Design of an Aperture-Coupled Frequency-Reconfigurable Microstrip Stacked Array Antenna for LTE and WiMAX Applications

The aim of this paper is to design a novel structure of a frequency-reconfigurable microstrip array antenna by using a combination of aperture-coupled and the stacked patch technology. The four sets of two different aperture slot shapes (I-shaped and H-shaped) are printed on the ground and are functional to transfer the wave and the signal to the selected radiating layers. Both aperture slot positions are based on the bottom patches (layer 2) and top patches (layer 1), respectively. To achieve the frequency reconfigurability, four PIN diode switches are integrated on the feed line layer positioned between both aperture slots on the ground.The activation of the selected patches will determine the current operating frequency of the proposed antenna. A 2.6GHz or 3.5GHz frequency is achieved by switching all the PIN diode switches to ON or OFF mode synchronously. The advantage of the proposed antenna is that it can minimize the usage of the antenna's surface area, with different size of the patch having different operating frequencies, sorted in different layer. The measured results of the return losses, radiation patterns, and the practical indoor propagation measurement achieved good agreement with the simulated results.