Analysis of tunnel diode loaded stacked microstrip antenna

The theoretical investigations on tunnel diode loaded stacked microstrip antenna is presented using circuit theory concept based on modal expansion cavity model. The investigations reveal that better tunability, better matching and enhanced bandwidth of the stacked antenna can be achieved by adjusting bias voltage of tunnel diode only while the antenna topology remains unaltered. The operational frequency band of the tunnel diode loaded stacked antenna is dependant on bias voltage and can be varied from 400 MHz (bandwidth 10.50 %) to 540 MHz (bandwidth 13.20 %) with the bias voltage. On the other hand, the stacked antenna (without tunnel diode) shows frequency band of 210 MHz (bandwidth 4.49 %). The theoretical results are compared with the simulated results performed on IE3D Zeland Software version 14.05.