Tianyi Li

Progress of wide bandwidth W-band 20W CW TWT

This paper introduced progress of W-band folded waveguide continuous-wave (CW) TWT. Over 20W output power in 9GHz bandwidth was obtained in W-band. New design thoughts enables this prototype has a much more compact size in contrast to previous 10W level product before.

Development of G band folded waveguide TWTs

A compact folded waveguide traveling-wave tube (TWT) with PPM system operating at 220 GHz with 10 W of output power and 10 GHz bandwidth is being developed. This paper reports the test results of the latest prototype.

Latest experiment results of integrated TWT

This paper introduced latest experiment results of integrated travelling wave tube (TWT) which aimed to explore the possibility of active phased array system using vacuum electronics devices. Some design considerations and results of slow wave structure, beam optics, focusing magnet, coupling window and depressed collector was introduced. The tube output over 90W output power among the frequency of 14-16GHz for three independent amplifier channels. The results verified the concept of integrated TWT very well and show a very promising future in vacuum electronics application in AESA system.

Four channels integrated TWT electron optical system design and optimization

Integrated TWT based on the multi-beams interaction in the limited space is proposed in this paper. Four channels integrated TWTs electron gun and the beam transmission of the tube is simulated by software opera-3D. The design has been a viable integrated TWT electron optical system solutions,and the electron gun statics fluent can reach at least 99%, which provides the foundation for the design of the tube.

I. The progress of 346GHz BWOs

346GHz backward wave oscillations (BWOs) have been considered as a key device for fusion plasma diagnostics, whose development is a joint project under collaboration among Beijing Vacuum Electronics Research Institute (BVERI), University of California Davis (UC Davis) and Lancaster University. In this paper, we report on some progress being made in the development of a 346GHz BWO.

Experimental study on a 220 GHz traveling wave tube prototype without a sever

A 220 GHz traveling wave tube (TWT) is being developed in our lab. This TWT is based on a folded waveguide circuit with an electron beam focused by periodic permanent magnets (PPMs). To measure the transmission loss of the TWT directly, a prototype without a sever has been built. The maximum output power of this prototype is 1.1 W at 225 GHz. The gain, output power and transmission loss are close to the simulation values. On this basis, a new TWT prototype with a sever is being built to produce higher output power and gain.

UV-LIGA microfabrication for high frequency structures of a 220GHz TWT amplifier

In this paper, we fabricate copper high frequency structures for a 220GHz TWT amplifier using UV LIGA technology. The two halves have been assembled and bonded. The measurement results of the folded waveguide circuit show that the attenuation factor of the circuit is 240 dB/m.

Electron optics design and experiment of G-band TWT

This paper introduces the design method and experiment of intensive beam electron optics which contains an electron gun and a magnetic focusing system for a 220GHz folded waveguide TWT. Pierce type electron gun is used. The thermal initial velocity effects as well as the beam waist radius and gunshot distance are considered for the design of electron gun. The period permanent magnet (PPM) system which contains the U-type magnet is simulated by Microwave Tube Simulation Suite (MTSS) and Opera 3D software. The simulation result shows that the transmission current in the tunnel of 0.12mm radius is 53mA with about 90% transmission rate. The experiment achieves about 82.7% of transmission rate and 45mA of transmission current.

Elliptical electrode three-stage depressed collector for one-dimensional compressed miniaturized TWT

The elliptical electrode collector has much smaller height comparing to traditional one with same inner surface area. Quadrupole lens which focus high-energy particles very effectively was used on the first electrode of collector to compress the electron beam in one dimension. Based on the simulation, the elliptical electrode collector was manufactured and tested. Experiment results show that the elliptical electrode collector, which electrode height of the elliptical collector was compressed by 33%, has same performance in RF property.

Progress of integrated TWT

This paper introduced progress of integrated travelling wave tube (TWT) which aimed to explore the possibility of active phased array system using vacuum electronics devices. The three beams multistage collector and coaxial window design results are presented. The first whole tube was assembled and tested. This paper will give the cold test results of coupling port and the hot test results.