Microwave radiation generator

Abstract

This utility model pertains to microwave technology, specifically to the coherent power combining of two magnetrons to increase output power and operating time in combining mode, independent of temperature-induced frequency drift of the magnetrons. It can be used primarily in radar transmitters, microwave power systems for charged particle accelerators, and industrial microwave heating systems. To increase the efficiency and operating time of the microwave generator in coherent power combining mode, the quadrature waveguide bridge is designed as an asymmetrical structure, and its second output is connected to a rectangular waveguide containing a matched load and a thin inductive diaphragm.This creates the required impedance (reactive resistance) in the waveguide, leading to feedback between the magnetrons, which is necessary for coherent power combining of the two magnetrons. This improves the generator's functionality: the magnetrons' operating time in coherent power combining mode is unlimited, frequency adjustment during operation, including compensation for temperature-induced frequency drift, is not required, and any necessary interruptions in operation do not change the combining mode.

Description

[0001] The utility model relates to ultra-high frequency (UHF) technology, specifically to the coherent addition of the powers of two magnetrons in order to increase the output power and operating time in the addition mode, independent of the temperature drift of the magnetron frequency, and can be used primarily in transmitting devices of radar stations (RLS), ultra-high frequency power supply systems for charged particle accelerators and industrial microwave heating systems.

[0002] Among the existing technology, the closest to the claimed technical solution for coherent addition of the powers of two magnetrons is a microwave radiation generator module (patent for utility model No. 208358, published on 12 / 15 / 2021, prototype), the block diagram of which is shown in Fig. 1.

[0003] The quadrature waveguide bridge of the utility model prototype shown in Fig. 1 is a symmetrical 3-dB bridge, calculated and experimentally manufactured in such a way that the S-parameters characterizing the quadrature waveguide bridge shown in Fig. 2 have the following values: (S1,3 = S2,4) are equal to (S1,4 = S2,3) at one point at the frequency f0 and with an increase or decrease in the generation frequency of the magnetrons, the values ​​of the S-parameters (S1,3 = S2,4) and (S1,4 = S2,3) diverge (change). That is, there is a frequency dependence of the above S-parameters on the frequency. The numbers at the S-parameters 1,2,3,4 denote respectively input 1, input 2, output 3, output 4 of the quadrature symmetrical waveguide bridge.

[0004] In this regard, coherent addition of the powers of two magnetrons in a quadrature waveguide bridge is possible only at one point f0, since as the magnetrons operate, heating occurs, which leads to a change in the frequency of the magnetrons (temperature drift) and a change in the values ​​of the S-parameters indicated above.

[0005] The operating time of magnetrons in the coherent power addition mode is only a few minutes, since as the magnetron housings heat up, their generation frequency and S-parameter values ​​change, and the addition stops.

[0006] To increase the operating time of magnetrons in the coherent power addition mode, thermal stabilization (temperature constancy on the magnetron housings) is necessary, which is practically impossible to achieve in reality.

[0007] The technical problem solved by the utility model is to increase the efficiency and operating time of a microwave radiation generator device in the mode of coherent addition of the powers of two magnetrons.

[0008] This task is achieved by the fact that in a microwave generator device containing two magnetrons, a tunable phase shifter, a quadrature waveguide bridge as a summator, one output of which is the output of energy to the load, the quadrature waveguide bridge is made asymmetrical, and a rectangular waveguide is connected to its second output, into which a matched load and a thin inductive diaphragm are built.

[0009] As a result, the required impedance (reactive resistance) value is created in the waveguide, leading to the formation of feedback between the magnetrons, which is necessary for the coherent addition of the powers of the two magnetrons.

[0010] In FIG. Figure 1 shows a block diagram of the prototype.

[0011] Fig. 2 shows the parameters characterizing the symmetrical quadrature waveguide bridge.

[0012] Fig. 3 shows a block diagram of the proposed microwave radiation generator device.

[0013] Fig. 4 shows the S-parameters of an asymmetric quadrature waveguide bridge.

[0014] The following designations are shown in Fig. 3: 1 - magnetron; 2 - modulator; 3 - magnetron; 4 - modulator; 5 - tunable phase shifter; 6 - quadrature waveguide bridge; 7 - energy output to the load (antenna); 8 - rectangular waveguide; 9 - matched load; 10 - thin inductive diaphragm.

[0015] Magnetron 1 with modulator 2 is connected to one of the inputs - input A of quadrature waveguide bridge 6, between magnetron 3 with modulator 4 and the other input - input B of quadrature waveguide bridge 6, a tunable phase shifter 5 is connected. To one output - output C of quadrature waveguide bridge 6, the energy output to the load (antenna) 7 is connected, to the other output - output D of quadrature waveguide bridge 6, a rectangular waveguide 8 with a built-in matched load 9 and a thin inductive diaphragm 10 is connected.

[0016] The device operates as follows. The modulating pulse generated by modulator 2 is fed to magnetron 1, activating it. The microwave energy generated by magnetron 1 is fed to input A of quadrature waveguide bridge 6. The modulating pulse generated by modulator 4 is fed to magnetron 3, activating it. The microwave energy generated by magnetron 3 is fed to input B of asymmetrical quadrature bridge 6, passing through tunable phase shifter 5, with the help of which phase synchronization and synchronous addition in the quadrature waveguide bridge of the powers of two magnetrons are achieved, the power of which approximately 90% is fed to the useful load (antenna) 7 from output C, and approximately 10% of the power is fed to output D to the connected rectangular waveguide 8, into which a matched load 9 and a thin inductive diaphragm 10 are built in, with the help of which the required value of impedance (reactive resistance) is created, which is an inhomogeneity.The power arriving at the output D of the asymmetrical quadrature waveguide bridge 6 is reflected from the inhomogeneity and arrives at the input A and input B of the asymmetrical quadrature waveguide bridge 6. This process leads to the creation of feedback between the magnetrons, which is necessary for the coherent addition of the powers of the two magnetrons.

[0017] The asymmetric quadrature waveguide bridge 6, the block diagram of which is shown in Fig. 3, is calculated and designed in such a way that the S-parameters (S A,C = S B,D ) and (S A,D = S B,C ), shown in Fig. 4, have different values ​​that are independent of frequency over a wide range. The letters A, B, C, D for the S-parameters denote, respectively, input A, input B, output C, output D of the quadrature asymmetric waveguide bridge 6.

[0018] The impedance value is selected experimentally by symmetrically overlapping the rectangular cross-section of a thin inductive diaphragm on its wide wall on both sides. The experimentally selected overlap values ​​for the wide wall of the diaphragm are 40–45% of its length. The thickness of the thin inductive diaphragm is much smaller than the wavelength in the waveguide. In reality, the ratio of the thickness of the thin inductive diaphragm to the wavelength in the waveguide is 0.02.

[0019] As a result, the generator's functionality has been improved: the operating time of the magnetrons in the coherent power addition mode is not limited by time, frequency adjustment of the device during operation, including compensation for temperature frequency drift, is not required, and possible necessary interruptions in operation do not lead to changes in the addition modes.

[0020] The declared device has the following advantages:

[0021] When the device operates in the mode of coherent addition of the powers of two magnetrons, the power value in the payload (antenna) is achieved to be at least 0.9 of the sum of the powers of the magnetrons;

[0022] When replacing magnetrons, it is much easier to set up the coherent power addition mode of two magnetrons, since the necessary feedback between the magnetrons has already been selected;

[0023] The operation of the device in the mode of coherent addition of the powers of two magnetrons with the existing real temperature drift of the magnetron frequency does not require thermal stabilization, which significantly simplifies and reduces the cost of the device design.

Claims

A microwave generator device containing two magnetrons, a tunable phase shifter, a quadrature waveguide bridge as a summator, one output of which is the output of energy to a load, characterized in that the quadrature waveguide bridge is made asymmetrical and a rectangular waveguide is connected to its second output, into which a matched load and an inductive diaphragm are built in, the ratio of the thickness of which to the wavelength in the waveguide is 0.02.

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