A wide-band single-layer patch antenna

The typical single-layer patch printed on a dielectric substrate is a narrow-band element. This well-known fact is mainly due to the limitations imposed by the dielectric substrate. From efficiency and cost considerations, in most of the cases, the substrate cannot be too thick. In order to increase the microstrip element bandwidth, additional resonators in different configurations and combinations can be used: parasitic elements, slots, etc. However, the microstrip antenna element with the widest bandwidth (a variation of the aperture-fed stacked-patch element) is about 40-50%. This antenna, an aperture-fed stacked patch, has a relatively poor front-to-back ratio, due to the fact that it has a slot in the ground plane. In this paper, a new type of patch element is presented. The patch is suspended over the ground plane and supported by a nonconductive pin. It is fed by a three-dimensional (3-D) transition connecting the patch to a perpendicular connector. The typical bandwidth of this element (in terms of VSWR) is 90%. When built on a large ground plane, the front-to-back of this element is better than 25 dB across the band.