CPW Center-Fed Single-Layer SIW Slot Antenna Array for Automotive Radars

摘要

A compact co-planar waveguide (CPW) center-fed substrate-integrated-waveguide (SIW) slot antenna array is proposed to achieve narrow $H$-plane beamwidth and low sidelobe levels for automotive radars such as across-the-road (ATR) radar. The antenna consists of an array of SIW slot elements, a CPW-SIW transition, and a CPW power divider. A new type of CPW-SIW transition is proposed to minimize the blockage aperture of the slot antenna array for suppressing the sidelobe levels of the array. A parallel center feeding configuration is applied to avoid beam squinting. The antenna prototype printed onto a single-layer Rogers 5880 is with 32$times$4 slot elements and an overall size of ${hbox{195 mm}}times {hbox{40 mm}}times {hbox{0.79 mm}}$. Measured results show that the proposed antenna exhibits a gain of $> {hbox{22.8 dBi}}$, an efficiency of $>{hbox{67}}%$, a return loss of $> {hbox{10 dB}}$, a sidelobe level of $< -{hbox{21 dB}}$, and a fixed boresight beam of $< {hbox{4.6}}^{circ}$ in $H$ -planes over 24.05–24.25 GHz, suitable for ATR radar.