A W-Band Rectangular Waveguide TE10 to Circular Waveguide TE02 Mode Converter

In this article, a broadband
$W$
-band
$\mathrm{TE}^{\square }_{10}$
–
$\mathrm{TE}^{\bigcirc }_{02}$
mode converter is proposed and verified. To improve the output performance of the
$\mathrm{TE}^{\square }_{10}$
–
$\mathrm{TE}^{\bigcirc }_{02}$
mode converter, a
$\mathrm{TE}^{\square }_{10}$
-to-
$\mathrm{TE}^{\square }_{40}$
intermediate mode conversion section with a Y-type power divider structure and a
$\mathrm{TE}^{\times }_{44}$
-like-to-
$\mathrm{TE}^{\bigcirc }_{02}$
intermediate mode conversion section with a novel cross-sector-shaped transition structure are adopted in the design (the superscript symbol
$^{\square }$
represents the rectangular waveguide,
$^{\bigcirc }$
represents the circular waveguide,
$^{\times }$
represents the cross waveguide). The simulation results show that the transmission coefficient (S
₂₁
parameter) of the designed
$\mathrm{TE}^{\bigcirc }_{02}$
mode converter is better than −0.18 dB in the whole
$W$
-band (75–110 GHz), and the corresponding mode conversion efficiency is larger than 96%. Cold test results show that the transmission coefficient is higher than −1.9 dB and the reflection coefficient (S
₁₁
parameter) is less than −15 dB in the frequency range of 75–110 GHz.