A new class of wide-band microstrip arrays

Wide-band microstrip antennas are still a challenge and a number of new configurations were reported. Most of these configurations are multilayer patch antennas and some of them achieving up to 40% in bandwidth. Another new geometry was reported previously, a single patch fed by a three-dimensional feed line, which in essence is a very tall patch fed by a wide-band dipole. This antenna is reported to exhibit a 90-100% bandwidth in terms of for VSWR<2:1; towards the high end of the band, however, the radiation from the wide-band dipole is too strong and interferes with the patch pattern resulting in a high cross-polarization level. In the array environment, though, the cross-polarization is reduced by the array factor. The paper analyzes the performance of an eight-element array and its scanning capabilities. To avoid grading lobes the radiating elements have to be very close to each other, so the impact of the mutual coupling is also investigated.