An overview of polarimetric sensing and its growing application in automotive radar systems is presented. While polarimetric techniques are extensively used in fields like weather monitoring and target imaging, their integration into automotive radar presents unique challenges, particularly in calibration and measurement accuracy across wide scanning angles. This paper reviews key polarimetric principles and their use in different applications, with a focus on current automotive radar implementations, and the calibration challenges posed by off-broadside measurements. Future research directions for improving polarimetric accuracy in dynamic automotive environments are also discussed.

Both thermal and electromagnetic performance of substrate-integrated waveguide (SIW) and microstrip line-fed shaped-beam arrays with slot and patch radiating elements are conducted. Three array types operating at 26 GHz band, namely SIW slot array, SIW array with patches, and proximity coupled patch array, are considered. The array performances regarding shaped radiation pattern stability with frequency and maximal temperature at the power amplifier chips are discussed. The study highlights intriguing trade-offs between radiation pattern performance and cooling ability in phased arrays.