A Meta-surface Broadband Output Window for Gyro-TWT

A meta-surface output window for Ka-band TE
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mode gyrotron traveling wave tubes (gyro-TWT) is proposed, which can effectively match the dielectric constant perfectly and expand the bandwidth of the output window. The physical mechanism of the output window is investigated by theory and simulation. On the basis of theoretical calculation, the main structural parameters were optimized by high frequency simulation software. When the window operates in TE
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mode in Ka-band(26.5GHz-40GHz), the frequency range of the reflection less than -20dB is from 27-40.6GHz and transmission is over 0.11dB. The tolerance analysis are investigated and analyzed, which show that the thickness h$_{1}h_{2}$ and the gap g have less effect on the performance within ± 0.01 mm.