CN109975856B - A multi-beam microwave source based on multiplexer - Google Patents

Abstract

The invention relates to the technical field of microwave signal generation, and specifically discloses a multi-beam microwave source based on a multiplexer. A multi-beam microwave source based on a multiplexer. The microwave source includes a first multiplexer, a second multiplexer and a qualitative coupler, wherein several sum output ends of the first multiplexer are connected to the second multiplexer through a microwave amplifier group. The input end of the multiplexer is connected, the output end of the second multiplexer is connected with the input end of the directional coupler, and at the same time, the coupling end of the first multiplexer is connected with the input end of the first multiplexer. The multi-beam microwave source based on a multiplexer of the present invention can output microwave signal sources of multiple frequencies at the same time, and has the characteristics of low cost, high frequency stability, high power flatness, easy maintenance and low phase noise. Adjustable frequency and other advantages.

Description

A multi-beam microwave source based on multiplexer

Technical field

The invention belongs to the technical field of microwave signal generation, and specifically relates to a multi-beam microwave source based on a multiplexer.

Background technique

Comb frequency signal generators have very important applications in electronic circuits, radio frequency and microwave fields. It can be used as a multiple frequency signal source for measurements at different frequency points.

In controlled nuclear fusion experimental research, turbulent disturbances and distributions at different scales inside the plasma determine the confinement and transport of the plasma. Obtaining the relationship between these disturbances at different scales is useful for studying plasma physics and plasma profile safety control. important helping role. Microwave reflection is one of the important diagnostics for measuring plasma turbulence distribution. Its basic principle is to use microwaves to reflect on the electron density cutoff layer inside the plasma. In order to measure parameters such as electron density disturbance and distribution inside the plasma, multiple microwaves with different frequencies need to be emitted into the plasma at the same time. These microwaves with different frequencies are reflected at different electron density cutoff layers and can carry out the internal reflections of the plasma at the same time. The perturbation and distribution information of the cut-off layer, therefore, the comb frequency array signal generator of multiple frequencies is the core of realizing multi-space point measurement. There are currently three main methods of generating comb frequency arrays: the first is the synthesis of multiple independent microwave sources. Since the cost of using multiple independent microwave sources is high, the measurement range is relatively limited, and the practicality is not strong. Currently, only the German ASDEX-U device uses two independent microwave measurement systems, and only two sets of independent microwave measurement systems can be obtained. Simultaneous measurement of space points. The second method is to use a mixer for frequency conversion. Due to the frequency conversion efficiency of the mixer, the high-order signal frequency power is poor and the number of frequency arrays is also small. The third type mainly uses nonlinear devices, such as step diodes or voltage-controlled oscillators (VCO) modulation to generate multiple frequency multiplication signals or modulated signals. However, the intermediate frequency bandwidth of step diodes is usually narrow, and it is also difficult to reach microwave In the frequency band, after frequency doubling, the power consistency at each frequency point is difficult to control.

Contents of the invention

The purpose of the present invention is to provide a multi-beam microwave source based on a multiplexer to solve the problem of high cost of multiple signal sources, low modulation frequency of millimeter wave source, narrow bandwidth, etc. when generating multiple frequency signal arrays in the prior art. limit.

The technical solution of the present invention is as follows: a multi-beam microwave source based on a multiplexer. The microwave source includes a first multiplexer, a second multiplexer and a qualitative coupler, wherein several sum output terminals of the first multiplexer The microwave amplifier group is connected to the input end of the second multiplexer, the output end of the second multiplexer is connected to the input end of the directional coupler, and at the same time, the coupling end of the first multiplexer is connected to the first multiplexer connected to the input terminal.

The first multiplexer and the second multiplexer are both the same microwave band or radio frequency band multiplexers, and their input terminals and output terminals may be different from each other.

The number of output terminals of the first multiplexer and the second multiplexer is determined by the number of comb frequencies that need to be generated, and the filter frequency bandwidth of each output terminal does not overlap or load each other, so that each output Maintain a high degree of isolation between terminals, and its isolation reaches more than 40dB.

The filtering frequency of each output end of the first multiplexer and the second multiplexer has a peaked passband distribution, and the bandwidth is narrow, and the millimeter wave frequency band is usually 50MHz; the first multiplexer The output end of the multiplexer and the second multiplexer can achieve 2 to 32 outputs.

The number of output terminals of the microwave amplifier group matches that of the first multiplexer and is connected one to one; the gain of the microwave amplifier group is greater than that of the first multiplexer and the second multiplexer. Multiplexer loop loss; the gain of the microwave amplifier group is greater than 20dB.

The directional coupler couples the signal synthesized by the second multiplexer to the first multiplexer; the coupling degree of the directional coupler is 10-20dB, and the isolation is greater than 25dB; the working frequency band of the directional coupler Determined by the operating frequency of the multiplexer loop.

A broadband microwave amplifier is provided between the coupling end of the directional coupler and the input end of the first multiplexer, and the broadband microwave amplifier covers the operating frequency points of all channels.

The output end of the directional coupler is connected to the signal output monitoring quantity system through the microwave isolator and the monitoring coupler in sequence, and the output end of the monitoring coupler is connected to the output antenna for transmitting signals to the target to be measured.

The isolator can prevent microwaves from being reflected by peripheral systems and affecting the multiplexer loop, and requires an isolation degree greater than 20dB.

The monitoring coupler is used to couple a signal from the directional coupler output signal to the signal output measurement system to obtain the microwave signal output frequency and power in real time. The coupling degree of the monitoring coupler is 20dB, and the isolation degree is greater than 25dB. Its operation The frequency band is the same as the directional coupler.

The significant effect of the present invention is that: the multi-beam microwave source based on a multiplexer of the present invention can output microwave signal sources of multiple frequencies at the same time, and has low cost, high frequency stability, high power flatness, It has the advantages of easy maintenance, low phase noise, and adjustable frequency.

Description of drawings

Figure 1 is a schematic structural diagram of a multi-beam microwave source based on a multiplexer according to the present invention;

In the picture: 1. First multiplexer; 2. Microwave amplifier group; 3. Second multiplexer; 4. Directional coupler; 5. Microwave isolator; 6. Monitoring coupler; 7. Signal output monitoring system ; 8. Output antenna.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, a multi-beam microwave source based on a multiplexer includes a first multiplexer 1, a microwave amplifier group 2, a second multiplexer 3 and a qualitative coupler 4, where the first multiplexer Several sum output terminals of 1 are connected to the input terminal of the second multiplexer 3 through the microwave amplifier group 2, and the output terminal of the second multiplexer 2 is connected to the input terminal of the directional coupler 4. At the same time, the first multiplexer The coupling end of the device 1 is connected to the input end of the first multiplexer 1; the output end of the directional coupler 4 is connected to the signal output monitoring system 7 through the microwave isolator 5 and the monitoring coupler 6 in turn, and the monitoring coupler The output end of 6 is connected to the output antenna 8 for transmitting signals to the target to be measured; the first multiplexer 1 and the second multiplexer 3 are the same microwave band or radio frequency band multiplexers, and their input end and output The terminals can be different from each other; the number of output terminals of the first multiplexer 1 and the second multiplexer 3 is determined by the number of comb frequencies that need to be generated. Generally, 2 to 32 outputs can be achieved, and the filter frequency bandwidth of each output terminal is mutually exclusive. There is no superposition or mutual loading, so that each output end is highly isolated, and the isolation degree reaches more than 40dB; the filtering frequency of each output end of the first multiplexer 1 and the second multiplexer 3 is a peaked pass Band distribution, and the bandwidth is narrow, the millimeter wave frequency band is usually about 50MHz; the microwave amplifier group 2 is determined according to the number of output terminals of the first multiplexer 1, and is connected to the output terminals of the first multiplexer 1 in a one-to-one correspondence. The gain of microwave amplifier group 2 is greater than the loss of the entire multiplexer loop. Usually the gain of microwave amplifier group 2 is greater than 20dB; if the multiplexer loop loss composed of the first multiplexer 1 and the second multiplexer 3 is large, A broadband microwave amplifier can be added between the coupling end of the directional coupler 4 and the input end of the first multiplexer 1, which covers the operating frequency points of all channels; the directional coupler 4 can couple the signal synthesized by the second multiplexer 3 Give the first multiplexer 1 and form a multiplexer loop. The coupling degree of the directional coupler 4 is 10-20dB and the isolation is greater than 25dB. Its operating frequency band is determined by the operating frequency of the multiplexer loop; in the microwave amplifier When the gain of 2 is slightly less than or close to the total insertion loss of the multiplexer loop, the power of the coupling end of the directional coupler 4 can be increased to ensure that the microwave amplifier group 2 can drive the multiplexer loop and generate signal output; the isolator 5 can To prevent microwaves from being reflected by peripheral systems and affecting the multiplexer loop, isolation is usually required to be greater than 20dB; the monitoring coupler 6 is used to couple a signal from the output signal of the directional coupler 4 to the signal output measurement system 7 to The microwave signal output frequency and power are obtained in real time. The coupling degree of monitoring coupler 6 is 20dB, the isolation degree is greater than 25dB, and its working frequency band is the same as directional coupler 4.

Claims (8)

1. A multi-beam microwave source based on a multiplexer, characterized in that: the microwave source includes a first multiplexer (1), a second multiplexer (3) and a directional coupler (4), wherein the first Several output terminals of the multiplexer (1) are connected to the input terminals of the second multiplexer (3) through the microwave amplifier group (2), and the output terminals of the second multiplexer (2) are connected to the directional coupler (4) At the same time, the coupling end of the first multiplexer (1) is connected to the input end of the first multiplexer (1); the microwave amplifier group (2) and the first multiplexer The number of output terminals of (1) matches and is connected one by one; the gain of the microwave amplifier group (2) is greater than the multiplexer composed of the first multiplexer (1) and the second multiplexer (3). The circuit loss of the device; the gain of the microwave amplifier group (2) is greater than 20dB; the output end of the directional coupler (4) passes through the microwave isolator (5), the monitoring coupler (6) and the signal output monitoring system ( 7), and connect the output end of the monitoring coupler (6) to the output antenna (8) for transmitting signals to the target to be measured. 2. A multi-beam microwave source based on a multiplexer according to claim 1, characterized in that: the first multiplexer (1) and the second multiplexer (3) are both The input terminals and output terminals of the same microwave band or radio frequency band multiplexer can be different from each other. 3. A multi-beam microwave source based on a multiplexer according to claim 1, characterized in that: the output ends of the first multiplexer (1) and the second multiplexer (3) The number is determined by the number of comb frequencies that need to be generated, and the filter frequency bandwidths of each output end do not overlap or load each other, so that each output end maintains a high degree of isolation, and its isolation reaches more than 40dB. 4. A multi-beam microwave source based on a multiplexer according to claim 1, characterized in that: each of the first multiplexer (1) and the second multiplexer (3) The filter frequency of each output terminal is a peaked passband distribution, and the bandwidth is narrow, and the millimeter wave frequency band is usually 50MHz; the output terminals of the first multiplexer (1) and the second multiplexer (3) Can achieve 2~32 outputs. 5. A multi-beam microwave source based on a multiplexer according to claim 1, characterized in that: the directional coupler (4) couples the signal synthesized by the second multiplexer (3) to the first Multiplexer (1); the coupling degree of the directional coupler (4) is 10~20dB and the isolation degree is greater than 25dB; the working frequency band of the directional coupler (4) is determined by the working frequency of the multiplexer loop . 6. A multi-beam microwave source based on a multiplexer according to claim 1, characterized in that: the coupling end of the directional coupler (4) and the input of the first multiplexer (1) A broadband microwave amplifier is provided between the terminals, and the broadband microwave amplifier covers the working frequency points of all channels. 7. A multi-beam microwave source based on a multiplexer according to claim 1, characterized in that the isolator (5) can prevent microwaves from being reflected by peripheral systems and affecting the multiplexer loop. It requires isolation greater than 20dB. 8. A multi-beam microwave source based on a multiplexer according to claim 1, characterized in that: the monitoring coupler (6) is used to couple out a signal from the output signal of the directional coupler (4) to the signal output measurement system (7) to obtain the microwave signal output frequency and power in real time. The coupling degree of the monitoring coupler (6) is 20dB, the isolation is greater than 25dB, and its working frequency band is the same as the directional coupler (4).