JP4707187B2 - High frequency circuit - Google Patents

Description

  The present invention relates to a high-frequency circuit, and more particularly, to a high-frequency circuit mounting technique for realizing good impedance matching between a signal source circuit of a high-frequency signal in a microwave band and a millimeter wave band and a load circuit.

  This type of high-frequency circuit is used, for example, for connection between a radio circuit unit of a base station and an antenna in a mobile communication system. 4 and 5 are diagrams (1) and (2) for explaining the prior art, and FIG. 4 is an antenna (load) for converting the output (signal source) of the high-frequency amplifier circuit from the microstrip line to the electromagnetic wave in the waveguide. The high frequency circuit of the part supplied to is shown. 4A is a mounting plan view of the high-frequency circuit, and FIG. 4B is an a-a ′ cross-sectional view of the circuit.

  This high-frequency circuit is roughly divided into an amplifier substrate 30 in which a high-frequency amplifier (amplifier) 24 is mounted on a dielectric substrate 21, and an antenna substrate 70 for converting a high-frequency signal on the microstrip line 22 into an electromagnetic wave in the waveguide 11. These are fixed at the four corners by screws 15 and washers 6 to a common housing 10 made of aluminum, brass or the like.

  The amplifier 24 and a line conversion electrode (antenna) 25 for converting the output high frequency signal into an electromagnetic wave are connected by a microstrip line 22, where 21 is an intermediate dielectric substrate, and 22 is a surface A microstrip line 23 is a ground conductor on the back side. The ground conductor 23 is cut out at the opening 12 of the rectangular waveguide 11.

  For example, a TE10 mode electromagnetic wave propagates through the waveguide 11, an electric field E is distributed in a direction parallel to the short side direction (E plane), and along a plane (H plane) perpendicular to the electric field. A magnetic field H is distributed. Although not shown, the upper end portion of the waveguide 11 is a short-circuited surface, and the lower end portion is an antenna terminal. By arranging the line conversion electrode 25 at the position of the waveguide opening 12, the electrode 11 25 is magnetically coupled to the electromagnetic wave propagating through the waveguide 11.

  In this type of high frequency circuit, impedance matching between the amplifier 24 and the load (line conversion unit) 25 is important. If sufficient matching is not obtained, loss due to reflection increases or oscillation occurs in some cases. Circuit operation becomes unstable.

  Conventionally, the impedance matching between the characteristic impedance (line width) of the microstrip line 22 and the amplifier circuit 24 and the load circuit 25 has been realized in consideration of only the used frequency (the center frequency of the used band). However, in a design that considers only the frequency used, there is a possibility that sufficient matching may not be obtained for out-of-band frequencies such as harmonic components generated in the amplifier 24 and the like, which may impair circuit performance. This will be specifically described below.

  FIG. 4C shows an electric circuit diagram of the high-frequency circuit. Here, the amplifier 24 and the load 25 are connected by a microstrip line 22 having an electrical length L. Usually, since the characteristic impedance (line width) of the microstrip line 22 is selected to be 50Ω with respect to the operating frequency, the impedance of the line does not change even if the electrical length L increases / decreases. That is, as shown in the Smith chart of FIG. 5A, since the characteristic impedance of the strip line 22 is constant at 50Ω regardless of the electrical length L at the in-band frequency, the output impedance a of the amplifier 24 matched therewith is also obtained. The input impedance b of the load 35 also looks constant at 50Ω regardless of the electrical length L.

  However, as shown in the Smith chart of FIG. 5B, since the characteristic impedance of the microstrip line 22 includes a reactance component with respect to the out-of-band frequency, the output impedance c of the amplifier 24 and the input impedance d of the load 35 are both electrical. As the length L increases / decreases, it changes as shown in the figure. As a result, the performance of the high-frequency circuit may not be sufficiently exhibited or may oscillate, which may cause unexpected characteristic degradation. For this reason, the electrical length L of the microstrip line 22 is the performance of this type of high-frequency circuit. It is an important factor that influences Therefore, in this type of high-frequency circuit, circuit design and mounting design that consider not only the used frequency but also the out-of-band frequency are necessary.

  Conventionally, the electrical length L of the basic design microstrip line 22 is changed by trial and error, or if necessary, an isolator matching only the operating frequency is inserted between stages, or some attenuators are used. We dealt with it by taking isolation between steps.

  FIG. 5C shows an example of a high-frequency circuit after handling. Here, reference numeral 30 ′ denotes an amplifier board in which the electrical length of the microstrip line 22 is shortened, and this is basically dealt with by changing the line length of the amplifier board 30 to recreate the circuit. Reference numeral 40 denotes an isolator substrate that is newly inserted between stages as required, 27 is an isolator circuit, and 28 is a terminator.

Conventionally, there has also been a technique of a power combining amplifier capable of making the total electrical length of a circuit including each amplifier substantially equal by providing each predetermined phase adjustment line for each amplifier provided on a plurality of lines. Known (Patent Document 1).
JP 7-15254 A

  However, according to the above prior art, it is necessary to redesign the high frequency circuit or remake the circuit every time the electrical length L of the strip line is changed, and much time and labor are required until a high frequency circuit having the required performance is obtained. There was a problem that required.

  The present invention has been made in view of the above-described problems of the prior art, and the object of the present invention is to provide a high-frequency signal that can obtain a required amplification performance with a simple configuration and operation even for a high-frequency signal including an out-of-band frequency component. It is to provide a circuit.

  The above problem is solved by the configuration of FIG. That is, the high frequency circuit of the present invention (1) includes an amplification substrate 50 in which an amplification circuit for amplifying a microwave band or millimeter wave band high frequency signal is mounted on a dielectric substrate, and the amplification circuit on the dielectric substrate. Matching is obtained between the amplifying circuit and the load circuit by interposing the load substrate 70 on which the load circuit 25 to which an output high-frequency signal is supplied is mounted, and the amplifying substrate and the load substrate on a dielectric substrate. A strip substrate for mounting a strip line is provided on a common housing 10 so that the strip substrate can be fixed to the common housing 10, and the amplification substrate 50 is connected to a strip line of the line substrate 60a / 60b or 60c having an arbitrary electrical length. In order to connect the strip line of the amplification substrate, the amplification substrate is configured to be slidable with respect to a fixing member to the casing.

  In the present invention (1), since the amplification substrate 50 is configured to be slidable with respect to a fixing member (for example, the screw 15) to the housing, the line substrate 60a having an arbitrary electrical length (line length) between the load substrate 70 and the substrate. / 60b or 60c can be easily sandwiched, and thus an electrical length (line length) that has a required deterrent effect even for out-of-band frequency components existing between the amplifier circuit and the load circuit is easily realized. it can.

  The high frequency circuit of the present invention (2) includes an amplification substrate 50 in which an amplification circuit for amplifying a microwave band or a millimeter wave band high frequency signal is mounted on a dielectric substrate, and the amplification circuit output on the dielectric substrate. A line conversion substrate 70 on which a line conversion circuit 25 for converting a high-frequency signal of the above into an electromagnetic wave in a waveguide is mounted, and the amplification circuit and the line conversion interposed on the dielectric substrate between the amplification substrate and the line conversion substrate. A line substrate 60 on which a strip line for obtaining matching with a circuit is mounted so as to be fixable on a common housing 10, and the amplification substrate 50 is a line substrate 60 a / 60 b having an arbitrary electrical length or In order to connect the strip line of the amplification substrate to the strip line of 60c, the amplification substrate is configured to be slidable with respect to a fixing member to the casing.

  In the present invention (2), since the amplification substrate 50 is configured to be slidable with respect to the fixing member to the casing, the line substrate 60a / 60b or 60c having an arbitrary electrical length may be sandwiched between the line conversion substrate 70 and the amplification substrate 50. Therefore, it is possible to easily realize an electrical length (line length) that has a required deterrent effect even for out-of-band frequency components existing between the amplifier circuit and the line conversion circuit.

  Further, the high frequency circuit of the present invention (3) is a line which is coupled to a microwave band or millimeter wave band electromagnetic wave in a waveguide and converted into a high frequency signal on a strip line on a dielectric substrate as shown in FIG. A line conversion board 80 on which the conversion circuit 81 is mounted, an amplification board 90 on which an amplification circuit 29 for amplifying a high frequency signal of a strip line is mounted on a dielectric board, and the line conversion board and the amplification board on a dielectric board. A line substrate 60 on which a strip line for obtaining a match between the line conversion circuit and the amplifier circuit is provided so as to be interposed between the line conversion circuit and the amplifier circuit so that the line substrate 60 can be fixed on a common housing. In order to connect the strip line of the amplification substrate to the strip line of the line substrate 60a / 60b or 60c having an electrical length, the amplification substrate is configured to be slidable with respect to a fixing member to the casing. Than is.

  In the present invention (3), since the amplification substrate 90 is configured to be slidable with respect to the fixing member to the casing, the line substrate 60a / 60b or 60c having an arbitrary electrical length can be sandwiched between the line conversion substrate 80 and the circuit board. Therefore, it is possible to easily realize an electrical length that has a required deterrent effect even for out-of-band frequency components existing between the amplifier circuit and the line conversion circuit.

  In the present invention (4), in the above-mentioned present inventions (1) to (3), the high-frequency circuit is constituted by a microstrip line having a microstrip line on the front surface and a ground conductor on the back surface with the dielectric substrate interposed therebetween. It is what.

  As described above, according to the present invention, the electrical length between the signal source circuit and the load circuit can be easily changed, so that the impedance matching within the use band is not impaired and the connection impedance of the out-of-band frequency is also provided. Therefore, it is possible to easily adjust without redesigning or reworking the circuit, and thus the burden of designing and mounting the high frequency circuit can be greatly reduced.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings.

  FIG. 1 is a diagram for explaining the high-frequency circuit according to the first embodiment. As described in FIG. 4, the output of the amplifier circuit is supplied from a microstrip line to a line conversion circuit for converting electromagnetic waves in a waveguide. The high frequency circuit of the part is shown. FIG. 1A is a mounting plan view of a high-frequency circuit, and FIG. 1B is a cross-sectional view taken along line a-a ′ of the circuit.

  In the figure, reference numeral 50 denotes an amplifier substrate (corresponding to the amplification substrate of the present invention) on which a high frequency signal in the microwave band or millimeter wave band is mounted on the dielectric substrate 21, 24 is an amplifier, and 70 is dielectric. An antenna substrate (corresponding to the line conversion substrate of the present invention) on which a line conversion circuit for converting a high-frequency signal output from the amplifier circuit into an electromagnetic wave in the waveguide 11 is mounted on the body substrate 21, 25 is a line conversion electrode (antenna), 60 is a line substrate on which a microstrip line 22 is mounted on the dielectric substrate 21 between the amplifier substrate 50 and the antenna substrate 70 to obtain matching between the amplifier 24 and the line conversion electrode 25; It is a connection member (gold foil, copper foil, bonding wire, etc.) for connecting between strip lines.

  With respect to the line substrate 60, the microstrip line 22 having various electrical lengths can be easily handled in advance so as to easily cope with various electrical lengths that may be necessary for the microstrip line 22 connecting the amplifier 24 and the line conversion electrode 25. A plurality of types of line substrates 60a to 60c and the like are prepared. Reference numeral 17 denotes a screw hole for attaching the line substrates 60a to 60c of various sizes to predetermined positions of the housing 10, and is provided at the same position from the right end of each of the substrates 60a to 60c. As a result, the line substrates 60a to 60c can be connected to the antenna substrate 70 without a gap, and the microstrip line 22 having an electrical length corresponding to the width of each substrate can be provided. The characteristic impedance of the microstrip line 22 at the operating frequency is 50Ω.

  On the other hand, the amplifier substrate 50 on which the amplifier 24 is mounted can be connected to the microstrip line 22 of the amplifier substrate 50 without a gap with respect to the microstrip line 22 of the line substrate 60a / 60b or 60c having an arbitrary electrical length. The cutout grooves 51a and 51b are configured so that the amplifier board 50 is slidable with respect to the fixing screw 15 to the housing 10. Therefore, the amplifier 24 and the line conversion electrode 25 can be easily and surely connected by the microstrip line 22 having a substantially arbitrary electric length.

  FIG. 2 is a diagram for explaining a high-frequency circuit according to the second embodiment, and shows a case where a high-frequency circuit board portion related to an amplifier board is supported by a metal carrier. 2A is a mounting plan view thereof, and FIG. 2B is a cross-sectional view of the amplifier substrate 50 'taken along the line b-b'.

  In the figure, the amplifier board 50 'in this example has a structure in which the entire amplification circuit portion mounted on the dielectric substrate 21 is closely attached to and fixed to a substrate carrier 53 made of aluminum, brass, or the like. Strength and grounding characteristics are increased. 22 is a strip line on the surface, and 23 is a ground conductor on the back of the substrate. Instead of providing the ground conductor 23, the substrate carrier 53 may be used as the ground conductor.

  Further, notches 51 a and 51 b are provided on both sides of the substrate carrier 53 so that the entire substrate carrier 53 can slide freely with respect to the housing 10. The four screws 15 are screwed into the screw holes 11a and 11b of the housing 10 through the grooves 51a and 51b, and the amplifier board 50 'is adhered and fixed to the housing 10 at a required position.

  Although not shown, the circuit boards 53a to 60c of various electrical lengths are also provided with a substrate carrier 53, like the amplifier board 50 '.

  FIG. 3 is a diagram for explaining a high-frequency circuit according to the third embodiment, showing a high-frequency circuit in a portion where a high-frequency signal on a microstrip line obtained by coupling to an electromagnetic wave in a waveguide is amplified by a high-frequency amplifier circuit. Yes. FIG. 3 is a mounting plan view of the high-frequency circuit.

  In the figure, reference numeral 80 denotes a line conversion substrate on which a line conversion circuit that is coupled to a microwave band or millimeter wave band electromagnetic wave in the waveguide 11 and converts it to a high frequency signal on the strip line 22 is mounted on the dielectric substrate 21; 81 is the line conversion electrode (antenna), 90 is an amplifier board (corresponding to the amplification board of the present invention) on which an amplifying circuit for amplifying the high frequency signal of the strip line 22 is mounted on the dielectric substrate 21, 29 is the amplifier, 60 Is a line substrate on which a microstrip line 22 for obtaining matching between the line conversion electrode 81 and the amplifier 29 is mounted on the dielectric substrate 21 between the line conversion substrate 80 and the amplifier substrate 90. As for the line substrate 60, as described with reference to FIG. 1, a plurality of types of line substrates 60a to 60c on which the microstrip lines 22 having various electrical lengths are mounted in advance.

  On the other hand, the amplifier substrate 90 on which the amplifier 29 is mounted can be connected to the microstrip line 22 of the amplifier substrate 90 without a gap with respect to the microstrip line 22 of the line substrate 60a / 60b or 60c having an arbitrary electrical length. The cutout grooves 51a and 51b are configured to allow the amplifier board 90 to slide with respect to the fixing screw 15 to the housing 10. Accordingly, the amplifier 29 and the line conversion electrode 81 can be easily and reliably connected by the microstrip line 22 having a substantially arbitrary electric length.

  In each of the above-described embodiments, an example of a simple line substrate 60 on which only the microstrip line 22 having various electrical lengths is mounted is shown, but the present invention is not limited to this. You may add an isolator circuit, a filter circuit, etc. as needed.

  Moreover, although the application example to the microstrip line of the present invention has been described in the above embodiment, the present invention is not limited to this. The present invention is also applicable to various other striplines such as a coplaner stripline.

  Moreover, although several embodiment suitable for the said invention was described, it cannot be overemphasized that the structure of each part, control, a process, and these combination can be variously changed within the range which does not deviate from this invention. .

It is a figure explaining the high frequency circuit by a 1st embodiment. It is a figure explaining the high frequency circuit by a 2nd embodiment. It is a figure explaining the high frequency circuit by a 3rd embodiment. It is a figure (1) explaining a prior art. It is a figure (2) explaining a prior art.

Explanation of symbols

10 Housing 11 Waveguide 12 Waveguide Opening 15 Screw 17 Screw Hole 21 Dielectric Substrate 22 Microstrip Line 23 Ground Conductor 24 Amplifier (Amplifier)
25 Line conversion electrode (load)
26 connecting member 27 isolator 28 terminator 29 amplifier 30, 50, 50 'amplifier substrate (amplification substrate)
51 Notch groove 53 Substrate carrier 60 Line substrate 70 Antenna substrate 80 Line conversion substrate (antenna substrate)
81 Line conversion electrode 90 Amplifier board (amplification board)

Claims (4)

An amplifying board having an amplifying circuit for amplifying a microwave band or a millimeter wave band high-frequency signal mounted on a dielectric board, and a load circuit for supplying a high-frequency signal of the amplifying circuit output on the dielectric board. A load board and a line board on which a strip line is mounted on a dielectric substrate between the amplification board and the load board for obtaining matching between the amplification circuit and the load circuit, Prepare to fix on the body,
The amplification board is configured to be slidable with respect to a fixing member to the casing so as to connect the strip line of the amplification board to the strip line of the line board having an arbitrary electrical length. A featured high-frequency circuit. An amplification substrate having an amplification circuit for amplifying microwave band and millimeter wave band high frequency signals mounted on a dielectric substrate, and converting the high frequency signal output from the amplification circuit to an electromagnetic wave in a waveguide on the dielectric substrate. A line conversion board on which a line conversion circuit is mounted, and a strip line for obtaining matching between the amplification circuit and the line conversion circuit are mounted on a dielectric substrate between the amplification board and the line conversion board. With the line substrate that can be fixed on a common housing,
The amplification board is configured to be slidable with respect to a fixing member to the casing so as to connect the strip line of the amplification board to the strip line of the line board having an arbitrary electrical length. A featured high-frequency circuit. A line conversion board on which a line conversion circuit that converts microwave waves and millimeter wave band electromagnetic waves in a waveguide into a high frequency signal on a strip line is mounted on a dielectric board, and a strip line on the dielectric board. An amplifying substrate on which an amplifying circuit for amplifying a high-frequency signal is mounted, and a strip for interposing between the line converting substrate and the amplifying substrate on a dielectric substrate to obtain matching between the line converting circuit and the amplifying circuit The track board on which the track is mounted is provided so as to be fixed on a common housing,
The amplification board is configured to be slidable with respect to a fixing member to the casing so as to connect the strip line of the amplification board to the strip line of the line board having an arbitrary electrical length. A featured high-frequency circuit. The high-frequency circuit is configured by a microstrip line that includes a microstrip line on the front surface and a ground conductor on the back surface with a dielectric substrate interposed therebetween. High frequency circuit.

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