Sparse antenna arrays reduce hardware cost but introduce sidelobe-related challenges for direction-of-arrival (DoA) estimation. Conventional array-design metrics such as sidelobe level (SLL) and half-power beamwidth do not directly predict how well a given geometry supports target detection, false-alarm control, or angular accuracy. This paper bridges that gap with a receiver-operating-characteristic (ROC)-based framework that quantifies probability of detection (P _D), false alarm rate (FAR), and angular root-mean-square error (RMSE) for equi-amplitude spatially tapered arrays (STAs). Three STA families are synthesized via convex optimization to isolate the effects of aperture scaling, inter-element spacing, and sidelobe-shaping objective, and each is benchmarked against aperture-matched uniform linear arrays through single-snapshot Monte Carlo simulations with two unequal-power sources spanning a 30dB dynamic range. A two-dimensional analysis maps P _D and RMSE jointly over angular separation and inter-source SNR difference, explicitly characterizing weak-target detectability beside a strong interferer. Three estimators - Bartlett beamforming, Orthogonal Matching Pursuit, and FOCUSS - are compared to reveal how pattern-limited and sparse-recovery methods exploit different array geometries. The results show that peak SLL reduction improves detection primarily in the low-FAR regime, yielding up to 0.2 gain in P _D per 10dB of SLL suppression at FAR = 10 ^-3 , while sparse estimators remain robust to irregular layouts. The proposed framework provides a direct, system-level link between STA synthesis parameters and practical DoA performance for radar and joint radar-communications systems.

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.