A two-element, electrically small Yagi antenna

In this paper, we present the design for a two-element, closely-spaced, small Yagi structure to achieve high gain. The element design is based on a small folded spiral. All of the antenna dimensions are optimized by using a genetic algorithm (GA) and the Numerical Electromagnetics Code (NEC). The antenna is designed for 900MHz and the prototype of the monopole version of the antenna is constructed and measured. The occupied volume of the antenna is 0.066lambda x 0.095lambda x 0.095lambda (or 5.9e-4 lambda³). The maximum realized gains of the antenna from simulation and measurement are found to be 9.5dB and 8.8dB, respectively.