A Broadband and Compact Circular TE ₀₁ Mode Generator for X-Band High-Power Gyro-TWT Study

A broadband and compact circular TE<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode generator for X-band high-power gyro-TWT study is proposed in this letter. To widen the operating bandwidth and make the generator compact, a cross-waveguide with ridge structure enabling sidewall coupling and a mode transition structure based on a sectoral waveguide are introduced. Based on the analysis, an X-band TE<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode generator is designed, fabricated, and measured. The prototype achieves a conversion loss below 0.25 dB in the range of 7.6–12.9 GHz, with a relative bandwidth of 51.7% and the reflection is below −20 dB. Near-field tests demonstrate a high-purity TE<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode output with mode purity exceeding 99.2%. The proposed generator features a wide bandwidth, high purity, compact design, and easy to machine.