Investigation of proximity coupled antenna structures

Proximity coupled microstrip patch antennas (D.M. Pozar and B. Kaufman, Electron. Lett. vol. 23, no. 8, pp. 369-369, 1987) offer various advantages over conventional edge or probe fed patches. In this paper we investigate the standard proximity coupled printed antenna design and highlight the critical design parameters. We also present a stacked proximity coupled antenna, which achieves a broad bandwidth without the need for coupling slots in the lower patch element or a complicated, non-planar feed structure.