Theory and Demonstration of High Aperture Efficiency Dual-band Leaky-Wave Antenna with Open Stopband Suppression

In this paper, a theory formulated by S-parameter analysis is proposed for dual-band leaky-wave antenna (LWA) featuring open stopband (OSB) suppression and high-aperture efficiency at two different bands. For continuous scanning, this theory is used for quantitative analysis of unit cells, leading to OSB suppression. To achieve high aperture efficiency, S-parameter analysis is set to help modulate the leakage rate to realize balanced radiation in dual frequency bands. Several types of unit cells and their LWA are studied as a demonstration of the design principle. A dual-band LWA with a shared aperture based on mode composite ridged waveguide (MCRW) is derivated as an example to validate the S-parameter analysis. The MCRW is a sort of mode composite structure made of substrate-integrated waveguide (SIW) and substrate-integrated ridged waveguide (SIRW). Through the S-parameter analysis and the use of MCRW, the proposed dual-band aperture-shared LWA has shown numerous advantages such as compact size, high channel isolation, large continuous scanning angle, high aperture and radiation efficiency, and improved gain performance. The measured results agree well with the simulation counterparts, which verifies the effectiveness of the S-parameter analysis method.