Wideband Dual-Polarized Planar Phased Array Using Filtenna Elements for Vehicular Satellite Communications

A wideband dual-polarized planar phased array with filtering characteristic is presented. The array element, working as a filtenna, is implemented with a dual-polarized stacked patch coupled by a cross-shaped slot. The parasitic patch not only generates an extra resonant mode to broaden the bandwidth but also introduces a radiation null at the upper edge of passband. Another radiation null at the lower edge of passband is introduced by loading the parasitic strips around the driven patch. The filtering mechanism is further verified by constructing an efficient equivalent circuit model. Two sets of carefully designed feedlines are arranged orthogonally in a limited size (meet the space requirement of a phased array) and combined with the cross-shaped slot to improve the out-of-band suppression level in both upper and lower stopbands. The proposed element is subsequently deployed in building a low-profile dual-polarized phased array. A prototype is finally implemented, and the measured results agree well with the simulated ones. A +/- 60 degrees scanning range accompanied with a gain fluctuation within 5.2 dB is observed in the operating passband ranging from 12.3 to 15.8 GHz. The average out-of-band suppression level among different beam directions is found better than 12 dB.