A rectangular frame-double-rod slow-wave structure

Abstract

The present invention relates to a rectangular frame-double-rod slow-wave structure, which belongs to a traveling wave tube amplifier device. The present invention comprises a rectangular shielding tube 1, a dielectric substrate 2, and a frame-rod slow-wave circuit; the frame-rod slow-wave circuit is a rectangular frame-double-rod slow-wave circuit, which is a pair of symmetrically distributed metal connecting rods connected between adjacent rectangular metal wire frames. The present invention can be directly cut and processed as a whole in the longitudinal and vertical directions using an electric spark wire, and the processing is simple, the integrity is good, the processing accuracy is high, the assembly is simple, and the accuracy is easy to ensure. The present invention uses a strip electron beam with the same electrical parameters to interact with the electromagnetic waves propagating in the slow-wave structure. Compared with the existing frame-rod slow-wave structure, it not only has a wider working frequency band, but also has a higher coupling impedance in the working frequency band, which can further improve the working bandwidth and output power of the traveling wave tube.

Description

Technical Field

[0001] The invention relates to a rectangular frame-double-rod slow-wave structure, belonging to a traveling wave tube amplifier device. Background Art

[0002] As a microwave power amplifier, the traveling wave tube is widely used in the fields of communication, radar, and electronic countermeasures. Compared with solid-state electronic devices, the traveling wave tube has outstanding advantages such as wide bandwidth, high gain and long life.

[0003] Among the components of a traveling wave tube, the slow wave system is a key component that determines its performance. Electromagnetic waves with a phase velocity less than the speed of light propagate in the slow wave structure. When the speed of the electromagnetic wave and the speed of the external electron beam meet the synchronization conditions, the two will interact with each other, and the kinetic energy of the electron beam will be converted into the energy of the electromagnetic wave, thus achieving microwave power amplification.

[0004] Higher operating frequency and greater output power are the two main directions of the current development of traveling wave tubes. The traditional circular helix slow-wave structure has the advantage of flat dispersion, and the traveling wave tube based on this slow-wave structure can achieve an octave bandwidth. However, the coupling impedance of the circular helix is ​​low, which limits the output power. In order to improve the output power of the traveling wave tube, researchers have proposed slow-wave structures such as rectangular helix and rectangular frame-single rod. The rectangular helix has a dispersion characteristic similar to that of the traditional circular helix, but has a larger coupling impedance, while the rectangular frame-single rod slow-wave structure belongs to a double-winding helix slow-wave structure. Under the same structural parameter conditions, the coupling impedance of the rectangular frame-single rod slow-wave structure is significantly improved compared to the rectangular helix.

[0005] Although the coupling impedance of the rectangular frame-single-rod slow-wave structure is much higher than that of the rectangular spiral, the working frequency band of the rectangular frame-single-rod slow-wave structure is relatively small. As the operating frequency of the traveling wave tube increases, the size of the slow-wave structure becomes smaller and smaller, and there are problems such as the difficulty of slow-wave structure processing and low processing accuracy. The reduction in size also makes the channel size of the electron beam smaller, which is not conducive to the passage of large current electron beams. These factors have hindered the development of traveling wave tubes towards high frequency and high power. Summary of the invention

[0006] The purpose of the present invention is to provide a rectangular frame-double-rod slow-wave structure to further improve the operating frequency band and output power of the frame-rod slow-wave structure traveling wave tube.

[0007] A rectangular frame-double-rod slow-wave structure, comprising a rectangular shielding tube 1, a dielectric substrate 2, and a frame-rod slow-wave circuit;

[0008] The frame-rod slow-wave circuit is a rectangular frame-double-rod slow-wave circuit, in which a pair of symmetrically distributed metal connecting rods are connected between adjacent rectangular metal wire frames.

[0009] The pair of metal connecting rods are alternately located on the center connecting line of the long side and the short side of the rectangular metal wire frame.

[0010] The pair of metal connecting rods are alternately located at opposite corners of the rectangular metal wire frame.

[0011] The lengths of the metal connecting rods between adjacent rectangular metal wire frames are all equal, or the lengths gradually increase, or the lengths gradually decrease, or the lengths vary randomly.

[0012] The present invention can be directly processed by electric spark wire in longitudinal and vertical directions for overall cutting, and has simple processing, good integrity, high processing accuracy, simple assembly and easy accuracy assurance.

[0013] The present invention uses a strip electron beam with the same electrical parameters to interact with the electromagnetic waves propagating in the slow-wave structure. Compared with the existing frame-rod slow-wave structure, it not only has a wider operating frequency band, but also has a higher coupling impedance in the operating frequency band, which can further improve the operating bandwidth and output power of the traveling wave tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the existing frame-rod slow-wave structure.

[0015] Figure 2 It is a schematic structural diagram of Example 1 (frame-center double rods) of the present invention.

[0016] Figure 3 It is a schematic diagram of the structure of Example 2 (frame-diagonal double rods) of the present invention.

[0017] Figure 4 A three-dimensional diagram of Example 1 of the present invention.

[0018] Figure 5 A three-dimensional diagram of Example 2 of the present invention.

[0019] Figure 6 It is a schematic diagram comparing the dispersion curves of the present invention and the existing rectangular frame-single-rod slow-wave structure.

[0020] Figure 7 It is a schematic diagram comparing the coupling impedances of the present invention and the existing rectangular frame-single-rod slow-wave structure.

[0021] In the figure: 1 rectangular shielding tube, 2 dielectric substrate, 4 electron injection channel, 13 rectangular frame - single-pole slow-wave circuit, 23 rectangular frame - central double-pole slow-wave circuit, 33 rectangular frame - diagonal double-pole slow-wave circuit. DETAILED DESCRIPTION

[0022] Embodiment 1:

[0023] A rectangular frame-double-rod slow-wave structure comprises a rectangular shielding tube 1, a dielectric substrate 2, and a frame-rod slow-wave circuit; the frame-rod slow-wave circuit is arranged on the central axis of the rectangular shielding tube 1, a dielectric substrate 2 with a rectangular frame cross section is arranged between the rectangular shielding tube 1 and the frame-rod slow-wave circuit, and an electron injection channel 4 of a traveling wave tube is formed inside the frame-rod slow-wave circuit; the frame-rod slow-wave circuit is a rectangular frame-double-rod slow-wave circuit, which is composed of a plurality of rectangular metal wire frames of the same size and a pair of symmetrically distributed metal connecting rods between adjacent rectangular metal wire frames; the pair of metal connecting rods are alternately located on the center connecting line of the long side and the short side of the rectangular metal wire frame, such as Figure 2 shown.

[0024] Embodiment 2:

[0025] A rectangular frame-double-rod slow-wave structure, comprising a rectangular shielding tube 1, a dielectric substrate 2, and a frame-rod slow-wave circuit; the frame-rod slow-wave circuit is arranged on the central axis of the rectangular shielding tube 1, a dielectric substrate 2 with a rectangular frame cross section is arranged between the rectangular shielding tube 1 and the frame-rod slow-wave circuit, and the frame-rod slow-wave circuit constitutes an electron injection channel 4 of a traveling wave tube; the frame-rod slow-wave circuit is a rectangular frame-double-rod slow-wave circuit, which is composed of a plurality of rectangular metal wire frames of the same size and a pair of symmetrically distributed metal connecting rods between adjacent rectangular metal wire frames; the pair of metal connecting rods are alternately located on the diagonals of the rectangular metal wire frames, such as Figure 3 shown.

[0026] Related parameters of the embodiment of the present invention: The relative dielectric constant of the dielectric substrate 2 with a rectangular cross section is ε r The inner cavity width of the rectangular metal wire frame is a, the inner cavity height is b, the side thickness is t, and the axial thickness is w; the length of the metal connecting rod is L, the rod width is equal to the axial thickness of the rectangular metal wire frame, which is also w, and the rod thickness is equal to the side thickness of the rectangular metal wire frame, which is also t; the period length of a single period (the length between three adjacent rectangular metal wire frames) of the rectangular frame-double-rod slow-wave circuit is p.

[0027] The specific parameters are set as follows: (except for the relative dielectric constant ε r The unit is: mm): The relative dielectric constant ε of the dielectric substrate 2 with a rectangular cross section r =4, w = 0.05, t = 0.02, L = 0.2, a = 1.08, b = 2.16, c = 1.72, d = 2.80, p = 0.5; where c and d are the inner cavity width and inner cavity height of the cross section of the rectangular shielding tube 1, respectively. The rectangular frame-double-rod slow-wave structure with the above parameters was established and simulated using three-dimensional electromagnetic simulation software to obtain its dispersion characteristics and coupling impedance. The simulation results are shown in Figure 6 and Figure 7 shown.

[0028] from Figure 6It can be seen from the comparison that: under the same parameter conditions, the present invention and the existing rectangular frame-single-pole slow-wave structure have almost completely consistent dispersion flatness, but the present invention has a significantly wider working bandwidth. The working bandwidth of the existing rectangular frame-single-pole slow-wave structure is limited to below 14.5GHz, while the working bandwidths of Example 1 and Example 2 both reach 27GHz, and the working bandwidths of Example 1 and Example 2 are improved by more than 80% on the basis of the working bandwidth of the existing rectangular frame-single-pole slow-wave structure. Moreover, the conclusion that the working bandwidths of Example 1 and Example 2 are improved by more than 80% on the basis of the working bandwidth of the existing rectangular frame-single-pole slow-wave structure while maintaining the same size conditions and changing the structural parameters also holds true.

[0029] from Figure 7 It can be seen from the comparison that: under the same parameter conditions, compared with the existing rectangular frame-single-pole slow-wave structure, the present invention has a higher coupling impedance in the medium and high frequency bands. At the center frequency of 7GHz of the existing rectangular frame-single-pole slow-wave structure, the coupling impedance of Example 1 and the coupling impedance of the existing rectangular frame-single-pole slow-wave structure are almost completely equal, both of which are 17 ohms; while the coupling impedance of Example 2 is slightly higher, which is 20 ohms. At the center frequency of 13.5GHz of the present invention, the coupling impedance of Example 1 is above 7 ohms, the coupling impedance of Example 2 is above 10 ohms, and the coupling impedance of the existing rectangular frame-single-pole slow-wave structure is below 1 ohm. In the frequency range of 7GHz-14GHz, the coupling impedance of Example 1 of the present invention is more than 40% higher than the coupling impedance of the existing rectangular frame-single-pole slow-wave structure. Compared with Example 2, Example 1 has a significant improvement in the coupling impedance of Example 2.

[0030] comprehensive Figure 6 and Figure 7 It can be seen that under the same parameters and process conditions, the present invention can operate in a higher frequency band and have a wider operating bandwidth, and at the same time has a higher coupling impedance in the operating frequency band and can obtain a higher output power.

Claims

1. A rectangular frame-double-rod slow-wave structure, comprising a rectangular shielding tube (1), a dielectric substrate (2), and a frame-rod slow-wave circuit; wherein: The frame-rod slow-wave circuit is a rectangular frame-double-rod slow-wave circuit, in which a pair of symmetrically distributed metal connecting rods are connected between adjacent rectangular metal wire frames; The pair of metal connecting rods are alternately located on the center connecting line of the long side and the short side of the rectangular metal wire frame or alternately located on the diagonal corners of the rectangular metal wire frame.

2. The rectangular frame-double-rod slow-wave structure according to claim 1, characterized in that: The lengths of the metal connecting rods between adjacent rectangular metal wire frames are all equal, or the lengths gradually increase, or the lengths gradually decrease, or the lengths vary randomly.

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