Single- and dual-band leaky wave antennas using an electromagnetic band gap structure

We propose new and practical design methods of a low-profile and high-gain leaky wave antenna (LWA). Based on a required dispersion relationship, we suggest appropriate equivalent transmission line models representing a unit cell of the LWA, which determines a specific frequency of maximum radiation together with optimal circuit values essential for maximum gain at a boresight direction. According to the equivalent model approach, we can design overall structure of the high-gain LWA very easily and accurately. In addition, we also propose a novel way of deriving dual-band resonance from a simple single-band-resonating LWA by means of an electromagnetic band gap (EBG) structure. In order to make the LWA resonate at two different frequencies, we intentionally introduce a propagation stop band into an existing one pass band by inserting an EBG structure. By doing so, we can obtain two new specific conditions resulting in maximum radiation toward a boresight direction at the two resonant frequencies locating on both sides of the inserted stop band. All experimental results show good agreement with theoretical predictions, which proves the validity and effectiveness of our approaches.