Investigation on Tunable antenna with Polarization Using Cascaded BLC Feed Network

The combination of varactor diode and a dual feed BLC (Branch line coupler) feed network to build a microstrip frequency and polarization reconfigurable patch antenna is demonstrated. The motivation of the work is carried out by multiple reconfigurations in single antenna. The frequency reconfigurability is explored by adjusting the capacitance of one and four varactor diodes. The proposed circular patch antenna is modeled using EM simulation and tune from 2.34 GHz to 2.68 GHz on varying four varactor diodes with dual-probe feed. The capacitance value is varied between 12.33pF and 1.30pF to achieve tunable frequency bandwidth. Further, larger bandwidth is accomplished by using a cascaded Branch Line Coupler (BLC) feed network to monitor frequency tunability concurrently from 2.05 GHz to 3.13 GHz, which is used for S-Band applications and to achieve polarization reconfiguration.