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Minimization of Micro Discharge in Space TWT for Long Life Satellite Communication

International Journal of Electrical and Electronic Science
Vol.3 , No. 1, Publication Date: Mar. 1, 2016, Page: 1-7

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Authors

[1]	Vishnu Srivastava, Microwave Tubes Division, CSIR-Central Electronics Engineering Research Institute (CSIR-CEERI), Pilani-333031, Rajasthan, India.

Abstract

Critical technologies for minimizing micro discharge inside a space TWT are presented for long life and high reliability tube operation for satellite communication. UHV grade materials of low vapor pressure and low gas diffusion rate are used for tube fabrication. High purity alumina insulators are used in gun and collector assemblies with high voltage breakdown margin twice the operating voltage and leakage current less than 0.01µA. Ceramic to metal joints are fabricated to minimize triple-junction effects and to avoid charging of insulators due to any stray electron. High purity low loss alumina insulators (99.5%) are used for RF windows. RF coupler is fabricated to avoid multipactor discharge with a margin of 4 times the operating power output. All assemblies are brazed using Cu-Au alloys, and are checked for leak rate less than 10^-12 torr litre/sec. The tube is UHV processed at 550°C for more than 100 hrs for ultimate vacuum inside tube less than 10^-10 torr to minimize discharging over the tube life.

Keywords

Amplifier, Ceramic Insulators, Discharge, Microwave Tube, Space TWT, Satellite Transponder, UHV Device, UHV Materials

Reference

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