Low-Profile Phased Array Antenna With Wide Steering Range for Vehicular Communications

A low-profile linear phased array antenna with wide scanning range is investigated for vehicular communications. Each array element deploys broad-beam multi-slots that can be divided into y-directed magnetic currents with same direction and four equal-magnitude x-directed magnetic currents in different directions. The former magnetic current provides a broadside radiation pattern, whereas the latter magnetic currents enhance the low-elevation far-field radiation. Combining the former and latter currents can give a flexible wide-beam H-plane radiation pattern. A prototype was designed and fabricated, and it has a measured 3-dB H-plane beamwidth of 217 degrees at 8.6 GHz. Next, the multi-slot element is employed to construct an X-band 9-element phased array antenna. The phased array antenna was also fabricated and tested. Its main beam can steer from -90 degrees to +90 degrees with a gain fluctuation and peak sidelobe level below 2.1 dB and -5 dB, respectively. Thus, the proposed low-profile phased array antenna with competitive beam scanning performance is suitable for vehicular communications.