Two-Section Half-Width Microstrip Leaky Wave Antenna

Antenna beamwidth is a critical parameter that dictates the performance of a radar system. For a microstrip leaky wave antenna (MLWA) to achieve a narrow beam, it requires not only a long aperture, but also a small attenuation constant. In this paper, a two-section MLWA is proposed to achieve a small attenuation constant. The complex propagation constant of the proposed structure is first derived using the transverse resonance method (TRM). An antenna cross section is then designed using TRM and a short prototype is built and measured. It is shown that the resulting complex propagation constant agrees well with that calculated using TRM. Next, the antenna design is extended to a long aperture to demonstrate its narrow-beam performance based on full-wave simulation. Finally, the implications of employing a narrow-beam MLWA for radar applications are discussed.