Preliminary design of TM₁₁-TE₁₀ mode converter in rectangular waveguide

The design of a separate and plate-inserted mode converter for rectangular TM11-TE10 was presented. A metal flashboard, paralleling the wide edge, was inserted at the middle of the narrow edge, separating the rectangular waveguide into two equal parts, which transformed TE10 modes with reverse phases. A group of metal plates, paralleling the narrow edge, were inserted with the same space, both in two parts. While the difference of metal plates coaxial length between different parts was suitable, the TE10 modes of the two parts got 180 phase difference. Thereafter, the TE10modes from different parts were transformed with the same phase and compounded into one single TE10 mode by an impedance degression part. The mode converter could keep the same axis and transverse size of output port of high-power microwave source driven by sheet election beam. Its axial length was short and had simple and compact structure. The design was validated and preliminarily optimized by software with finite element algorithm. The transmission efficiency reached -0.45 dB, while bandwidth exceeded 10%, meeting the needs of high-power microwave source driven by sheet electron beams. All the results above offer a new technology for the design of high-power microwave generators with sheet electron beams and its radiation system.