Su Xiaobao

A micro-strip millimeter wave predistortion linearizer with temperature compensation

Conventional micro-strip predistortion linearizers work at low band, need isolators to match the input and output and mostly lack of temperature compensation. This paper presents a micro-strip predistortion circuit which can obtain about 5dB and 50° gain and phase expansion at the same bias conditions at 29, 30, 31GHz without isolators at both input and output ports. The diodes in the circuit are parallel with negative temperature coefficient (NTC) thermal resistors.

Design of slow wave structures for an X-band broadband TWT

In this paper, the design of slow wave structures for an X-band broadband TWT with suppression of backward-wave using the helix pitch step method is present. An optimized design of a high-power X-band broadband TWT with improved BWO suppression and forward-wave saturated output power is presented.

Research on radiator for space traveling wave tube

Heat radiator for space traveling wave tube has been analyzed using ANSYS, and has been produced. The heat vacuum test shows that the experiment data agrees well with the simulated one.

Development of a Ku-band 150W space TWT

This paper reports the design, simulation work and test results of a 150W Ku-band continuous wave space Traveling Wave Tube (TWT), which is fulfilled at the Institute of Electronics, Chinese Academy of Sciences. The double-anode gun, helix pitch-tapering slow wave structure, non-axisymmetric four-stage depressed collector and radiation-cooled radiator are used in this TWT. The test results indicate that in the case of saturated drive, the TWT can get a power of more than 154W, an efficiency of more than 62%, a phase shift less than 46.6 degree, and AM/PM factor less than 4.3deg/dB with the beam transmission rate of more than 98.5% in the operation band of 12.25-12.75-GHz. The environment testing was performed and the results show that the configuration design of this TWT is satisfied for a satellite mechanics environment and the heat dissipation design is satisfied for an airborne environment.

The modeling and mesh of a simple cathode-heater assembly structure

This paper introduced a way of modeling a simple cathode-heater assembly structure with ANSYS software, and list some resolved problems when meshing the structure. The helix structure was finished by extruding a solid circle along with a group of curves. Meanwhile, fast and reliable mesh method was discussed.

Simulation of cold-test characteristics for TWT slow-wave structures

A method has been established to accurately calculate cold-test data for helical slow-wave structures using the three-dimensional (3D) electromagnetic computer code MAFIA [Kory, 1996]. Compared with the experiment data, absolute average differences across the bandwidth of 0.2% and 3.4 Ohms for the dispersion and impedance, respectively. The computer code MAFIA is also used in this analysis to determine the effect on dispersion and on-axis interaction impedance of the wedge support rod geometry parameter variation.

Effect of helical slow-wave structure parameter variations on TWT cold-test characteristics

In this paper, the quasi-periodic boundary conditions in the computer code MAFIA is used to determine the effect on dispersion and on-axis interaction impedance of helical slow-wave structure and the finite element method software-ANSYS is used to simulate the helix pressure distortion. The result is that, with the variations of axial width and height of the helical tape, only a slight effect in the phase velocity, but more effect in the interaction impedance. There is a best point on both axial width and height of the helical tape for the interaction impedance. Both dispersion and on-axis interaction impedance are increased with helix deformation, in which the radial relative deformation is less then 1%. While radial relative deformation is more then 1%, the on-axis interaction impedance is decreased.