CN2106446U

CN2106446U - Wave guide type transistor power amplifier

Info

Publication number: CN2106446U
Application number: CN 91225422
Authority: CN
Inventors: 苏凯雄; 林金清
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 1991-09-18
Filing date: 1991-09-18
Publication date: 1992-06-03

Abstract

The utility model relates to a waveguide type amplifier for transistor power. By means of an input waveguide, input matching fins and grids of a field effect transistor, an input circuit is formed; an output circuit is formed by an output waveguide, output matching fins and drain electrodes of the field effect transistor; a band pass filtering circuit is formed by a coupled waveguide cavity, a coupled matching fin and the field effect transistor; an offset feed circuit of the direct current of the field effect transistor is formed by a offset input hole of the direct current, high resistance offset wires and a high frequency bypass capacitor. Meanwhile, the selections of the optimal dimension of each component are utilized, which can raise the gain, can spread a frequency band, can increase output power, can facilitate debugging and can ensure the stability of performances under different working levels.

Description

Wave guide type transistor power amplifier

The present invention relates to the waveguide type transistor power amplifier (being waveguide type field-effect transistor or bipolar transistor power amplifier) that a kind of microwave regime, particularly superhigh frequency band and millimere-wave band are used hereinafter to be referred as WTPA.

The microwave power amplifier that is applied in superhigh frequency band and millimere-wave band in the prior art mainly contains two types: a kind of is the early stage microwave tube power-like amplifier of using (for example travelling wave tube, klystron, crossed-field amplifier etc.).This class microwave power amplifier has advantages such as gain is high, power output is big, but also exists volume little, the manufacturing process complexity, and the operating voltage height, auxiliary equipment is huge, defectives such as working life weak point.Another kind of is the microstrip type fet power amplifier that occurs in the recent period, this class microwave power amplifier is owing to adopted new type of microwave power field effect device, it is little to have volume, in light weight, characteristics such as the low and long working life of operating voltage, so beginning has little by little replaced the microwave tube power-like amplifier on the microwave low-frequency range, but in the microwave high-frequency section, when that is to say the further raising along with operating frequency, when dimension of microstrip line was enough big with respect to operation wavelength, the mode dispersion phenomenon had appearred in the electromagnetic wave in the microstrip circuit, and the loss of microstrip circuit is increased severely, performance descends rapidly, even cisco unity malfunction.In addition, along with the increase of power output, circuit power consumption increases, and temperature also raises, and variation of temperature changes the electrical quantity of microstrip circuit, thereby influences the stability of microstrip type power amplifier.The appearance of these factors has all limited the application of microstrip type fet power amplifier on high band widely.

The purpose of this invention is to provide a kind of waveguide type transistor power amplifier that can overcome the prior art deficiency, and electrical performance indexes height, simple in structure, with low cost, debugging characteristics such as easy are arranged.

According to purpose of the present invention, the disclosed WTPA of inventor comprises: input waveguide 1, coupled wave guide cavity 2, output waveguide 3, radiator 4, input coupling fin 6,

coupling coupling fin

7,8, output coupling fin 9, field-

effect transistor

10,11, parts such as high resistant offset line 12,13,14,15 and high-frequency bypass capacitor 16,17,18,19 are formed (seeing shown in the accompanying drawing 1).Above-mentioned input waveguide 1, output waveguide 3, coupled wave guide cavity 2 and waveguide radiator 4 are integral structure.Wherein input waveguide 1, output waveguide 3 is folded up and down formula structure with coupled wave guide cavity 2, isolated mutually by 5 of T type waveguide common walls between the three, field-

effect transistor

10 and 11 is installed in two grooves 51,52 of common wall 5, the grid 101,111 of

field effect transistor

10,11 stretches into respectively in input waveguide 1 and the coupled wave guide cavity 2, its drain electrode 102,112 is then stretched into respectively in coupled wave guide cavity 2 and the output waveguide 3, and its source electrode 103,113 usefulness screws are fastened in groove 51 and 52.Input coupling fin 6, output coupling fin 9 are contained in respectively on the grid 101 and drain electrode 112 of field effect transistor, and

coupling coupling fin

7,8 is contained in respectively on drain electrode 102 and the grid 112.The root of high resistant offset line 12,13,14,15 1 ends and field effect transistor gate 101,111 drain electrodes 102,112 is connected, and the other end high-frequency bypass capacitor 16,17,18,19 interior with being installed in groove 51,52 is connected with the direct current biasing incoming line that is penetrated by offset hole 53,54,55,56.

The grid 101 of above-mentioned input waveguide 1, input coupling fin 6 and field-effect transistor 10 constitutes input circuit; The drain electrode 112 of above-mentioned output waveguide 3, output coupling fin 9 and field-effect transistor 11 constitutes output loop; Above-mentioned coupled wave guide cavity 2,

coupling coupling fin

7,8, the drain electrode 102 of field-effect transistor 10 and the grid of field-effect transistor 11 111 constitute the bandpass filtering loop; Above-mentioned direct current biasing input hole 53,54,55,56, high resistant offset line 12,13,14,15 and high-frequency bypass capacitor 16,17,18,19 constitute the direct current biasing feed-in circuit of field-effect transistor 10,11.By the position of selecting suitable input waveguide short circuit face and the size of importing coupling fin 6, realize the Broadband Matching of input circuit and information source; By the position of selecting suitable output waveguide 3 short circuit faces and the size of exporting coupling fin 9, realize the Broadband Matching of output loop and load; By selecting the size of suitable coupled wave guide cavity 2, the size of spacing between the

field effect transistor

10,11 and

coupling coupling fin

7,8 makes the bandpass filtering loop that is constituted realize best transmission characteristic in working band; The length by selecting suitable high resistant offset line 12,13,14,15 and the capacity of high-frequency bypass capacitor 16,17,18,19 make direct current biasing feed-in circuit be open-circuit condition to

field effect transistor

10,11 devices on operating frequency.At last,, the source electrode of

field effect transistor

10,11 and the large tracts of land of waveguide radiator are combined closely, guaranteed minimum thermal resistance and maximum dissipation power by holding screw.

Above-mentioned various measures have been expanded frequency band, have simplified debugging, have guaranteed the stability of performance under the different operating level that the present invention compared with prior art has following advantage: 1, simple in structure, with low cost; 2, operating frequency height, frequency bandwidth are big; 3, power gain height, power output are big; 4, easy, the stable performance of debugging; 5, be convenient to be connected with other waveguide elements.

Further describe the present invention below in conjunction with drawings and Examples

Fig. 1 is a structure cutaway view of the present invention, and wherein, Fig. 1 a is a front view, and Fig. 1 b is an end view, and Fig. 1 c is a upward view.

Fig. 2 is the field-effect transistor of Fig. 1 and the structure enlarged drawing of additional coupling fin thereof.

Fig. 3 is an equivalent circuit diagram of the present invention.

Description of drawings is as follows: 1-input waveguide, 2-coupled wave guide cavity, 3-output waveguide, the 4-radiator, 5-waveguide common wall, 51, the 52-groove, 53,54,55, the 56-input hole of setovering, 6-input coupling fin, 7,8-coupling coupling fin, 9-output coupling fin, 10, the 11-field-effect transistor, 101, the 111-grid, 102,112-drain electrode, 103,113-source electrode, 12,13,14,15-high resistant offset line, 16,17,18, the 19-high-frequency bypass capacitor.

Waveguide-radiator body and input, output and coupling coupling fin as embodiment are selected good electric conductor for use, as the silver-plated material of copper, field-

effect transistor

10 and 11 adopts MGF2116(GP=7dB respectively, P1dB=0.4W) with MGF2148(GP=6dB, P1dB=1.5W)

Present embodiment is used in the 8 gigahertz band terrestrial microwave trunking traffic stations as emission power amplifier usefulness, and it is as follows to record its typical electrical performance characteristics:

Working frequency range: 8GHZ

Frequency bandwidth: 800MHZ

Power output: 1.7W

Power gain: 14dB ± 1dB

Input vswr:＜1.3

Output standing-wave ratio:＜1.3

Claims

1, a kind of waveguide type transistor power amplifier, comprise input waveguide, output waveguide, the waveguide radiator, the waveguide common wall, field-effect transistor, it is characterized in that it also comprises coupled wave guide cavity (2), input coupling fin (6), coupling coupling fin (7), (8), output coupling fin (9), field-effect transistor (10), (11), high resistant offset line (12), (13), (14), (15), high-frequency bypass capacitor (16), (17), (18), (19), above-mentioned input waveguide (1), output waveguide (3), coupled wave guide cavity (2), waveguide radiator (4) is integral structure, input waveguide (1) wherein, output waveguide (3), be folded up and down formula structure with coupled wave guide cavity (2), isolated mutually by T type waveguide common wall (5) institute between the three, field-effect transistor (10) and (11) are installed in two grooves (51) of common wall (5), (52) in, field-effect transistor (10), (11) grid (101), (111) stretch into respectively in input waveguide (1) and the coupled waveguide (2), and its drain electrode (102), (112) then stretch in coupled wave guide cavity (2) and the output waveguide (3) its source electrode (103) respectively, (113) be fastened in groove (51) and (52).Input coupling fin (6), output coupling fin (9) is contained in respectively on the grid (101) and drain electrode (112) of field-effect transistor, coupling coupling fin (7), (8) be contained in respectively on drain electrode (102) and the grid (111), high resistant offset line (12), (13), (14), the grid (101) of an end (15) and field effect transistor, (111) and the drain electrode (102), (112) root connects, the other end be installed in groove (51), (52) Nei high-frequency bypass capacitor (16), (17), (18), (19) with by offset hole (53), (54), (55), (56) the direct current biasing incoming line that penetrates is connected.