Design of single fed aperture coupled microstrip antennas for WLAN

The advantages of microstrip antennas have made them a perfect candidate for use in the wireless local area network (WLAN) applications. This paper presents theoretical investigation and simulation of input impedance behavior of nearly square single fed aperture coupled microstrip patch antenna that can satisfy the narrowband WLAN applications with 2.4 GHz band with 80 MHz bandwidth. For maximum coupling the patch should be centered over the slot, moving the patch relative to the slot in the H-plane direction has little effect, while moving the patch relative to the slot in the E-plane (resonant) direction decreases the coupling level, also for maximum coupling, the feed line should be positioned at right angles to the center of the slot. Skewing the feed line from the slot reduces the coupling, as positioning the feed line towards the edge of the slot. Position of the feed line in different places relative to patch also was presented.