Theoretical Modeling and Analysis of Circularly Polarized Annular Leaky-Wave Antenna Based on Travelling-Wave Structure

In this paper, a theoretical model based on the electric field integration method is proposed to analyse radiation properties of the slotted annular Leaky-Wave Antenna (LWA), which can generate a Circularly Polarized (CP) conical beam or broadside beam. The annular LWA contains radiating elements arranged along a circular travelling-wave structure with equal intervals. By combining the proposed model and LWA theory, the design procedure for the annular SIW LWA is presented. To verify the model, three examples of LWAs with different beam angles have been designed and fabricated. Calculation results from the proposed model are consistent with the simulation and measurement results. The model can significantly reduce the design period and is an instructive tool for antenna design.