Feasibility of an automotive radar antenna at 77 GHz on LTCC substrate

The feasibility of microstrip planar antenna arrays printed on a low-temperature co-fired ceramic (LTCC) substrate for an automotive long-range radar application at the frequency of 77 GHz is investigated. The antenna configuration consists of three receiving (RX) and two transmitting (TX) microstrip patch antennas. The full three-dimensional electromagnetic simulations show, despite the high permittivity and losses of the LTCC substrate, that the achievable impedance matching is wider than 1 GHz and the combination of TX and RX radiation patterns satisfies typical requirements in the azimuthal and elevation planes. Problematic, however, is the reduced antenna gain that can be achieved for a given radiation pattern shape due to the relatively high-dielectric losses.