The Development of the Microwave Vacuum Electronics at BVERI Fujiang Liao and Jinjun Feng Beijing Vacuum Electronics Research Institute Vacuum Electronics National Lab July 14th, 2010

Outline Introduction Microwave Power Module ( MPM ) The Microwave Integrated Vacuum Electronics Teraherz Vacuum Electron Devices

Introduction Recent years as the phase array antenna system and wide band-gap semiconductor devices develop, some system engineers doubt if the microwave vacuum electron tubes will be replaced by the wide band gap semiconductor devices? What is the directions of the vacuum electron devices for the future? We try to answer this question and intro-duce some work we are doing.

The directions of Microwave Vacuum Electron Devices Some directions of microwave vacuum elec- tron device developments should be: Microwave Power Module ( MPM ); The microwave integrated vacuum electron devices; Gyrotron Teraherz Vacuum Electron Devices.

Microwave Power Module ( MPM ) MPM consists of solid state amplifier, electric power conditioning and vacuum electron power booster. MPM will be used in the phase array antenna system to support the military equipment with low cost microwave power devices. Next figure shows the MPM picture and small size vacuum electron power booster (mini-TWT). This small size power booster is the core of MPM.

Microwave power module MPM Solid State Amplifier Vacuum Power Booster EPT Microwave power module

the phase array antenna system

the phase array antenna system We are trying to use MPM into the active phase array antenna system to replace the semiconductor T/R module. The key techniques are to reduce the power output and the working voltage of TWT. It needs also to reduce the TWT size. One task is to make the plane TWTs.

Fabrication of slow-wave-structure Miniaturized TWTs Fabrication of slow-wave-structure for mini TWT Dielectric stud support with metal vane helix slow-wave structure are developing at BVERI by welding and laser cutting with the support of National key laboratory of high power vacuum electronics .

A plane TWT The Meander line is used to as slow wave structure for plane TWT. PBG material is to use to replace the ceramic substrate to support the Meander line slow wave structure.

Vacuum Micro Electronics Device With the field emission array cathode, the mini TWT can be fabricated. Next picture shows the field emission array cathode with DC current density 10A/cm2 made in BVERI.

Vacuum Micro Electronics Device Field Emission Array Cathode Put Field Emission Array Cathode into the Traveling Wave Tube.

Microwave Integrated Vacuum Electronics Devices Microwave integrated vacuum electron device is made with 3D-MCM technique. Mini TWTs, SSA, phase shifters, filters and EPC are all integrate in the ceramic substrate. Next picture shows the microwave integra-ted vacuum electron device.

Microwave Integrated Vacuum Electronics Devices RF Input Attenuator Phase shifter SSA gun Collector Power out gun Collector EPC

Optical Control TWTs Optical beam and RF input Picture shows the optical control TWT. Microwave is modulated on the optical beam. Then the optical beam is put on the photoelectron cathode to make the electron emission. No RF input here This electron current is microwave modulated. It will make interaction with RF structure of TWT to make signal amplification.

Gyrotron Gyrotron can be worked at Ka band and above. We are doing some research work on the gyrotron at Ka band and W band. Ka band gyro-TWT made in China

Teraherz Vacuum Electron Devices TH vacuum electron device works at more than 300GHz. The folded waveguide TWT, Meander line or helix TWTs are also developed at 100, 140, 220GHz.

Structures using micro-fabrication

Conclusion Professor Carter worked in the vacuum electronics field for more than 40 years and made great contributions in it. We believe that he concern the directions of microwave vacuum electronics. Microwave vacuum electronics is very important devices for military and civilian application in the next 20 years. Microwave vacuum electronics will combi- ne with microelectronics, optoelectronics to form some new devices.

The End Thanks!