Circularly Polarized Annular Leaky-Wave Antenna with Suppressed Open Stop-Band and SIW Feeding

A radially periodic 2-D leaky-wave antenna (LWA) with high gain at broadside and suppressed open stop-band (OSB) is presented in this work. It consists of a double strip bull-eye antenna fed with a four-port slotted substrate integrated waveguide (SIW) feed arrangement using a Rogers RT6010 substrate having ϵr equal to 10.2. The proposed antenna is first excited with a simple and ideal magnetic dipole to show its scanning performance. Then, the multi-port SIW configuration is properly excited (i.e., by keeping a phase difference of 90° for the adjacent ports) to provide circularly polarized radiation at broadside. Simulated results show a directive gain of 18 dBic at broadside, corresponding to a frequency of 18.5 GHz, and, persistent broadside radiation is supported from 18.0 GHz to 19.5 GHz which is in agreement with the numerically determined leaky-wave (LW) phase and attenuation constants. Applications include satellite connectivity, radar systems, and wireless communications, basically, where continuous beam steering through broadside is required, or, broadside radiation over a significant frequency range.