Low-profile CPW-fed slot antenna with parasitic slot on conductor-backed two-layer substrate

A previously reported design consisting of a CPW-fed slot antenna with a parasitic slot on a conductor-backed single-layer substrate is extended to an electrically thin, low-profile conductor-backed two-layer substrate. In doing so, several enhancements are effected, including relative insensitivity of main beam direction to slot dimensions, a non-leaky CPW-feed line, easier matching, and a gain that exceeds 11 dBi at the operating frequency. Low cross-polarization levels were also achieved.