A Pillbox Window With Impedance Matching Sections for a ${W}$ -Band Gyro-TWA

A mode-matching method was developed to design a pillbox-type millimeter-wave window for a W-band gyrotron traveling-wave amplifier. With additional impedance matching sections, the pillbox window was able to achieve -40-dB reflection over a 10% frequency bandwidth. The manufactured pillbox window was achieved a maximum reflection of -15 dB. The reasons for the difference between the simulated and measured reflections were investigated.