Design of circularly polarized planar leaky‐wave antenna using characteristic mode analysis

Abstract

Abstract In the present study, a characteristic mode analysis (CMA) is proposed for the first time to design a periodic leaky‐wave antenna (LWA). By applying CMA to the unit cell of a periodic travelling wave structure, the open stopband is suppressed and circular polarization (CP) radiation is achieved. Also, some parametric studies are added to clarify the design processes. Eventually, to optimize the design, the series and shunt analysis is applied to the unit cell of the periodic travelling wave structure. Based on the proposed analysis, a wideband CP long microstrip LWA (MLWA) is designed and simulated. The MLWA can sweep the main beam from around −30° to +10° continuously through broadside by sweeping the frequency from 7.5 to 12.25 GHz. The proposed structure is designed to have CP in the entire operating frequency. Eventually, the fabricated antenna showed excellent agreement between measured, modelled, and simulated results.