Microstrip leaky-wave antenna with control of leakage rate and only one main beam in the azimuthal plane

摘要

An original leaky-wave antenna (LWA), conceivedfrom a microstrip line which is laterally shielded by parallel plates,is presented in this paper. This structure shows, for the first time,that the leakage rate of a microstrip leaky-mode can be easilycontrolled while negligibly affecting the pointing direction. Theantenna is based on the radiation from the second higher ordermode of the microstrip line, which is perturbed by the additionof the two conductor walls to control the level of the leakagerate. The parallel-plates also serve as a mechanism to obtain asingle main beam in the azimuthal plane, therefore improving theradiation pattern compared to common dual-beam second-higherorder mode microstrip LWAs. The proposed antenna is analyzedby obtaining the corresponding leaky-mode complex propagationconstant, which is calculated by a specific method of momentsapproach. The modal results obtained from the leaky-modedispersion curves are validated with analysis performed on athree-dimensional structure using commercial finite elementmethod solver. Also, a prototype is fabricated to experimentallyconfirm the advantages of this novel leaky-wave line source.