A capacitively-coupled series-fed patch leaky-wave antenna and optimization concepts for efficient broadside radiation

This paper presents a novel series-fed patch leaky-wave antenna (LWA) and furthermore demonstrates optimization strategies for achieving efficient broadside radiation. The proposed LWA is based on the concept of a proximity coupled microstrip patch antenna. Here, two feeding lines from both sides couple capacitively to the microstrip patch edges to form a unit cell element of the LWA. This capacitively-coupled series-fed patch (CSFP) LWA offers several advantages over a conventional series-fed patch LWA, as it provides, a broadband 50 Ohm input impedance, electrically independent tuning parameters and most importantly the total elimination of the open-stopband problem (standing-wave phenomena) at broadside. Finally, CSFP prototypes for 24 GHz are presented with input impedance, scattering parameter and gain measurement results for validation of the proposed designs.