Design of a Compact TE□40 Mode Converter Based on Power Divider Principle

A W-band TE
^□
40
mode converter with a compact structure based on three T-junction power dividers for measuring high-order overmoded mode slow-wave structures is presented. Since the T-junction discontinuity causes the port reflection, a series of matching steps were introduced in the converter. The proposed converter possessed a bandwidth of 12 GHz with the transmission coefficient S
21
higher than -3 dB and port reflection S
11
lower than -15 dB. More importantly, the transmission coefficient of the unwanted modes is lower than -15 dB within the bandwidth of interest.