A Broadband <i>E</i>-Band Single-Layer-SIW-to-Waveguide Transition for Automotive Radar
Kaiqiang Zhu, Yu Xiao, Wenhao Tan, Hao Luo, Houjun Sun
Abstract
An <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E$ </tex-math></inline-formula> -band air-filled rectangular waveguide (RWG) to single thin-layer (0.127 mm) substrate integrated waveguide (SIW) transition is proposed for automotive radar applications. The compact transition structure is realized using a symmetric narrow aperture coupled comb patches. With the mutual coupling effect between patches, a bandwidth greater than 22% for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$|S_{11}| < -15$ </tex-math></inline-formula> dB is achieved. A back-to-back prototype is fabricated and measured. The results show that the insertion loss of a single transition is less than 0.5 dB within 71–86 GHz, which covers the whole attractive frequency range for automotive radar. With broadband and compact size, the proposed transition presents potential for automotive radar.