Bandwidth enhancement of patch antennas loaded with complementary split-ring resonators

This letter presents a broadband, high efficiency patch antenna that utilizes a novel complementary split ring resonators (CSRRs) embedded on the ground plane. The demonstrated approach results in a significant improvement in impedance bandwidth, efficiency, compactness and directivity in comparison to a conventional microstrip antenna. A coaxial-fed microstrip antenna (MA) is integrated with a simple CSRRs structure that is cut from the ground plane. Then, two crossovers are introduced to the conventional CSRRs structure in order to both compactness of the structure and reverse the current flow along the strips. Inserting crossovers with via bridges to the CSRRs structure facilitates a nearly complete impedance match to the source over a wider bandwidth and also maintain a high, 89%, radiation efficiency. The designs and their performance characteristics were simulated with the High Frequency Structure Simulator (HFSS) and verified using the time domain CST Microwave studio simulator and Sonnet EM software. Test results of the fabricated designs show a good correlation with simulated outcomes, validating the design principles.