An Asymmetric Highly Efficient Multistage Depressed Collector for Space TWTs

Asymmetric multistage depressed collectors (MDCs) are preferred in traveling wave tubes due to their high performance in terms of high collector efficiency and low back-streaming current. However, the main drawbacks associated with these asymmetric MDCs are due to their difficulty in fabrication and often bulkier size, as it generally requires an additional magnet or pole piece. Here, we have designed and developed an asymmetric MDC, where asymmetry in electric field has been achieved by suitable electrode geometry modification. Furthermore, the modification in the material of collector envelope has also been done to allow asymmetric leakage of magnetic field within the MDC, without requiring any magnet or pole piece. This MDC offers: 1) high collector performance (with a simulated collector efficiency of 95% in zero drive and zero back-streaming current); 2) ease of fabrication; 3) no increase in size and weight; 4) nonrequirement of additional magnet or pole piece; 5) no high-voltage breakdown issues; and 6) no thermal management issues. Therefore, due to these aforementioned advantages, the MDC stands as a potential candidate for use in space applications.