Photonic crystal-based resonant antenna with a very high directivity

We investigate the radiation properties of an antenna that was formed by a hybrid combination of a monopole radiation source and a cavity built around a dielectric layer-by-layer three-dimensional photonic crystal. We measure d a maximum directivity of 310, and a power enhancement of 180 at the reson ant frequency of the cavity. We observed that the antenna has a narrow band width determined by the cavity, where the resonant frequency can be tuned w ithin the band gap of the photonic crystal. The measured radiation patterns agree well with our theoretical results. (C) 2000 American Institute of Ph ysics. [S0021-8979(00)03601-X].