PIN diode switches for frequency-reconfigurable stacked patch microstrip array antenna using aperture-coupled technique

This paper presents a novel design of frequency-reconfigurable antenna by using an aperture-coupled technique as feeding technique and stacked patch technology. The proposed antenna generally consists of three substrate layers (RT-Rogers 5880) and air gap filled between feedline substrate and layer 2 substrates. Four PIN diode (BAP51-02) switches are implemented to configure the length of the feedline by configuring the switches to ON or OFF mode. A new approach of coupling methods is presented. When all the switches are in ON mode, the signal will be passed to the selective aperture slot and activate the particular radiating patch layer to achieve the frequency reconfigurability either at 2.6 GHz or 3.5 GHz. The prototype of the proposed antenna is tested/fabricated with the biasing circuit to validate the performance of the antenna. The simulated and measured results are presented to confirm the performance of the antenna.