Development of an E-Band CW Space TWT With Substantial Improvement in Performance

This brief presents the development of an
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-band (71–76 GHz) continuous wave (CW) space traveling wave tube (TWT) with substantial performance improvement. This tube was designed using modified folded waveguide (FWG) and dynamic phase velocity tapering (DVT) circuits, together with four-stage depressed collectors made of graphite. Based on calculation and simulation data, a prototype
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-band space TWT was fabricated, with the testing conducted at a relatively lower beam voltage of 14.1 kV and current of 70.3 mA. The test results show the prototype is capable of providing output power up to 106 W, gain of 41 dB and overall efficiency of 52%, at 71–76 GHz. It is also found within the 5 GHz bandwidth, the electronic efficiency is over 10.6%, while a maximum saturated output power reaches 122 W, with a corresponding overall efficiency of 55%. Given the above data, attained at the relatively lowered operating voltage and current, it is believed the overall performance of this
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-band TWT exhibits a substantial improvement as compared to those of the reported similar tubes.