A Retrodirective Antenna Array With Polarization Rotation Property

A planar passive retrodirective antenna (RDA) array with polarization rotation property is proposed in this paper using the substrate integrated waveguide (SIW) technology, which can be used in monostatic radar applications. The proposed RDA array adopts planar bandwidth-enhanced SIW cavity-backed wide slot antennas as the radiation elements. The polarization rotation property can be achieved by using radiation elements in two different configurations. A W-band prototype RDA array with 16 radiation elements is designed and fabricated using the single-layer printed circuit board (PCB) process at 79 GHz for automotive short-range radar applications. The measurement setup for monostatic and bistatic radar cross section (RCS) responses as well as the calibration process are presented. The retrodirective property and the polarization rotation property are realized by the proposed RDA array. The simulated and measured results of monostatic and bistatic RCS responses are in good agreement, which can cover an incident angle of ±17^° from bore-sight with its normalized monostatic RCS response dropped by about 3 dB.