Theoretical and experimental results for metal-strip-loaded image-guide antennas

Theoretical and experimental results are presented for a planar leaky-wave antenna that consists of an image-guide periodically loaded with metal strips on its top surface. This kind of antennas are very attractive for millimeter wave applications, because their low cost, small size and ease of manufacture, using integrated circuit technology. The mode-matching technique together with the effective dielectric constant (EDC) method have been used to analyze the antenna and to design the prototypes. Mode-matching, based on a space harmonic expansion of the fields in each region, is used to analyze accurately the structure with infinite lateral extent, taking into account the thickness of the metal strips. This method is extended by using the EDC approach to analyze the finite width antenna. The method one allows to obtain the fields inside and outside the antenna, the phase and leaky constants, β and α, and the radiation patterns. The authors present careful measured data for several prototypes, and show that the theory developed previously is accurate