A feeder shift technique to improve the performance of small Radial Line Slot Array (RLSA) antennas

This paper proposes and experimentally verifies a novel feeder shift technique to improve the performance of small Radial Line Slot Array (RLSA) antennas. The technique optimizes slot pair placement by shifting the antenna feeder from the center toward the edge, allowing previously occupied regions to accommodate additional slot pairs and thereby increasing the antenna aperture utilization. Since antenna gain is theoretically proportional to the number of slot pairs, the technique is expected to enhance gain. To verify this hypothesis, 150 small RLSA antenna models were simulated, and the best-performing design was fabricated and experimentally measured. The simulation and measurement results show good agreement, demonstrating that the proposed technique can approximately double the antenna gain and increase the bandwidth by about 60%. These results confirm that feeder shifting is an effective approach for significantly improving the performance of small RLSA antennas.