Enhancing Gain Through Optimal Antenna Element Distribution in a Thinned Array Configuration

This paper presents an array thinning approach for a 25-element antenna array arranged in a
$5\times5$
grid at 5.4 GHz. Our goal is to eliminate a maximum number of antenna elements with minor gain loss and hence reduce the array size, weight, cost, and power requirements. Consequently, the space saved by the thinned array configuration presents opportunities to integrate additional antennas and hardware, allowing for a low-profile antenna-in-package. Our study showed that a 64% array reduction (from 25 to 9 probe-fed patch antennas) achieved an array gain comparable to a full array configuration. As such, various 9-element configurations for testing were generated through the thinning process and optimized using the genetic algorithm. These configurations were then validated using full-wave simulations. Results show that all configurations that preserved the effective area while maintaining symmetry along all axes showed a minimal effect on gain reduction. Specifically, the best thinning configuration resulted in a loss of only 1.82 dB in simulation at broadside compared to a fully populated
$5\times5$
array. The exact configuration also showed beam scanning performance from −45° to +45° (viz. 90°). A prototype was fabricated and tested for each of the thinned configurations. The measured gain of the optimal 9-element thinned array configuration showed excellent agreement with the simulations.