JP4703391B2 - High frequency power amplifier - Google Patents

Description

  The present invention relates to a high frequency power amplifier used for transmitting a high frequency signal such as a microwave.

  In a microwave power amplifier used in a transmitter of a radar apparatus, a transmission signal is distributed to a plurality of systems by a distributor, and each system signal is amplified by a unit amplifier and then synthesized by a combiner. Output power is obtained (see, for example, Non-Patent Document 1). For this reason, a plurality of system unit amplifiers are arranged close to each other between the distributor and the combiner. In this case, each unit amplifier is accommodated in a shield case because a shield is necessary to suppress unwanted propagation modes and prevent mutual interference. As a result, the case of each unit amplifier is equipped with a connector for connecting a coaxial cable at the input / output end of the signal, and the distributor and the combiner are connected by a coaxial cable.

By the way, with the recent improvement in semiconductor integrated circuit mounting technology, the distributor, unit amplifier, and synthesizer are all integrated into a microstrip line, and the entire device is downsized. Here, the unit amplifiers are individually housed in the shield case as described above, and transmission by a coaxial cable is inevitable for signal input and output. For this reason, the space efficiency is reduced by the routing of the cable. In addition, since it is necessary to convert the microstrip line output into a coaxial connector once, a large power loss occurs in this portion.
Published by The Institute of Electronics, Information and Communication Engineers, Corona Publishing Co., Ltd., “Revised Radar Technology”, page 165

  As described above, in the conventional distribution / synthesis type high frequency power amplifier, a plurality of system unit amplifiers are individually housed in a shield case, and transmission and reception of signals using a coaxial cable is unavoidable. The space efficiency is reduced by the routing, and the microstrip line output needs to be converted into a coaxial connector once. Therefore, there is a problem in that a large power loss occurs in this portion.

  The present invention has been made to solve the above-described problems, and enables a distributor, a unit amplifier, and a combiner to be directly connected without using a coaxial cable while securing a shield for each unit amplifier. Thus, an object of the present invention is to provide a high-frequency power amplifier that can simultaneously reduce the size of the device and reduce power loss.

  In order to solve the above problems, a high-frequency power amplifier according to the present invention distributes a high-frequency signal to a plurality of systems, a distributor formed by forming a distribution output terminal of each system with a microstrip line, and the plurality of systems A plurality of unit amplifiers, each of which is provided with an input terminal and an output terminal formed of a microstrip line, amplifies a high frequency signal supplied to the input terminal and outputs the amplified signal from the output terminal; A synthesizer that has a terminal formed of a microstrip line, synthesizes and outputs a high-frequency signal supplied to the input terminal, a distributor, a plurality of unit amplifiers, a base plate on which a synthesizer is mounted and fixed, and the distributor The distributor is configured to input the high-frequency signals distributed by the amplifier to the plurality of unit amplifiers to amplify the power, and to synthesize the amplified signals of each system by the combiner, A terminal junction means for joining corresponding terminals of each of the level amplifier and the combiner, and a block made of a shielding material on the output side of the distributor and the input side of the combiner for the unit amplifier, Shielding means for covering a side surface and an upper surface between the distributor and the combiner with a plate made of a shielding material and a cover, respectively, is provided.

  As described above, in the present invention, the terminals of the distributor, unit amplifier, and synthesizer are formed by microstrip lines, and the terminals are joined by copper foil or the like, so that the distributor, unit amplifier, and synthesizer are coaxially connected. By directly connecting without using a cable and covering the entire unit amplifier with a shielding material after the joining process, the shield of each unit amplifier is secured.

  According to the present invention, it is possible to directly connect a distributor, a unit amplifier, and a combiner without using a coaxial cable while securing a shield of each unit amplifier, thereby reducing the size of the apparatus and reducing power loss. It is possible to provide a high-frequency power amplifier that can simultaneously realize reduction.

  Prior to describing the embodiment of the present invention, the structure of a microwave power amplifier employed in a conventional radar apparatus will be briefly described with reference to FIG.

  2A is a top view and FIG. 2B is a wave side view. Reference numeral 11 denotes a base plate that functions as a heat sink. On the base plate 11, a two-system distributor 12, two unit amplifiers 13a and 13b, and a two-system synthesizer 14 are mounted and fixed. The unit amplifiers 13a and 13b of each system are both housed in a shield case and covered with a shield cover in order to suppress unnecessary propagation modes and prevent mutual interference. The signal input / output terminals are each equipped with a coaxial connector, and the coaxial connectors provided at the signal output terminal of the distributor 12 and the signal input terminals of the combiner 14 are connected by a coaxial cable.

  That is, in the power amplifier having the above structure, the input microwave signal is distributed to the two systems by the distributor 12, supplied to the unit amplifiers 13a and 13b via the coaxial cables, and amplified in parallel, and the amplified output thereof. Is sent to the combiner 14 by a coaxial cable. In this structure, as described above, the unit amplifiers 13a and 13b are individually accommodated in the shield case, and the coaxial cable is used for signal input / output, so that the space efficiency is lowered by the cable routing. Even if the distributor 12, the unit amplifiers 13a and 13b, and the combiner 14 all have an integrated circuit structure using a microstrip line, it is necessary to convert the microstrip line output into a coaxial connector. There is a great power loss.

  An embodiment of the present invention that solves the above problem will be described below with reference to FIG.

  FIG. 1 shows a structure in the case where the present invention is applied to the above-described microwave power amplifier as one embodiment of the present invention, where (a) shows a top view and (b) shows a side view.

  In FIG. 1, reference numeral 21 denotes a base plate that functions as a heat sink. Unit amplifiers (unshielded substrates themselves) 23 a and 23 b are fixed side by side at the center on the base plate 21. The two-system synthesizer 24 is fixed.

  On the distribution output side of the distributor 22, an edge 221 is formed integrally with the main body on the joint side with the base plate 21, and output from an internal circuit board (not shown) as a two-system output end by a microstrip line. Terminals 222 a and 222 b are formed on the edge 221. Similarly, on the synthesis input side of the synthesizer 24, an edge 241 is integrally formed with the main body on the side joined to the base plate 21, and a microstrip is formed from an internal circuit board (not shown) as a two-system input end. Input terminals 242a and 242b by lines are formed on the edge 241.

  On the other hand, in the unit amplifiers 23a and 23b, the microstrip line input terminals 23a1 and 242b are opposed to the microstrip line output terminals 222a and 222b of the distributor 22 and the microstrip line input terminals 242a and 242b of the combiner 24, respectively. , 23b1 and output terminals 23a2 and 23b2. Then, by connecting the respective opposing terminals with copper foil, transmission by a microstrip line between the distributor, the unit amplifier, and the combiner is made possible.

  The shield of the unit amplifier 23a is realized by the following structure. Since the shield structure of 23b is the same as that of 23a, its description and reference numerals on the drawings are omitted.

  First, a metal material having a shielding effect is used for the base plate 21. On the upper portions of the edge portions 221 and 241 of the distributor 22 and the combiner 24, inverted L-shaped blocks A1 and A2 made of a shielding material are placed. The side surfaces of these blocks A1 and A2 have dimensions that are flush with the end surfaces of the edge portions 221 and 241 of the distributor 22 and the combiner 24, respectively. Further, at the edge formed on the upper side of these blocks A1 and A2, a groove portion is formed in a portion contacting the upper surface of the case of each of the distributor 22 and the combiner 24, and a tube-like conductive material having a shielding effect is formed here. The cushioning materials A3 and A4 are inserted. Although not shown in detail, notches are formed in the blocks A1 and A2 so as not to contact the inter-terminal junctions of the unit amplifier 23a, the distributor 22, and the synthesizer 24 made of copper foil.

  Plates A5 and A6 are mounted on the side surface of the unit amplifier 23a so as to close the space between the distributor 22 and the combiner 24 (between the blocks A1 and A2). At this time, gaps are filled in the joint surfaces of the plates A5 and A6 and the base plate 21 and the joint surfaces of the blocks A1 and A2 with sheet-like conductive cushioning materials A7 and A8, respectively. The blocks A1 and A2 and the plates A5 and A6 have the same upper surface, and a cover A8 made of a shielding material is placed on the upper surface of these members, and the base plate is viewed from above at the main points (six locations in the figure). Screw it to 21.

  According to the above structure, the bottom surface of the unit amplifier 23a is shielded by the base plate 21, its side surface is shielded by the blocks A1, A2 and the plates A5, A6, and its top surface is shielded by the cover A8. Furthermore, since the blocks A1 and A2 are pressed against the upper surfaces of the distributor 22 and the synthesizer 24 by screwing, the conductive cushioning materials A3 and A4 interposed between the blocks A1 and A2 are also brought into close contact with each contact surface, thereby further improving the shielding effect. Can be obtained.

  Therefore, in the high frequency power amplifier having the above configuration, the output terminal of the distributor 22 and the input terminal of the synthesizer 24 are each configured by a microstrip line, and the unit amplifiers 23a and 23b are directly mounted on the base plate (heat sink) 21 while being a substrate. I try to do that. At this time, since the unit amplifiers 23a and 23b are constituted by microstrip lines, they can be directly connected to the output terminals and input terminals of the distributor 22 and the combiner 24 with copper foil or the like. The unit amplifiers 23a and 23b are simultaneously shielded by the blocks A1 and A2, the plates A5 and A6, and the cover A8, including the connecting portion between the distributor 22 and the combiner 24. At this time, the conductive cushioning material A7 is interposed between the blocks A1 and A2 and the plates A5 and A6. Thereby, it is possible to prevent a shield gap from being generated due to a dimensional error between the distributor 22, the combiner 24, and the unit amplifiers 23a and 23b.

  The conductive buffer materials A3, A4, and A7 used in the above embodiment obtain a shielding effect by reflecting radio waves. However, the same effect can be obtained by using a radio wave absorber that absorbs radio waves instead. A shielding effect can be obtained.

  In particular, in the above method, the case of the unit amplifier that has been used conventionally can be eliminated, so that costly parts can be reduced. In addition, as a method of connecting to a distributor or synthesizer, since the microstrip line is joined as it is, there is no need to convert to a coaxial line and wire with a cable as in the past, thereby reducing microwave power loss. And the performance of the device can be improved.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The top view and side view which show the structure of one Embodiment of the high frequency power amplifier based on this invention. The top view and side view which show the structure of the conventional high frequency power amplifier.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Base plate, 12 ... Two system divider | distributor, 13a, 13b ... Unit amplifier, 14 ... Two system synthesizer, 21 ... Base plate, 22 ... Two system divider | distributor, 221 ... Edge, 222a, 222b ... Output terminal, 23a, 23b, unit amplifier, 24, two-line synthesizer, 241, edge, 242a, 242b, input terminal, 23a1, 23b1, input terminal, 23a2, 23b2, output terminal, A1, A2, inverted L-shaped block, A3 A4 ... conductive buffer material (radio wave absorber), A5, A6 ... plate, A7 ... conductive buffer material (radio wave absorber), A8 ... cover.

Claims (3)

A base plate made of shielding material,
A plurality of unit amplifiers that are fixed in the same direction in the center of the base plate, each having input terminals and output terminals formed by microstrip lines on both sides of the power amplification substrate,
The base plate is arranged on the input terminal side of each of the plurality of unit amplifiers, the width of the main body is wider than the arrangement width of the plurality of unit amplifiers, and the edge is integrally formed with the main body on the joint side with the base plate. A plurality of output terminals by microstrip lines from the internal circuit board are formed on the edge so as to face the input terminals of the plurality of unit amplifiers, and a high frequency signal is input and distributed to the plurality of output terminals. A distributor to
The base plate is arranged on the output terminal side of each of the plurality of unit amplifiers, the width of the main body is wider than the arrangement width of the plurality of unit amplifiers, and the edge is integrally formed with the main body on the joint side with the base plate. A plurality of input terminals by microstrip lines from the internal circuit board are formed on the edge so as to face the output terminals of the plurality of unit amplifiers, and a high frequency signal supplied to the plurality of input terminals is synthesized. An output synthesizer;
A terminal junction that joins between a plurality of output terminals of the distributor and input terminals of the plurality of unit amplifiers, and between an output terminal of each of the plurality of unit amplifiers and a plurality of input terminals of the combiner. Means,
Shielding means for shielding the plurality of unit amplifiers;
Comprising
The shielding means includes
It is joined to the upper part of the edge of each of the distributor and the combiner, is formed of a shielding material so that the side surface is flush with the end surface of the edge, and is at least as high as the main body, and First and second blocks in which notches are formed so as not to contact the inter-terminal joints;
The first and second blocks are joined so as to close both sides where the plurality of unit amplifiers are arranged between the distributor and the combiner mounted on the edge, and the first and second blocks First and second plates formed of a shielding material so as to be the same height as the block of
Wherein between the upper surface of the first and second blocks, said first and second plates of the high-frequency power amplifier, characterized in that it comprises a cover with <br/> by shielding material which is bonded to cover the inter-top.   2. The high frequency power amplifier according to claim 1, wherein the shield means interposes a conductive buffer material or a radio wave absorber in the joining of the plates.   The shield means forms an edge portion facing the upper surface of each of the distributor and the combiner in the block, and a conductive buffer material or a radio wave absorber is interposed between the edge portion and the facing surface. The high frequency power amplifier according to claim 1.

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