An Equidistantly Stepped Waveguide TE11 -TE01 -Mode Converter for Millimeter Wave Radar Applications

In this paper, we present a stepped circular waveguide TEll-TEol-mode converter for millimeter wave radar applications in the range of 69 to 91.7 GHz resulting in a relative bandwidth of approximately 28%. The converter is milled and copper/gold-plated into 34 printed circuit boards (PCB) with identical thickness, resulting in a compact setup that grants an alternative way of manufacturing in comparison to precision mechanic processes. To achieve optimal conversion, three-dimensional electromagnetic field simulations with CST Microwave Studio 2018 are performed. Moreover, measurements with a realized back-to-back converter configuration, a frequency-modulated continuous-wave (FMCW) radar, and a commercial power meter confirm the outstanding functionality of the converter and its robustness against varying production process parameters.