Diversity On-Glass Antennas for Maximized Channel Capacity for FM Radio Reception in Vehicles

This communication proposes a systematic design method to increase the diversity gain for vehicle on-glass antennas using the Pareto genetic algorithm. The initial antenna structure consists of two FM antennas printed on a rear window with horizontal conducting striplines. The position and the number of the vertical lines in the rear window were then determined using the Pareto genetic algorithm to maximize the channel capacity and average bore-sight gain of each antenna. The optimized antennas were built and mounted in a commercial sedan, and the antennas' performances, such as the reflection coefficient, radiation pattern, and channel capacity were measured. The measurements showed a matching bandwidth of around 15% and an average bore-sight gain of more than $-12~{\rm dBi}$ . The measured correlation coefficient of the two antennas was less than 0.6.