JP5053245B2 - 180 degree hybrid - Google Patents

Description

  The present invention relates to a 180-degree hybrid structure used in a microwave band and a millimeter-wave band, and relates to a 180-degree hybrid having a small size and a low profile.

  The 180 degree hybrid circuit is widely used for signal processing in the microwave band and the millimeter wave band. As a 180-degree hybrid circuit realized by a waveguide circuit, a circuit called Magic T is known as a circuit that can realize a broadband phase characteristic. However, since the magic T by the waveguide is large in a three-dimensional circuit, it cannot be used by being mounted on a printed wiring board.

On the other hand, if the magic T is formed by using a dielectric waveguide in which the waveguide is reduced in size by a dielectric, the size can be reduced as compared with a circuit using a metal waveguide. However, if the device is simply downsized, it is still a three-dimensional circuit and cannot be mounted on a printed wiring board. This can be said to be inconvenient for recent communication devices that are becoming smaller and lighter.
JP-A-11-68422 Japanese Patent Laid-Open No. 2005-20643 JP 2001-156510 A

  The present invention provides a magic T that has excellent characteristics as a 180-degree hybrid circuit and that can be mounted on a printed wiring board with a dielectric waveguide having a small size.

  The present invention solves the above problems by combining a dielectric waveguide and a microstrip. That is, the entire surface other than the signal input / output portion is composed of a dielectric block covered with a conductor film, and one end side in the signal propagation direction is branched into two to have three ports, and at the bottom of the branched portion Dielectric waveguide having a slot through which a dielectric is exposed, the tip portion is opened and terminated, and the opened and terminated tip portion faces the slot of the dielectric waveguide with a space therebetween A microstrip comprising a cavity made of a conductor wall surrounding the periphery of the tip portion of the microstrip, the slot of the dielectric waveguide, except for a portion drawn out for connection to an external circuit of the microstrip It has a special feature.

  According to the present invention, the magic T, which is a three-dimensional circuit commonly used in metal waveguides, is reduced in size by a dielectric waveguide and transformed into a planar low-profile structure on a printed wiring board. Can be implemented.

  An H-shaped slot is provided at a branch portion at the bottom of an H-plane branch circuit (T branch or Y branch) using a dielectric waveguide. The slot has a longitudinal direction that is parallel to the symmetry plane (E plane) of the branch circuit and maintains symmetry. Further, open-ended microstrips formed on the printed wiring board are arranged close to each other with a gap so that coupling occurs to this slot.

  Conductor walls are provided so that cavities are formed to accommodate the slots and microstrips. The surrounding conductor wall is only partially removed by the microstrip line. Conductor walls are also provided at the periphery of the printed circuit board at the coupling portion, and constitute a cavity together with a parallel surface formed by the printed circuit board and the bottom surface of the dielectric waveguide.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a basic structure of a 180-degree hybrid according to the present invention. An H-plane branch circuit having three ports is formed by the dielectric waveguide 10, and a slot 11 is formed on the bottom surface thereof. In this dielectric waveguide branch circuit, a conductor film is formed on the entire surface of a dielectric material except for a port opening and a slot. The slot 11 on the bottom is coupled to the probe 15 formed at the open end of the microstrip 14 formed on the printed wiring board 13 which is a mounting board via a gap. This coupling portion is surrounded by a conductor wall 17, and sandwiched from above and below by the conductor on the bottom surface of the dielectric waveguide 10 and the conductor on the bottom surface of the printed wiring board 13, so that the coupling portion is accommodated in the cavity. Become.

  The dielectric waveguide 10 and printed wiring board 13 shown in FIG. 1 are combined to form a 180 degree hybrid as shown in FIG. In the example of FIG. 1, the slot 11 provided on the bottom surface of the dielectric waveguide 10 has an H shape so that the coupling amount with the microstrip 14 is increased. Further, the probe 15 having the microstrip 14 as an open end has a narrow line width at the tip for impedance matching and is bent so as to be accommodated on the bottom surface of the dielectric waveguide 10 as shown in FIG. It has been.

  4 and 5 are configuration diagrams of an actual connection structure. The printed wiring board 43 on which the microstrip 44 is formed is provided with a row of via holes 48 around the connection portion, and serves as a substitute for the conductor wall. The H plane branch by the dielectric waveguide is fixed on the printed wiring board 43 through the spacer 49. The spacer 49 may be made of a conductive material, but may be made of a resin material or a printed wiring board material and a conductor is plated on the inner wall. In any case, it suffices if the open end portion of the microstrip and the opposing portion of the slot are accommodated by the conductor wall. Each port of the dielectric waveguide is converted into a microstrip using a “dielectric waveguide-microstrip conversion structure” as shown in Japanese Patent No. 4133747, and mounted on a printed wiring board for use. be able to. Alternatively, it is possible to connect a dielectric waveguide filter or a dielectric waveguide antenna to each port.

Hereinafter, the operation of the 180-degree hybrid according to the present invention will be described. In FIG. 6, the operation when there is a TE ₁₀ mode input from Port 3 and Port 4 will be described. When the inputs from Port 3 and Port 4 are in reverse phase, the E plane passing through the center of Port 2 of the dielectric waveguide becomes an electric wall having a potential of zero. In this case, the TE ₁₀ mode does not propagate to Port2. Since the electric field is orthogonal on the E-plane which is an electric wall, the slot formed in the bottom surface of the dielectric waveguide branch is excited by this orthogonal electric field, and energy propagates to the microstrip coupled to the slot. By adjusting the dimensions of each part and taking impedance matching, the combined power input from Port3 and Port4 is output to Port1.

  When the inputs from Port 3 and Port 4 are in phase, the E plane becomes a magnetic wall and all electric field vectors are parallel to the E plane. In this case, there is no electric field that excites the slot at the bottom of the dielectric waveguide branch, and no energy propagates to the microstrip. By adjusting the dimensions of each part and taking impedance matching, the combined power input from Port3 and Port4 is output to Port2.

  Since this passive circuit has reversibility, the operation is as follows when the input and output ports are switched. When there is input from Port1, no output appears in Port2, power appears distributed to Port3 and Port4, and the phase is reversed. When there is an input from Port2, no output appears on Port1, and power appears on Port3 and Port4 in the same phase.

  The result of having calculated the S parameter of the structure by this invention by the high frequency electromagnetic field simulator is shown. In this calculation, the dielectric waveguide is made of a material having a relative dielectric constant of 4.5, and the cross-sectional dimension is 4.5 mm × 2 mm.

FIG. 7 shows the coupling amounts S ₃₁ and S ₄₁ between the port 1 and the ports 3 and 4 and the coupling amounts S ₃₂ and S ₄₂ between the port 2 and the ports 3 and 4. The amount of coupling is -3dB within the operating band from 23GHz to 29GHz. FIG. 8 shows the isolation between the ports. In ideal operation, there is no coupling between port 1 and port 2 and port 3 and port 4. This calculation result shows that in the frequency range from 23 GHz to 29 GHz, S ₂₁ is −29 dB or more and S ₄₃ is −13 dB or more, and sufficient isolation is obtained. As shown in FIG. 9, the return loss characteristic of each port is -12 dB or more in the range from 23 GHz to 29 GHz.

  10 and 11 show the calculation results of the phase characteristics. When there is an input from port 1, the outputs generated at ports 3 and 4 are ideally inverted. In this structure, the phase difference between port 3 and port 4 is 180 ° ± 2 ° in the range of 23 GHz to 29 GHz. When there is an input from port 2, the output generated at port 3 and port 4 will ideally have a phase difference of zero. However, in this calculation result, a phase difference of ± 2 degrees is obtained in the range of 23 GHz to 29 GHz. It has become.

  As can be seen from the above calculation results, this circuit structure operates as a good 180 degree hybrid circuit in the range of 23 GHz to 29 GHz.

  The 180-degree hybrid according to the present invention can be used as a 180-degree hybrid circuit having good characteristics in the microwave band and the millimeter wave band as described above.

The exploded perspective view which shows the Example of this invention The exploded perspective view which shows the Example of this invention The partial top view which shows the Example of this invention Exploded perspective view showing another embodiment of the present invention. Exploded perspective view showing another embodiment of the present invention. Illustration of operation of the present invention Explanatory diagram of characteristics of 180 degree hybrid according to the present invention Explanatory diagram of characteristics of 180 degree hybrid according to the present invention Explanatory diagram of characteristics of 180 degree hybrid according to the present invention Explanatory diagram of characteristics of 180 degree hybrid according to the present invention Explanatory diagram of characteristics of 180 degree hybrid according to the present invention

Explanation of symbols

10: Dielectric waveguide
11: Slot
13, 43: Printed wiring board
14, 44: Microstrip
15: Probe
17: Conductor wall
48: Beer hall
49: Spacer

Claims (5)

The entire surface other than the signal input / output portion is composed of a dielectric block covered with a conductor film, and one end side in the signal propagation direction is branched into two to have three ports, and a dielectric is formed on the bottom surface of the branched portion. A dielectric waveguide with a slot through which the
A microstrip having a distal end open and terminating, the open and terminating distal end facing the slot of the dielectric waveguide at a distance;
A cavity comprised of a conductor wall surrounding the periphery of the tip portion of the microstrip with the slot of the dielectric waveguide, except for a portion that is drawn out to connect to an external circuit of the microstrip;
A 180 degree hybrid. An H-plane branch circuit is formed in which a T-type or Y-type branch is formed in a dielectric waveguide composed of a dielectric block whose entire surface other than the signal input / output portion is covered with a conductor film. A dielectric waveguide having a slot in which a dielectric is exposed on the bottom surface of
A microstrip having a distal end open and terminating, the open and terminating distal end facing the slot of the dielectric waveguide at a distance;
A cavity comprised of a conductor wall surrounding the periphery of the tip portion of the microstrip with the slot of the dielectric waveguide, except for a portion that is drawn out to connect to an external circuit of the microstrip;
A 180 degree hybrid.   The 180-degree hybrid according to claim 1 or 2, wherein the slot has an H shape whose longitudinal direction is parallel to the symmetry plane of the branch circuit and has symmetry.   The 180-degree hybrid according to claim 1, wherein the microstrip is provided on a printed wiring board, and a conductor film surrounding the periphery of the microstrip is connected to the ground conductor on the back surface to form a cavity.   The microstrip is provided on a printed wiring board, and a conductor surrounding the periphery of the tip of the microstrip is connected to the ground conductor on the back surface and a via hole, and a slot is formed between the dielectric waveguide and the printed wiring board. The 180-degree hybrid according to claim 1 or 2, wherein a cavity is formed by arranging a spacer of a conductive plate having a gap at an opposing position.

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