Search

A low profile dual-circularly polarized printed ring-slot antenna with a small footprint, which radiates above an open cavity loaded with an artificial magnetic conducting reflector, is presented. The feed network consists of two T-shaped capacitive feed structures connected to a miniaturized hybrid branch-line coupler. Experimental results for a final antenna design (with a size of $0.5\lambda _{\mathrm {\mathbf {0}}} \quad \times 0.5\lambda _{\mathrm {\mathbf {0}}} \quad \times 0.057\lambda _{\mathrm {\mathbf {0}}}$ ) show a 4% isolation bandwidth between the two ports of the dual-circularly polarized antenna and a maximum gain of approximately 6.8 dBic. Good front-to-back ratios and low cross-polarization were achieved. These very compact and low profile antennas are suitable for 2.4 GHz wireless local area network (WLAN) communication systems.

Design results of a small, low profile printed ring-slot antenna with uni-directional radiation properties will be presented. A single linearly polarized, a dual linearly polarized, and a dual circularly polarized version of the antenna will be shown. The ring-slot antenna radiates above an open cavity loaded with an artificial magnetic conducting (AMC) reflector (see Figure 1). This work is an extension of a previously proposed cavity-backed linear slot antenna (J. Joubert, J.C. Vardaxoglou, W.G. Whittow and J.W. Odendaal, IEEE Trans AP, vol. 60, no. 2, Feb. 2012, pp. 735–742). The newly proposed ring-slot radiator is significantly smaller than the linear slot radiator, and has the ability to be fed in such a way that dual linear and dual circularly polarized radiation can be achieved.