is, the signal line 10 has a capacitance Cb which is the sum of the capacitance Ca of the capacitor 60 and the capacitance C1 (parasitic capacitance). Therefore, the high-frequency signal propagating through the signal line 10 experiences a second propagation delay time T Ｈ is effective.

[0097] The high-frequency signal at the output end of the signal line 10 has a second propagation delay time T Ｈ , the phase of the high frequency signal at the input end of the signal line 10 becomes a second phase θ Ｈ That is, in the high delay mode, the inductance of the transmission system is increased due to the third return current, thereby increasing the propagation delay time.

[0098] In the high delay mode, the fourth electronic switch 44 may be set to a closed state to intentionally increase the loss in the signal line 10. This loss is intended to make the loss of the high frequency signal in the high delay mode the same as the loss of the high frequency signal in the low delay mode.

[0099] <Output Transmission Line> Fig. 5 is a cross-sectional view taken along line VV shown in Fig. 1. As shown in Fig. 1 and Fig. 5, the output transmission line 90 according to this embodiment constitutes a so-called microstrip line, and includes a signal line (output-side signal line) 91 and a ground layer 92. The ground layer 92 functions as a ground conductor (output-side ground conductor) for the output transmission line 90.

[0100] 1 , the signal line 91 is a linear strip-shaped conductor extending in the longitudinal direction X. That is, the signal line 91 is a long, plate-shaped conductor having a constant width, a constant thickness, and a predetermined length. The signal line 91 is electrically connected to the signal line 10 of the digital phase shift circuit B via a signal line 101 (details of which will be described later) of the output matching circuit 100. The signal line 91 is formed on the same layer as the signal line 10.

[0101] 1, the ground layer 92 is a plate-shaped conductor extending in the longitudinal direction X and the transverse direction Y. The ground layer 92 is electrically connected to the second ground conductor 32 of the digital phase shift circuit B via a return line 102 (details of which will be described later) of the output matching circuit 100, etc. The ground layer 92 is disposed below the signal line 91 at a predetermined distance, as shown in FIG.

[0102] 1, the output matching circuit 100 according to this embodiment includes a signal line 101 and a return line 102. The return line 102 according to this embodiment includes a shift line 102s, a first intersecting line 102c1, a parallel line 102p, and a second intersecting line 102c2.

[0103] The signal line 101 according to this embodiment is formed on the same layer as the signal line 10 of the digital phase shift circuit B and the signal line 91 of the output transmission line 90 .

[0104] The return line 102 according to this embodiment is formed on a layer different from the layer on which the signal line 101 is formed. More specifically, the return line 102 according to this embodiment is formed on a layer on which the intermediate pads 24b and 25b (see FIG. 4 ) of the digital phase shift circuit B and the ground layer 92 (see FIG. 5 ) of the output transmission line 90 are formed. In other words, the return line 102 is formed on a layer (inner layer) below the layer on which the signal line 101 is formed. As a result, the thickness (cross-sectional area) of the return line 102 is smaller than the thickness (cross-sectional area) of the signal line 101.

[0105] The signal line 101 is a linear strip-shaped conductor extending in the longitudinal direction X. That is, the signal line 101 is a long, plate-shaped conductor having a constant width, a constant thickness, and a predetermined length. The signal line 101 is connected to the signal line 10 of the digital phase shift circuit B and the signal line 91 of the output transmission line 90. In this embodiment, the width (cross-sectional area) of the signal line 101 is smaller than both the width (cross-sectional area) of the signal line 10 of the digital phase shift circuit B and the width (cross-sectional area) of the signal line 91 of the output transmission line 90.

[0106] The shift line 102s according to this embodiment extends from the second intermediate pad 25b (see also FIG. 4 ) to the right (+X side) in the longitudinal direction X, away from the digital phase-shift circuit B. The right edge (+X side) of the shift line 102s is located to the right (+X side) of the right side edge (+X side) of the second ground conductor 32.

[0107] The shift line 102s is electrically connected to the second ground conductor 32 via the second intermediate pad 25b and the connecting conductor 50 (see FIG. 4). Therefore, the return line 102 including the shift line 102s is electrically connected to the second ground conductor 32 via the second intermediate pad 25b and the connecting conductor 50. Of the ends of the shift line 102s, the end located on the +X side is referred to as a first end (one end), and the end located on the −X side is referred to as a second end (the other end). The second end of the shift line 102s is also the second end of the return line 102.

[0108] As shown in FIG. 1 , the first intersecting line 102c1 is a linear strip-shaped conductor connected to the first end (+X side) of the shift line 102s. The first intersecting line 102c1 is a long, plate-shaped conductor having a constant width, a constant thickness, and a predetermined length. The first intersecting line 102c1 extends from near the first end (-X side) of the signal line 101 in the crossing direction Y, away from the signal line 101. Specifically, the first intersecting line 102c1 according to this embodiment extends from the first end (+X side) of the shift line 102s in the crossing direction Y, away from the signal line 101. In other words, the first intersecting line 102c1 according to this embodiment extends from the first end (+X side) of the shift line 102s toward the rear (+Y side). Of the ends of the first intersecting line 102c1, the end located on the +Y side is referred to as a first end (one end), and the end located on the -Y side is referred to as a second end (the other end).

[0109] The first intersecting line 102c1 of the output matching circuit 100 and the second intersecting line 22c2 of the digital phase shift circuit B do not overlap in a plan view. That is, in a plan view, the first intersecting line 102c1 of the output matching circuit 100 and the second intersecting line 22c2 of the digital phase shift circuit B are spaced apart in the longitudinal direction X.

[0110] The parallel line 102p is a linear strip-shaped conductor connected to the first end (+Y side) of the first intersecting line 102c1. The parallel line 102p is a long, plate-shaped conductor having a constant width, a constant thickness, and a predetermined length. The parallel line 102p extends from the first end (+Y side) of the first intersecting line 102c1 in parallel to the signal line 101 (longitudinal direction X). In other words, the parallel line 102p according to this embodiment extends from the first end (+Y side) of the first intersecting line 102c1 toward the right side (+X side). Of the ends of the parallel line 102p, the end located on the +X side is referred to as the first end (one end), and the end located on the -X side is referred to as the second end (the other end).

[0111] The second intersecting line 102c2 is a linear strip-shaped conductor connected to the first end (+X side) of the parallel line 102p. The second intersecting line 102c2 is a long, plate-shaped conductor having a constant width, a constant thickness, and a predetermined length. The second intersecting line 102c2 extends from the first end (+X side) of the parallel line 102p in the intersecting direction Y toward the signal line 101. That is, the second intersecting line 102c2 according to this embodiment extends from the first end (+X end) of the parallel line 102p toward the near side (-Y side). Of the ends of the second intersecting line 102c2, the end located on the -Y side is referred to as the first end (one end), and the end located on the +Y side is referred to as the second end (the other end). The first end of the second intersecting line 102c2 is also the first end of the return line 102.

[0112] 1 and 5, the front edge (-Y side) of the second crossing line 102c2 is connected to the rear side edge (+Y side) of the ground layer 92 of the output transmission line 90. Therefore, the return line 102 including the second crossing line 102c2 is electrically connected to the ground layer 92 (output-side ground conductor) of the output transmission line 90.

[0113] The return line 102 described above has a loop shape that is convex in the direction away from the signal line 101 in the transverse direction Y. That is, the return line 102 according to this embodiment constitutes a U-shaped loop line that is convex toward the rear (+Y side). Because the return line 102 has such a loop shape, the return line 102 is longer than the signal line 101. Furthermore, the return line 102 according to this embodiment has a smaller width (cross-sectional area) than the loop line RP of the digital phase shift circuit B. The return line 102 extends so as to at least partially overlap with the signal line 101 as viewed from the transverse direction Y. For example, the parallel line 102p according to this embodiment extends in the longitudinal direction X so as to overlap with the signal line 101 as viewed from the transverse direction Y.

[0114] <<Function>> Next, the function of the output matching circuit 100 configured as above will be described.

[0115] As described above, the digital phase shift circuit of Patent Document 1 includes a signal line, a first line including a first parallel line, a second line including a second parallel line, a first ground conductor, a second ground conductor, a first electronic switch, and a second electronic switch. The second line includes a loop line that is convex in a direction away from the signal line. The digital phase shift circuit of Patent Document 1 has the advantage of being compact and capable of increasing the difference between the phase in the low delay mode and the phase in the high delay mode by configuring the return current to flow through the loop line in the high delay mode. This digital phase shift circuit may be used by being connected to an output transmission line formed by multiple conductors (in this embodiment, two conductors: a signal line 91 and a ground layer 92).

[0116] However, when the above-mentioned digital phase shift circuit is miniaturized, the spacing between conductors becomes smaller, which increases parasitic capacitance, making it difficult to match the input / output impedance to a real load. A commonly known method for matching the input / output impedance to a real load is to connect an inductor in series with the output unit. However, the above-mentioned digital phase shift circuit (output unit) is composed of multiple conductors. This makes it difficult to connect an inductor, which is a lumped element, in series between the digital phase shift circuit composed of multiple conductors and the output transmission line also composed of multiple conductors.

[0117] To solve this problem, the output matching circuit 100 according to this embodiment is configured with multiple conductor lines. Specifically, the output matching circuit 100 includes a signal line 101 connected to the signal line 10 of the digital phase shift circuit B and the signal line 91 of the output transmission line 90, and a return line 102 connected to the second ground conductor 32 of the digital phase shift circuit B and the ground layer 92 (output-side ground conductor) of the output transmission line 90. This allows the output matching circuit 100 as an inductance component to be easily connected in series between the digital phase shift circuit B, which is configured with multiple conductors, and the output transmission line 90, which is also configured with multiple conductors. This allows the input / output impedance to be matched to a real load even when the digital phase shift circuit B and the output transmission line 90 are configured with multiple conductors.

[0118] Here, the inductance component of the output matching circuit 100 as a whole is determined based on the sum of the inductance component of the signal line 101 and the inductance component of the return line 102. In this embodiment, since the return line 102 has a loop shape, the inductance component of the return line 102 can be increased based on the same principle as the loop line RP. This increases the inductance component of the output matching circuit 100 as a whole. Furthermore, by adjusting the loop design of the return line 102, the intended inductance component can be obtained. For example, the intended inductance component can be obtained by adjusting the height of the loop of the return line 102 (i.e., the position in the cross direction Y of the parallel lines 102p).

[0119] Furthermore, in this embodiment, the return line 102 is the only GND path for the signal line 101. This reduces the capacitance component compared to, for example, a case where a separate ground layer or the like is provided below the signal line 101, and also makes it possible to achieve a high inductance component in the signal line 101.

[0120] <Summary> As described above, the output matching circuit 100 according to this embodiment electrically connects the digital phase shift circuit B and the output transmission line 90, and the digital phase shift circuit B includes the signal line (circuit-side signal line) 10, the first line 21 including the first parallel line 21p1 extending parallel to the signal line 10, the second parallel line 22p2 extending parallel to the signal line 10, and the second line 22 including the loop line RP extending from a first end of the second parallel line 22p2 to near the second end of the second parallel line 22p2 and having a convex shape in a direction away from the signal line 10 in the cross direction Y, the first ground conductor 31 electrically connected to the first end of the first parallel line 21p1 and the first end of the second parallel line 22p2, and the second ground conductor 31 connected to the first end of the second parallel line 22p2. an output matching circuit (100) having a ground conductor (32), a first electronic switch (41) provided between the second end of the first parallel line (21p1) and the second ground conductor (32), and a second electronic switch (42) provided between the second end of the second parallel line (22p2) and the second ground conductor (32); a signal line (10) is located between the first parallel line (21p1) and the second parallel line (22p2) in the digital phase shift circuit (B); an output transmission line (90) having a signal line (output side signal line) 91 and an output side ground conductor (ground layer 92); and a signal line (101) connected to the signal line (10) and the signal line (91), and a return line (102) electrically connected to the second ground conductor (32) and the output side ground conductor (ground layer 92), the return line (102) being longer than the signal line (101).

[0121] With this configuration, the output matching circuit 100 is configured with a plurality of conductor lines. As a result, even if the digital phase shift circuit B and the output transmission line 90 are configured with a plurality of conductors, the output matching circuit 100 can be easily connected in series between them as an inductance component, thereby enabling matching of the input and output impedances to a real load.

[0122] Furthermore, the cross-sectional area of ​​the return line 102 is smaller than the cross-sectional area of ​​the loop line RP. With this configuration, the inductance component of the return line 102 can be increased.

[0123] The return line 102 has a loop shape that is convex in the direction away from the signal line 101 in the cross direction Y. This configuration can increase the inductance component of the return line 102. As a result, the inductance component of the output matching circuit 100 as a whole can be increased.

[0124] In addition, the return line 102 includes, in a plan view, a first intersecting line 102c1 extending from near a first end of the signal line 101 so as to move away from the signal line 101 in the crossing direction Y, a parallel line 102p extending from the first end of the first intersecting line 102c1 in parallel to the signal line 101, and a second intersecting line 102c2 extending from the first end of the parallel line 102p so as to move closer to the signal line 101 in the crossing direction Y. This configuration makes it easy to realize the return line 102 that is convex in the direction moving away from the signal line 101 in the crossing direction Y.

[0125] Furthermore, the cross-sectional area of ​​at least a part of the return line 102 is smaller than the cross-sectional area of ​​the signal line 101. With this configuration, the inductance component of the return line 102 can be increased.

[0126] Second Embodiment Overview Next, a second embodiment will be described, which has the same basic configuration as the first embodiment. Therefore, the same components are denoted by the same reference numerals, and a description thereof will be omitted. Only the differences will be described. In particular, the configuration of the digital phase shift circuit B and the configuration of the output transmission line 90 are the same as those of the first embodiment, and therefore a description thereof will be omitted.

[0127] 6, the output matching circuit 100A according to this embodiment differs from the output matching circuit 100 according to the first embodiment in the shape of the return line 102A. The return line 102A according to this embodiment includes a shift line 102s, a first intersecting line 102c1, a parallel line 102p, a bent line 102b, and a second intersecting line 102c2. Of these, the shapes of the shift line 102s and the first intersecting line 102c1 are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0128] The parallel line 102p according to this embodiment extends from the first end (+Y side) of the first intersecting line 102c1 toward the right side (+X side), similarly to the first embodiment. However, the length of the parallel line 102p according to this embodiment is shorter than the length of the parallel line 102p according to the first embodiment. The length of the parallel line 102p is shorter than the length of the signal line 101.

[0129] The bent line 102b is a strip-shaped conductor connected to the first end (+X side) of the parallel line 102p and having a bend CR. The bent line 102b is composed of a first sub-line 102b1 and a second sub-line 102b2. The first sub-line 102b1 extends from the first end (+X side) of the parallel line 102p toward the signal line 101 in the cross direction Y. That is, the sub-line 102b1 according to this embodiment extends from the first end (+X side) of the parallel line 102p toward the near side (-Y side). Of the ends of the first sub-line 102b1, the end located on the -Y side is referred to as the first end (one end), and the end located on the +Y side is referred to as the second end (the other end). The second partial line 102b2 extends parallel to the signal line 101 (in the longitudinal direction X) from the first end (-Y side) of the first partial line 102b1. The end of the second partial line 102b2 located on the +X side is referred to as the first end (one end), and the end located on the -X side is referred to as the second end (the other end). The partial line 102b2 according to this embodiment extends from the first end (-Y side) of the first partial line 102b1 to the right (+X side). The partial lines 102b1 and 102b2 constituting the bent line 102b are each a long, plate-shaped conductor having a constant width, a constant thickness, and a predetermined length. The length of the first partial line 102b1 is shorter than the length of the first cross line 102c1. The bent line 102b may have multiple bends CR. In this embodiment, the first end of the second line portion 102b2 is the first end (one end) of the curved line 102b, and the second end of the first line portion 102b1 is the second end (the other end) of the curved line 102b.

[0130] The second intersecting line 102c2 according to this embodiment extends from a first end (+X side) of the second partial line 102b2 constituting the bent line 102b toward the signal line 101 in the intersecting direction Y. That is, the second intersecting line 102c2 according to this embodiment extends from the first end (+X end) of the second partial line 102b2 constituting the bent line 102b toward the near side (-Y side). As in the first embodiment, the near end edge (-Y side) of the second intersecting line 102c2 is connected to the far side edge (+Y side) of the ground layer 92 of the output transmission line 90.

[0131] The return line 102A according to the present embodiment described above forms a loop line that is convex toward the rear side (+Y side), similar to the first embodiment. Therefore, the same effects as those of the first embodiment can be obtained.

[0132] Incidentally, the output matching circuit 100 in the first embodiment and the output matching circuit 100A in the second embodiment each have the properties of a transmission line consisting of two lines. In the output matching circuit 100 in the first embodiment (see FIG. 1), the characteristic impedance of the transmission line can be controlled by changing the distance in the crossing direction Y between the lines 101 and 102p. More specifically, the inductance can be adjusted by changing the lengths of the crossing lines 102c1 and 102c2, thereby significantly changing the characteristic impedance of the transmission line. On the other hand, in the output matching circuit 100A in the second embodiment (see FIG. 6), the characteristic impedance of the transmission line can be controlled by changing two distances: the distance in the crossing direction Y between the lines 101 and 102p and the distance in the crossing direction Y between the lines 101 and 102b2.

[0133] In the second embodiment, the lengths (dimensions in the longitudinal direction X) of the section (first section) where the lines 101 and 102p run parallel to each other and the section (second section) where the lines 101 and 102b2 run parallel to each other are shorter than the lengths of the sections where the lines 101 and 102p run parallel to each other in the first embodiment (see FIGS. 1 and 6 ). Therefore, in the second embodiment, compared to the first embodiment, it is easier to make the lengths of the sections (first section, second section) that function as transmission lines sufficiently short relative to the wavelength of the high-frequency signal. Therefore, in the second embodiment, a lumped-constant effect (e.g., inductance) can be expected to be greater than in the first embodiment.

[0134] In the output matching circuit 100 according to the first embodiment, the same effect as described above can be expected by sufficiently shortening the lengths of the lines 101 and 102p. However, there are cases where it is difficult to sufficiently shorten the lengths of the lines 101 and 102p in the first embodiment due to, for example, constraints on the layout of peripheral circuits. In such cases, the configuration of the second embodiment, i.e., the configuration in which the return line 102A includes the bent line 102b, is preferable.

[0135] Summary As described above, the return line 102A according to the present embodiment includes, in a plan view, the first intersecting line 102c1 extending from near a first end of the signal line 101 so as to move away from the signal line 101 in the crossing direction Y, the parallel line 102p extending from the first end of the first intersecting line 102c1 in parallel to the signal line 101 and having a length shorter than that of the signal line 101, and the bent line 102b connected to the first end of the parallel line 102p, extending in the crossing direction Y for a length shorter than that of the first intersecting line 102c1 so as to move closer to the signal line 101, and then extending in parallel to the signal line 101 so as to move away from the first intersecting line 102c1. This configuration also makes it possible to realize the return line 102A that is convex in the direction away from the signal line 101 in the crossing direction Y.

[0136] <Third Embodiment> <Overview> Next, a third embodiment will be described, which has the same basic configuration as the second embodiment. Therefore, the same components are denoted by the same reference numerals and their description will be omitted, and only the differences will be described. In particular, the configuration of the digital phase shift circuit B and the configuration of the output transmission line 90 are the same as those of the second embodiment, and therefore their description will be omitted.

[0137] 7, the output matching circuit 100B according to this embodiment is different from the output matching circuit 100A according to the second embodiment in the shape of the return line 102B. The return line 102B according to this embodiment includes a shift line 102s, a first intersecting line 102c1, a parallel line 102p, a bent line 102b, and a second intersecting line 102c2. Of these, the shape of the shift line 102s is the same as that of the second embodiment, so a description thereof will be omitted.

[0138] The first intersecting line 102c1 according to this embodiment is a strip-shaped conductor connected to a first end (+X side) of the shift line 102s, as in the second embodiment. Unlike the second embodiment, the first intersecting line 102c1 according to this embodiment has a bent portion CR1 formed therein, and the side closer to the signal line 101 (e.g., closer to the signal line 101 than the midpoint of the first intersecting line 102c1 in the Y direction) has a crank shape. In a plan view, the first intersecting line 102c1 extends from the first end (+X side) of the shift line 102s, away from the signal line 101 in the crossing direction Y, bends to the right (+X side) at the bent portion CR1, and then extends again away from the signal line 101 in the crossing direction Y. As in the second embodiment, the parallel line 102p is connected to the first end (+Y side) of the first intersecting line 102c1.

[0139] The parallel line 102p according to this embodiment extends from the first end (+Y side) of the first intersecting line 102c1 toward the right side (+X side), similar to the second embodiment, except that the length of the parallel line 102p according to this embodiment is shorter than the length of the parallel line 102p according to the second embodiment.

[0140] Similar to the second embodiment, the curved line 102b according to this embodiment includes a first line segment 102b1 extending from a first end (+X side) of the parallel line 102p toward the near side (-Y side), and a second line segment 102b2 extending from the first end (-Y side) of the first line segment 102b1 toward the right side (+X side). However, the length of the second line segment 102b2 according to this embodiment is shorter than the length of the second line segment 102b2 according to the second embodiment.

[0141] Similar to the second embodiment, the second intersecting line 102c2 according to this embodiment is a strip-shaped conductor connected to a first end (+X side) of the second partial line 102b2 constituting the bent line 102b. Unlike the second embodiment, the second intersecting line 102c2 according to this embodiment has a bend CR2 formed therein, and the side closer to the signal line 101 (e.g., closer to the signal line 101 than the midpoint of the second intersecting line 102c2 in the Y direction) has a crank shape. In a plan view, the second intersecting line 102c2 extends from the first end (+X side) of the second partial line 102b2 constituting the bent line 102b toward the signal line 101 in the crossing direction Y, bends to the right (+X side) at the bend CR2, and then extends again toward the signal line 101 in the crossing direction Y. The front edge (-Y side) of the second intersecting line 102c2 is connected to the rear side edge (+Y side) of the ground layer 92 of the output transmission line 90, as in the second embodiment.

[0142] <<Function>> The return line 102B according to the present embodiment described above forms a loop line that is convex toward the rear side (+Y side), similar to the first and second embodiments, and therefore can achieve the same effects as the first and second embodiments.

[0143] The output matching circuit 100B according to the third embodiment also has properties as a transmission line consisting of two lines, similar to the output matching circuits 100 and 100A according to the first and second embodiments. In the output matching circuit 100B according to the third embodiment (see FIG. 7 ), the characteristic impedance of the transmission line can be controlled by changing three distances: the distance in the crossing direction Y between the lines 101 and 102p, the distance in the crossing direction Y between the lines 101 and 102b2, and the distance in the crossing direction Y between the portion of the second crossing line 102c2 extending in the longitudinal direction X and the signal line 101.

[0144] In the third embodiment, the length (dimension in the longitudinal direction X) of the section (first section) where the lines 101 and 102p run parallel to each other and the section (second section) where the lines 101 and 102b2 run parallel to each other is shorter than the lengths of the sections in the first and second embodiments (see FIGS. 1, 6, and 7). Therefore, in the third embodiment, a lumped-parameter-like effect (e.g., inductance) can be further expected compared to the first and second embodiments.

[0145] <Fourth Embodiment> <Overview> Next, a fourth embodiment will be described, which has the same basic configuration as the third embodiment. Therefore, the same components are denoted by the same reference numerals and their description will be omitted, and only the differences will be described. In particular, the configuration of the digital phase shift circuit B and the configuration of the output transmission line 90 are the same as those of the third embodiment, and therefore description thereof will be omitted.

[0146] 8, the output matching circuit 100C according to this embodiment is different from the output matching circuit 100B according to the third embodiment in the shape of the return line 102C. The return line 102C according to this embodiment includes a shift line 102s, a first intersecting line 102c1, a parallel line 102p, a third intersecting line 102c3, a second intersecting line 102c2, and via pads VP11, VP12, VP21, and VP22 (see also FIG. 9).

[0147] FIG. 9 is a perspective view showing a portion of the return line 102C according to this embodiment. As shown in FIGS. 8 and 9, the return line 102C includes a first return line portion 102L1 and a second return line portion 102L2. As shown in FIGS. 8 and 9, the first return line portion 102L1 includes a shift line 102s, a first intersecting line 102c1, a second intersecting line 102c2, and via pads VP11 and VP12. The second return line portion 102L2 includes a parallel line 102p, a third intersecting line 102c3, and via pads VP21 and VP22. The via pads VP21 and VP22 are located at both ends of the second return line portion 102L2. Of the ends of the second return line portion 102L2, the end where the via pad VP21 is located is referred to as a first end (one end), and the end where the via pad VP22 is located is referred to as a second end (the other end).

[0148] The first return line portion 102L1 is formed on a layer (first layer) on which the second intermediate pad 25b (see FIG. 4) of the digital phase shift circuit B is formed. The second return line portion 102L2 is formed on a layer (second layer) different from the layer on which the first return line portion 102L1 is formed. In this embodiment, the second return line portion 102L2 is formed on an outer layer (a layer on the +Z side) than the first return line portion 102L1. As shown in FIG. 9 , the first return line portion 102L1 and the second return line portion 102L2 are electrically connected via a plurality of vias 103.

[0149] That is, the return line 102C has a three-dimensional structure in which the first return line portion 102L1 and the second return line portion 102L2, which are formed on different layers, are connected by the via 103. As will be described in detail later, the reason for giving the return line 102C a three-dimensional structure is to increase the inductance of the return line 102C.

[0150] As in the third embodiment, the front end (-Y side) of the first intersecting line 102c1 is connected to the first end (+X side) of the shift line 102s. As in the third embodiment, the first intersecting line 102c1 has a bent portion CR1 formed therein. The rear end (+Y side) of the first intersecting line 102c1 is a via pad VP11 to which a via 103 is connected (see FIG. 9 ). In a plan view, the via pad VP11 has a rectangular shape with its long sides extending in the intersecting direction Y and its short sides extending in the longitudinal direction X. The via pad VP11 is electrically connected to a via pad VP21 (details of which will be described later) at the first end of the second return line portion 102L2 via a plurality of vias 103.

[0151] The second intersecting line 102c2 is a strip-shaped conductor electrically connected to the second end of the second return line portion 102L2. Similar to the third embodiment, the second intersecting line 102c2 has a bent portion CR2. In a plan view, the second intersecting line 102c2 extends to the right (+X side) at a portion where the second intersecting line 102c2 overlaps with the second end of the second return line portion 102L2, extends from the right end (+X end) of the overlapping portion toward the signal line 101 in the intersecting direction Y, bends to the right (+X side) at the bent portion CR2, and then extends again to approach the signal line 101 in the intersecting direction Y.

[0152] The back end (+Y side) of the second intersecting line 102c2 is a via pad VP12 to which a via 103 is connected (see FIG. 9 ). In a plan view, the via pad VP12 has a rectangular shape with long sides extending in the longitudinal direction X and short sides extending in the intersecting direction Y. The via pad VP12 of the second intersecting line 102c2 is electrically connected to a via pad VP22 (details of which will be described later) at a second end of the second return line portion 102L2 via a plurality of vias 103.

[0153] The second return line portion 102L2 is a strip-shaped conductor having a parallel line 102p (narrow line portion) and a third intersecting line 102c3 (narrow line portion). The first end (one end) of the second return line portion 102L2 is a via pad VP21. In this embodiment, the end of the via pad VP21 located on the +Y side is referred to as the first end (one end), and the end located on the -Y side is referred to as the second end (the other end). In this embodiment, the second end (the other end) of the second return line portion 102L2 is a via pad VP22. The end of the via pad VP22 located on the -X side is referred to as the first end (one end), and the end located on the +X side is referred to as the second end (the other end). The parallel line 102p is a linear strip-shaped conductor connected to the first end (+Y side) of the via pad VP21. The parallel line 102p is a conductor having a constant width, a constant thickness, and a predetermined length. The parallel line 102p extends parallel to the signal line 101 (in the longitudinal direction X) from the first end (+Y side) of the via pad VP21. That is, the parallel line 102p in this embodiment extends from the first end (+Y side) of the via pad VP21 toward the right side (+X side). The length of the parallel line 102p is shorter than the length of the signal line 101.

[0154] The third intersecting line 102c3 is a linear strip-shaped conductor that extends from the first end (+X side) of the parallel line 102p toward the signal line 101 in the intersecting direction Y and is connected to the first end (-X side) of the via pad VP22. The third intersecting line 102c3 is a conductor having a constant width, a constant thickness, and a predetermined length. The length of the third intersecting line 102c3 is shorter than the length of the first intersecting line 102c1. A bend CR is formed by the third intersecting line 102c3 and the via pad VP22.

[0155] The widths of the parallel line 102p and the third intersecting line 102c3 are narrower than the widths (lengths of the short sides) of the via pads VP21 and VP22. That is, the second return line portion 102L2 includes the parallel line 102p and the third intersecting line 102c3, which are narrow line portions whose widths are narrower than the other portions. In other words, the portions of the second return line portion 102L2 other than the via pads VP21 and VP22 (the parallel line 102p and the third intersecting line 102c3) are narrow line portions whose widths are narrower than the widths of the via pads VP21 and VP22.

[0156] The via pad VP21 has a rectangular shape with its long sides extending in the transverse direction Y and its short sides extending in the longitudinal direction X. The via pad VP21 is arranged so as to overlap with the via pad VP11 in the vertical direction Z. The via pads VP21 and VP11 are electrically connected by a plurality of vias 103. The via pad VP22 has a rectangular shape with its long sides extending in the longitudinal direction X and its short sides extending in the transverse direction Y. The via pad VP22 is arranged so as to overlap with the via pad VP12 in the vertical direction Z. The via pads VP22 and VP12 are electrically connected by a plurality of vias 103.

[0157] In the via pads VP11, VP12, VP21, and VP22, the vias 103 are arranged along the long sides of the via pads VP11, VP12, VP21, and VP22, respectively. Specifically, the vias 103 are arranged along the intersecting direction Y in the via pads VP11 and VP21, and are arranged along the longitudinal direction X in the via pads VP12 and VP22. In other words, the vias 103 at both ends of the second return line portion 102L2 are arranged so that their arrangement directions are perpendicular to each other.

[0158] The return line 102C according to the present embodiment described above forms a loop line that is convex on the rear side (+Y side), similar to the first to third embodiments, and therefore can achieve the same effects as the first to third embodiments.

[0159] Furthermore, in this embodiment, the return line 102C has a three-dimensional structure in which the first return line portion 102L1 and the second return line portion 102L2, which are formed on different layers, are connected by a via 103 (see FIG. 9 ). Because the via 103 itself has inductance, the return line 102C has the above-described three-dimensional structure, which further increases the inductance of the return line 102C. Furthermore, the portions of the second return line portion 102L2 other than the via pads VP21 and VP22 (the parallel line 102p and the third intersecting line 102c3) are narrow line portions whose widths are smaller than the widths of the via pads VP21 and VP22. This also increases the inductance of the return line 102C.

[0160] Summary As described above, the return line 102C according to this embodiment includes the first return line portion 102L1 formed on the first layer and the second return line portion 102L2 formed on the second layer different from the first layer and electrically connected to the first return line portion 102L1 through the via 103. The first return line portion 102L1 and the second return line portion 102L2 form a single loop and are arranged so that only their ends (via pads VP11, VP12, VP21, VP22) overlap in a planar view, and these ends (via pads VP11, VP12, VP21, VP22) are electrically connected through the via 103. This configuration can further increase the inductance of the return line 102C.

[0161] Fifth Embodiment Overview Next, a fifth embodiment will be described, which has the same basic configuration as the fourth embodiment. Therefore, the same components are denoted by the same reference numerals, and a description thereof will be omitted. Only the differences will be described. In particular, the configuration of the digital phase shift circuit B and the configuration of the output transmission line 90 are the same as those of the fourth embodiment, and therefore a description thereof will be omitted.

[0162] 10 , the output matching circuit 100D according to this embodiment is different from the output matching circuit 100C according to the fourth embodiment in the shape of the return line 102D. The return line 102D according to this embodiment includes a shift line 102s, a first intersecting line 102c1, a fourth intersecting line 102c4, a parallel line 102p, a fifth intersecting line 102c5, a second intersecting line 102c2, and via pads VP11, VP12, VP21, and VP22 (see also FIG. 11 ).

[0163] Furthermore, the portion of the return line 102D according to this embodiment other than the shift line 102s has a shape that is substantially line-symmetrical (or roughly line-symmetrical) with respect to the X direction. Note that the return line 102D does not necessarily have to have a shape that is strictly line-symmetrical with respect to the X direction. The shape of the return line 102D may be slightly different from a shape that is strictly line-symmetrical.

[0164] 11 is a perspective view showing a portion of a return line 102D according to this embodiment. As shown in FIGS. 10 and 11 , the return line 102D according to this embodiment includes a first return line portion 102L1 that is substantially symmetrical with respect to the X direction (excluding the shift line 102s) and a second return line portion 102L2 that is symmetrical with respect to the X direction. The first return line portion 102L1 according to this embodiment includes the shift line 102s, a first intersecting line 102c1, a second intersecting line 102c2, and via pads VP11 and VP12. The second return line portion 102L2 according to this embodiment includes a fourth intersecting line 102c4, a parallel line 102p, a fifth intersecting line 102c5, and via pads VP21 and VP22.

[0165] The first intersecting line 102c1 of the first return line portion 102L1 is a strip-shaped conductor having a bent portion CR1 formed therein, similar to the first intersecting line 102c1 in the fourth embodiment. The first intersecting line 102c1 in this embodiment has a constant width.

[0166] The far end (+Y side) of the first intersecting line 102c1 is a via pad VP11 to which a via 103 is connected (see FIG. 11 ). In a plan view, the via pad VP11 has a rectangular shape with its long sides extending in the intersecting direction Y and its short sides extending in the longitudinal direction X. The via pad VP11 is electrically connected to a via pad VP21 (details of which will be described later) at a first end of the second return line portion 102L2 via a plurality of vias 103.

[0167] The second intersecting line 102c2 of the first return line portion 102L1 is a strip-shaped conductor that is substantially symmetrical to the first intersecting line 102c1 in the X direction. In this embodiment, the second intersecting line 102c2 has a constant width.

[0168] The back end (+Y side) of the second intersecting line 102c2 is a via pad VP12 to which a via 103 is connected (see FIG. 11 ). In a plan view, the via pad VP12 has a rectangular shape with long sides extending in the intersecting direction Y and short sides extending in the longitudinal direction X. The via pad VP12 is electrically connected to a via pad VP22 (details of which will be described later) at a second end of the second return line portion 102L2 via a plurality of vias 103.

[0169] The second return line portion 102L2 is a strip-shaped conductor having a parallel line 102p, a fourth intersecting line 102c4, and a fifth intersecting line 102c5. A first end (one end) of the second return line portion 102L2 is a via pad VP21. A second end (the other end) of the second return line portion 102L2 is a via pad VP22. The parallel line 102p is a conductor having a constant width, a constant thickness, and a predetermined length. In this embodiment, the parallel line 102p extends, in a plan view, from the left side edge (-X side) of the far end of the first intersecting line 102c1 to the right side edge (+X side) of the far end of the second intersecting line 102c2.

[0170] The fourth intersecting line 102c4 is a linear strip-shaped conductor that extends from the second end (-X side) of the parallel line 102p toward the signal line 101 in the intersecting direction Y. The end on the near side (-Y side) of the fourth intersecting line 102c4 is a via pad VP21 (see FIG. 11). The fifth intersecting line 102c5 is a linear strip-shaped conductor that extends from the first end (+X side) of the parallel line 102p toward the signal line 101 in the intersecting direction Y. The end on the near side (-Y side) of the fifth intersecting line 102c5 is a via pad VP22 (see FIG. 11). The width of the parallel line 102p is narrower than the widths of the fourth intersecting line 102c4 and the fifth intersecting line 102c5. The fourth intersecting line 102c4 and the fifth intersecting line 102c5 have the same length. The width of the parallel line 102p is narrower than the width of the fourth intersecting line 102c4 and the fifth intersecting line 102c5 in order to increase the inductance of the return line 102D.

[0171] In a plan view, the via pad VP21 has a rectangular shape with its long sides extending in the transverse direction Y and its short sides extending in the longitudinal direction X. The via pad VP21 is arranged so as to overlap with the via pad VP11 in the vertical direction Z. The via pads VP21 and VP11 are electrically connected by a plurality of vias 103. The via pad VP22 has a rectangular shape with its long sides extending in the transverse direction Y and its short sides extending in the longitudinal direction X in a plan view. The via pad VP22 is arranged so as to overlap with the via pad VP12 in the vertical direction Z. The via pads VP22 and VP12 are electrically connected by a plurality of vias 103.

[0172] In the via pads VP11, VP12, VP21, and VP22, the vias 103 are arranged along the long sides of the via pads VP11, VP12, VP21, and VP22, respectively. Specifically, the vias 103 are arranged in the via pads VP11, VP21 and the via pads VP12, VP22 so as to extend along the intersecting direction Y. In other words, the vias 103 at both ends of the second return line portion 102L2 are arranged so that their arrangement directions are parallel to each other.

[0173] <<Function>> The return line 102D according to the present embodiment described above, like the first to fourth embodiments, forms a loop line that is convex toward the rear (+Y side). Therefore, the same effects as those of the first to fourth embodiments can be obtained. Furthermore, like the fourth embodiment, the return line 102D according to the present embodiment has a three-dimensional structure in which the first return line portion 102L1 and the second return line portion 102L2, which are formed on different layers, are connected by the via 103. Therefore, the same effects as those of the fourth embodiment can be obtained.

[0174] 10 and 11, the via pad VP11 and the via pad VP12 are connected by a second return line portion 102L2 having a U-shape. The width of the parallel line 102p is narrower than the widths of the fourth intersecting line 102c4 and the fifth intersecting line 102c5. This allows the inductance of the return line 102D to be further increased.

[0175] The technical scope of the present invention is not limited to the first to fifth embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

[0176] <First to Fourth Modifications> <Overview> For example, in the first to fifth embodiments, the front edge (-Y side) of the second crossing line 102c2 of the output matching circuits 100 to 100D is connected to the rear edge (+Y side) of the ground layer 92 of the output transmission line 90, thereby achieving electrical connection between the return line 102 to 102D and the output-side ground conductor (the ground layer 92 in the first to fifth embodiments). However, the specific aspect of the electrical connection between the return line 102 to 102D and the output-side ground conductor is not limited to this and can be modified as appropriate. Furthermore, in the first to fifth embodiments, the output transmission line 90 constitutes a microstrip line, but the configuration of the output transmission line 90 is not limited to this and can be modified as appropriate.

[0177] The first to fourth modifications described in detail below relate to specific aspects of the electrical connection between the return lines 102 to 102D and the output-side ground conductor and to the configuration of the output transmission line 90. The first to fourth modifications will be described below on the premise of the output matching circuit 100 according to the first embodiment. That is, the description will be given assuming that the return line 102 includes a shift line 102s, a first intersecting line 102c1, a parallel line 102p, and a second intersecting line 102c2 (see FIG. 1 ). However, the first to fourth modifications may also be applied to the output matching circuits 100A to 100D according to the second to fifth embodiments.

[0178] <First Modification> Fig. 12 is a plan view showing a part of an output matching circuit 100 and a part of an output transmission line 90 according to a first modification of the present invention. Fig. 13 is a cross-sectional view taken along line XIII-XIII shown in Fig. 12. Fig. 14 is a cross-sectional view taken along line XIV-XIV shown in Fig. 12.

[0179] As shown in FIG. 12, the output matching circuit 100 according to the first modification further includes a ground conductor 104 and a pair of pads 105a and 105b in addition to the above-described lines (such as the second intersecting line 102c2).

[0180] Of the pair of pads 105a, 105b, the first pad 105a is a rectangular flat conductor connected to the front edge (-Y side) of the second intersecting line 102c2, as shown in Fig. 12. The long sides of the first pad 105a extend in the intersecting direction Y, and the short sides of the first pad 105a extend in the longitudinal direction X. As shown in Fig. 13, the first pad 105a is formed on the layer on which the second intersecting line 102c2 is formed.

[0181] 12, the second pad 105b of the pair of pads 105a, 105b is a rectangular flat conductor provided on the opposite side of the first pad 105a in the Y direction as viewed from the signal line 91. The long sides of the second pad 105b extend in the intersecting direction Y, and the short sides of the second pad 105b extend in the longitudinal direction X. As shown in FIG. 13, the second pad 105b is formed on the layer on which the second intersecting line 102c2 and the first pad 105a are formed.

[0182] 12, the ground conductor 104 is a plate-shaped conductor extending in the longitudinal direction X and the transverse direction Y. As shown in FIGS. 13 and 14, the ground conductor 104 is disposed below the pair of pads 105a, 105b and the ground layer 92 at a predetermined distance.

[0183] As shown in Fig. 12 , the ground conductor 104 overlaps with a pair of pads 105 a, 105 b in a plan view. As shown in Fig. 12 and Fig. 13 , the ground conductor 104 is connected to the pair of pads 105 a, 105 b via a plurality of connecting conductors 50. Also, as shown in Fig. 12 , the ground conductor 104 overlaps with the left (−X side) end of the ground layer 92 in a plan view. As shown in Fig. 12 and Fig. 14 , the ground conductor 104 is electrically connected to the left (−X side) end of the ground layer 92 via a plurality of connecting conductors 50.

[0184] That is, in the first modification, the return line 102 of the output matching circuit 100 and the output-side ground conductor (ground layer 92) of the output transmission line 90 are electrically connected via the first pad 105a, the ground conductor 104, and the plurality of connecting conductors 50. Because the connecting conductors 50 have inductance, such a connection configuration allows the return line 102 to be shortened by the amount of the inductance of the connecting conductors 50. This allows the output matching circuit 100 to be made smaller.

[0185] Second Modification FIG. 15 is a plan view showing a part of an output matching circuit 100 and a part of an output transmission line 90 according to a second modification of the present invention.

[0186] The output matching circuit 100 according to the second modification further includes a connection portion 106 in addition to the ground conductor 104 and the pair of pads 105a, 105b according to the first modification.

[0187] The connection portion 106 is a conductor formed on the layer on which the first pad 105a and the ground layer 92 are formed. The connection portion 106 is provided between the first pad 105a and the ground layer 92 in the longitudinal direction X, and mechanically and electrically connects the first pad 105a and the ground layer 92. By introducing such a connection portion 106, it is possible to reduce loss occurring between the second cross line 102c2 and the ground layer 92 compared to the first modification.

[0188] <Third Modification> Fig. 16 is a plan view showing a part of an output matching circuit 100 and a part of an output transmission line 90 according to a third modification of the present invention. Fig. 17 is a cross-sectional view taken along line XVII-XVII shown in Fig. 16.

[0189] 16, the output matching circuit 100 according to the third modification has the same shape as the output matching circuit 100 according to the first modification (see FIG. 12). In the third modification, as in the first modification, the return line 102 of the output matching circuit 100 and the output-side ground conductor (ground layer 92) of the output transmission line 90 are electrically connected via the first pad 105a, the ground conductor 104, and the plurality of connecting conductors 50.

[0190] Unlike the first modification, the output transmission line 90 according to the third modification constitutes a so-called grounded coplanar line. Specifically, as shown in Figures 16 and 17, the output transmission line 90 according to the third modification further includes a pair of ground lines 93a, 93b and a pair of intermediate conductor layers 94a, 94b in addition to the signal line 91 and ground layer 92 of the first modification. The pair of ground lines 93a, 93b are arranged on both sides of the signal line 91 with a gap between them.

[0191] 16 and 17 , the first ground line 93a is a long, plate-like conductor having a constant width, a constant thickness, and a predetermined length. The first ground line 93a extends in the longitudinal direction X parallel to the signal line 91 and is located on the far side (+Y side) of the signal line 91.

[0192] 16 and 17, the second ground line 93b is a long, plate-like conductor having a constant width, a constant thickness, and a predetermined length. The first ground line 93a extends in the longitudinal direction X parallel to the signal line 91 and is located on the near side (-Y side) of the signal line 91.

[0193] 17 , of the pair of intermediate conductor layers 94 a, 94 b, the first intermediate conductor layer 94 a is located between the first ground line 93 a and the ground layer 92 in the vertical direction Z. The first intermediate conductor layer 94 a is also located at a position spaced a predetermined distance from both the first ground line 93 a and the ground layer 92.

[0194] The first ground line 93a and the first intermediate conductor layer 94a are connected by a connecting conductor 50. The first intermediate conductor layer 94a and the ground layer 92 are also connected by the connecting conductor 50. As a result, the ground layer 92 is connected to the first ground line 93a via the connecting conductor 50 and the first intermediate conductor layer 94a.

[0195] Although detailed illustration is omitted, the first intermediate conductor layer 94a extends in the longitudinal direction X along the first ground line 93a. A plurality of connection conductors 50 are provided to connect the first ground line 93a and the first intermediate conductor layer 94a, and these connection conductors 50 are arranged along the first ground line 93a. Similarly, a plurality of connection conductors 50 are provided to connect the first intermediate conductor layer 94a and the ground layer 92, and these connection conductors 50 are arranged along the first intermediate conductor layer 94a.

[0196] 17, the second intermediate conductor layer 94b is located between the second ground line 93b and the ground layer 92 in the vertical direction Z. The second intermediate conductor layer 94b is also located at a predetermined distance from both the second ground line 93b and the ground layer 92.

[0197] The second ground line 93b and the second intermediate conductor layer 94b are connected by a connecting conductor 50. The second intermediate conductor layer 94b and the ground layer 92 are also connected by a connecting conductor 50. As a result, the ground layer 92 is connected to the second ground line 93b via the connecting conductor 50 and the second intermediate conductor layer 94b.

[0198] Although detailed illustration is omitted, the second intermediate conductor layer 94b extends in the longitudinal direction X along the second ground line 93b. A plurality of connection conductors 50 are provided to connect the second ground line 93b and the second intermediate conductor layer 94b, and these connection conductors 50 are arranged along the second ground line 93b. Similarly, a plurality of connection conductors 50 are provided to connect the second intermediate conductor layer 94b and the ground layer 92, and these connection conductors 50 are arranged along the second intermediate conductor layer 94b.

[0199] <Fourth Modification> Fig. 18 is a plan view showing a part of an output matching circuit 100 and a part of an output transmission line 90 according to a fourth modification of the present invention. Fig. 19 is a cross-sectional view taken along line XIX-XIX shown in Fig. 18.

[0200] 18, the output transmission line 90 according to the fourth modification has the same shape as the output transmission line 90 according to the third modification (see FIG. 16). In the fourth modification, as in the third modification, the return line 102 of the output matching circuit 100 and the output-side ground conductor (ground layer 92) of the output transmission line 90 are electrically connected via the first pad 105a, the ground conductor 104, and the plurality of connecting conductors 50.

[0201] As shown in Figures 18 and 19, the output matching circuit 100 of the fourth modified example further has a pair of upper pads 107a and 107b (a first upper pad 107a and a second upper pad 107b) and a pair of intermediate pads 108a and 108b (a first intermediate pad 108a and a second intermediate pad 108b), in addition to the ground conductor 104 and a pair of pads 105a and 105b of the third modified example.

[0202] 19 , the first upper pad 107a and the first intermediate pad 108a are disposed above the first pad 105a. The first upper pad 107a, the first intermediate pad 108a, and the first pad 105a overlap one another in a plan view. The first upper pad 107a, the first intermediate pad 108a, and the first pad 105a are aligned in this order from the top (+Z side) to the bottom (−Z side), and are spaced apart in the vertical direction Z.

[0203] The first upper pad 107a and the first intermediate pad 108a are electrically and mechanically connected by a plurality of connecting conductors 50. The first intermediate pad 108a and the first pad 105a are also electrically and mechanically connected by a plurality of connecting conductors 50. As shown in FIG. 18 , the first upper pad 107a is formed in the layer in which the first ground line 93a is formed, and is electrically and mechanically connected to the left edge (−X side) of the first ground line 93a. As a result, the first ground line 93a and the second cross line 102c2 are electrically connected via the first upper pad 107a, the first intermediate pad 108a, the first pad 105a, and the connecting conductors 50 (see also FIG. 19 ).

[0204] 19 , the second upper pad 107b and the second intermediate pad 108b are disposed above the second pad 105b. The second upper pad 107b, the second intermediate pad 108b, and the second pad 105b overlap one another in a plan view. The second upper pad 107b, the second intermediate pad 108b, and the second pad 105b are aligned in this order from the top (+Z side) to the bottom (−Z side), and are spaced apart in the vertical direction Z.

[0205] The second upper pad 107b and the second intermediate pad 108b are electrically and mechanically connected by a plurality of connecting conductors 50. The second intermediate pad 108b and the second pad 105b are electrically and mechanically connected by a plurality of connecting conductors 50. As shown in FIG. 18 , the second upper pad 107b is formed in the layer in which the second ground line 93b is formed, and is electrically and mechanically connected to the left edge (−X side) of the second ground line 93b.

[0206] <Fifth to Seventh Modifications> <Overview> The fifth to seventh modifications described below, like the first to fourth modifications, are modifications related to the specific aspects of the electrical connection between the return lines 102 to 102D and the output-side ground conductor and the configuration of the output transmission line 90. However, unlike the return line 102 of the first to fourth modifications, the return line 102′ (e.g., the shift line 102s′, the first crossing line 102c1′, the parallel line 102p′, and the second crossing line 102c2′) of the fifth to seventh modifications are formed in the same layer as the signal lines 10, 101, and 91 (see FIG. 20 ). The shift line 102s′ is connected to the upper pad 25 of the digital phase shift circuit B. Note that the fifth to seventh modifications will also be described below based on the output matching circuit 100 of the first embodiment. However, the fifth to seventh modifications may be applied to the output matching circuits 100A to 100D according to the second to fifth embodiments.

[0207] <Fifth Modification> Fig. 20 is a plan view showing a part of a digital phase shift circuit B according to a fifth modification, an output matching circuit 100', and an output transmission line 90. Fig. 21 is a cross-sectional view taken along line XXI-XXI shown in Fig. 20. Note that Fig. 20 omits the illustration of components of the digital phase shift circuit B other than the signal line 10, upper pads 24 and 25, and second ground conductor 32.

[0208] As shown in FIG. 20, an output transmission line 90 according to the fifth modification has a signal line 91 and a ground layer 92, similar to the first embodiment, and forms a microstrip line (see FIG. 1).

[0209] As shown in Figures 20 and 21, the output matching circuit 100' according to the fifth modified example further includes, in addition to the above-mentioned lines (such as the second cross line 102c2'), a pair of pads 105a', 105b', a pair of intermediate pads 109a, 109b, and a plurality of connecting conductors 50.

[0210] Of the pair of pads 105a', 105b', the first pad 105a' is a rectangular flat conductor connected to the front edge (-Y side) of the second intersecting line 102c2', as shown in Fig. 20. The long sides of the first pad 105a' extend in the intersecting direction Y, and the short sides of the first pad 105a' extend in the longitudinal direction X. As shown in Fig. 21, the first pad 105a' is formed on the layer on which the second intersecting line 102c2' and the signal line 91 are formed.

[0211] 20, the second pad 105b' of the pair of pads 105a', 105b' is a rectangular flat conductor provided on the opposite side of the first pad 105a' in the Y direction as viewed from the signal line 91. The long sides of the second pad 105b' extend in the intersecting direction Y, and the short sides of the second pad 105b' extend in the longitudinal direction X. As shown in FIG. 21, the second pad 105b' is formed on the layer on which the second intersecting line 102c2', the first pad 105a', and the signal line 91 are formed.

[0212] Of the pair of intermediate pads 109a, 109b, the first intermediate pad 109a is disposed below the first pad 105a', as shown in FIG. 21 . The first pad 105a' and the first intermediate pad 109a overlap each other in a plan view. Furthermore, as shown in FIGS. 20 and 21 , the ground layer 92 according to the fifth modification is provided with a first protrusion 92a. The first protrusion 92a protrudes toward the rear (+Y side) at the left (-X side) end of the ground layer 92 and overlaps with at least a portion of the first pad 105a' and the first intermediate pad 109a in a plan view. As shown in FIG. 21 , the first pad 105a', the first intermediate pad 109a, and the ground layer 92 are aligned in this order from the upper side (+Z side) to the lower side (-Z side), and are spaced apart in the vertical direction Z.

[0213] The first pad 105a′ and the first intermediate pad 109a are electrically and mechanically connected by a plurality of connecting conductors 50. Furthermore, the first intermediate pad 109a and the ground layer 92 (first protrusion 92a) are electrically and mechanically connected by a plurality of connecting conductors 50. As a result, the second cross line 102c2′ and the ground layer 92, which is the ground conductor (output-side ground conductor) of the output transmission line 90, are electrically connected via the first pad 105a′, the first intermediate pad 109a, and the connecting conductors 50.

[0214] Of the pair of intermediate pads 109a, 109b, the second intermediate pad 109b is disposed below the second pad 105b', as shown in FIG. 21 . The second pad 105b' and the second intermediate pad 109b overlap each other in a plan view. Furthermore, as shown in FIGS. 20 and 21 , the ground layer 92 according to the fifth modification has a second protruding portion 92b that protrudes toward the front (-Y side) at the left (-X side) end of the ground layer 92 and overlaps with at least a portion of the second pad 105b' and the second intermediate pad 109b in a plan view. As shown in FIG. 21 , the second pad 105b', the second intermediate pad 109b, and the ground layer 92 are aligned in this order from the upper side (+Z side) to the lower side (-Z side) and are spaced apart in the vertical direction Z.

[0215] The second pad 105b′ and the second intermediate pad 109b are electrically and mechanically connected by a plurality of connecting conductors 50. In addition, the second intermediate pad 109b and the ground layer 92 (second protruding portion 92b) are electrically and mechanically connected by a plurality of connecting conductors 50.

[0216] However, the output matching circuit 100′ does not necessarily have to include the second pad 105b′, the second intermediate pad 109b, and the connecting conductor 50 connecting them. In this case, the ground layer 92 does not necessarily have to be provided with the second protrusion 92b.

[0217] <Sixth Modification> Fig. 22 is a plan view showing a part of an output matching circuit 100' according to a sixth modification of the present invention and a part of an output transmission line 90. Fig. 23 is a cross-sectional view taken along line XXIII-XXIII shown in Fig. 22.

[0218] 22 and 23 , the output transmission line 90 according to the sixth modification constitutes a grounded coplanar line, similar to the third modification (see FIG. 16 ). That is, the output transmission line 90 according to the sixth modification includes a signal line 91, a ground layer 92, a pair of ground lines 93 a and 93 b, a pair of intermediate conductor layers 94 a and 94 b, and a plurality of connecting conductors 50. As shown in FIG. 23 , the plurality of connecting conductors 50 electrically connect the ground layer 92, the first ground line 93 a, and the first intermediate conductor layer 94 a, and electrically connect the ground layer 92, the second ground line 93 b, and the second intermediate conductor layer 94 b.

[0219] 22 and 23 , in the sixth modification, the near end edge (−Y side) of the second crossing line 102c2′ is connected to the far side edge (+Y side) of the first ground line 93a of the output transmission line 90. Therefore, the return line 102′ including the second crossing line 102c2′ is electrically connected to the ground layer 92 (output-side ground conductor) of the output transmission line 90 via the first ground line 93a, the first intermediate conductor layer 94a, and the plurality of connecting conductors 50.

[0220] <Seventh Modification> Fig. 24 is a plan view showing a part of an output matching circuit 100' according to a seventh modification of the present invention and a part of an output transmission line 90. Fig. 25 is a cross-sectional view taken along line XXV-XXV shown in Fig. 24.

[0221] 24, the seventh modification is the sixth modification except for the shapes of the ground layer 92 and intermediate conductor layers 94a and 94b (not shown in FIG. 24) (see FIG. 22). Specifically, the ground layer 92 and intermediate conductor layers 94a and 94b according to the seventh modification are located only at the left end (−X side) of the output transmission line 90, and do not extend in the longitudinal direction X along the signal line 91 and the ground lines 93a and 93b (the intermediate conductor layers 94a and 94b are not shown).

[0222] Therefore, the output transmission line 90 configures a coplanar line except for the left end (-X side) where the ground layer 92 and intermediate conductor layers 94a and 94b are arranged (see FIG. 25). In the seventh modification, the return line 102' including the second crossing line 102c2' is electrically connected to the output-side ground conductors of the output transmission line 90 (ground lines 93a and 93b in the seventh modification) via the ground layer 92, the intermediate conductor layers 94a and 94b, and the connecting conductor 50.

[0223] <Other Modifications> Other modifications will be described below.

[0224] For example, the shape of the loop line RP of the digital phase shift circuit B can be modified as appropriate as long as it is a loop shape that is convex in the direction away from the signal line 10 in the intersecting direction Y. Furthermore, one or more digital phase shift circuits B may be cascade-connected to the input end (left side (−X side) end) of the digital phase shift circuit B illustrated in FIG. 1 etc. In other words, the connection structure A may have a connection string including a plurality of digital phase shift circuits B cascade-connected in the longitudinal direction X. Then, the output matching circuit 100 may be connected to the output end (right side (+X side) end) of the connection string.

[0225] Furthermore, for example, the output transmission line 90 (see FIGS. 16 and 17 ) according to the third modification may have, in addition to the above-described ground layer 92 (lower ground layer), an upper ground layer disposed above the signal line 91 and the pair of ground wires 93 a, 93 b at a predetermined distance. That is, the output transmission line 90 may have a triplate line structure in which the signal line 91 is sandwiched between two ground layers. Alternatively, the output transmission line 90 may have only one of the upper and lower ground layers. That is, it is sufficient that a ground layer is disposed above or below the signal line 91 and the pair of ground wires 93 a, 93 b. The return line 102 is electrically connected to the disposed ground layer (output-side ground conductor).

[0226] In the illustrated example, the output transmission line 90 extends linearly in the longitudinal direction X, but the output transmission line 90 may be bent in plan view.

[0227] In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate, without departing from the spirit of the present invention.

[0228] B...Digital phase shift circuit 10...Signal line (circuit side signal line) 21...First line 21p1...First parallel line 22...Second line 22p2...Second parallel line RP...Loop line 31...First ground conductor 32...Second ground conductor 41...First electronic switch 42...Second electronic switch 90...Output transmission line 91...Signal line (output side signal line) 92...Ground layer (output side ground conductor) 93a, 93b...Ground line (output side ground conductor) 100, 100', 100A, 100B, 100C, 100D...Output matching circuit 101...Signal line 102...Return line 102c1...First intersecting line 102p...Parallel line 102c2...Second intersecting line 102b...Bent line 102L1...first return line portion 102L2...second return line portion 103...via X...longitudinal direction Y...crossing direction

Claims

1. A digital phase shift circuit and an output transmission line are electrically connected, and the digital phase shift circuit includes a first line including a circuit side signal line, a first parallel line extending parallel to the circuit side signal line, a second parallel line extending parallel to the circuit side signal line, and a second line including a loop-shaped loop line extending from a first end of the second parallel line to near a second end of the second parallel line and having a convex shape in a direction away from the circuit side signal line in a cross direction crossing the longitudinal direction of the circuit side signal line, and an output matching circuit comprising: a first ground conductor electrically connected to the first end of a row line; a second ground conductor connected to a first end of the second line; a first electronic switch provided between the second end of the first parallel line and the second ground conductor; and a second electronic switch provided between the second end of the second parallel line and the second ground conductor, wherein the circuit-side signal line is located between the first parallel line and the second parallel line in the digital phase shift circuit, and the output transmission line has an output-side signal line and an output-side ground conductor; the output matching circuit further comprising: a signal line connected to the circuit-side signal line and the output-side signal line; and a return line electrically connected to the second ground conductor and the output-side ground conductor, the return line being longer than the signal line.

2. The output matching circuit according to claim 1, wherein a cross-sectional area of ​​the return line is smaller than a cross-sectional area of ​​the loop line.

3. The output matching circuit according to claim 1 or 2, wherein the return line is in the form of a loop that is convex in the direction away from the signal line in the crossing direction.

4. The output matching circuit of claim 3, wherein the return line includes, in a plan view, a first intersecting line extending from near a first end of the signal line in the intersecting direction away from the signal line, a parallel line extending from a first end of the first intersecting line in parallel to the signal line, and a second intersecting line extending from the first end of the parallel line in the intersecting direction toward the signal line.

5. The output matching circuit according to claim 3, wherein the return line includes, in a plan view, a first intersecting line extending from near a first end of the signal line in the intersecting direction away from the signal line, a parallel line extending from the first end of the first intersecting line in parallel to the signal line and having a length shorter than that of the signal line, and a bent line connected to the first end of the parallel line, extending a length shorter than that of the first intersecting line so as to approach the signal line in the intersecting direction, and then extending parallel to the signal line in the intersecting direction away from the first intersecting line.

6. The output matching circuit according to claim 3, wherein a cross-sectional area of ​​at least a part of the return line is smaller than a cross-sectional area of ​​the signal line.

7. The output matching circuit of any one of claims 3 to 6, wherein the return line includes a first return line section formed in a first layer, and a second return line section electrically connected to the first return line section through a via and formed in a second layer different from the first layer, the first return line section and the second return line section forming a single loop and being arranged such that only their ends overlap in a planar view, and the ends are electrically connected through the via.

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