In this paper, a compact (15.5 Â 32 mm 2 ) reconfigurable microstrip antenna with hexa-band operation for radio frequency (RF) energy harvesting applications is presented. Three PIN diodes (D3, D2, and D1) for switching action and internet of things (IoT) controlled unit for controlling the resonating frequency of the proposed antenna are used. The antenna resonates at 2.1 and 3.4 GHz (010 state), 3.3 GHz (100 state), 3.2 GHz (101 state), 3 GHz (110 state), and 2.8 GHz (111 state). The proposed antenna exhibits À10 dB simulated and measured impedance bandwidth of 150, 400, 480, 570, 370, and 400 MHz and 120, 410, 400, 470, 320, 100, 101, 110, and 111, respectively. A maximum peak gain of 3.3 dBi and maximum bandwidth of 570 MHz at 3.2 GHz (101 state) is observed. The proposed antenna is further tested for harvested power, and maximum harvested voltage of 3.9 V, maximum harvested power of 3.013 mW, and 55.07% power conversion efficiency at 20-dBm power source are recorded. The simulated results have been validated with experimental results.hexa-band, power harvesting, reconfigurable antenna, rectenna, remote-controlled switch
| INTRODUCTIONAdvancement in portable smart electronic devices operating at multiple frequencies has led to expeditious enhancement in performance of the microstrip patch antenna for wireless communications. Antenna with multiple resonance and adjustable resonance with reconfigurable antenna are the need for modern communication devices. 1 Antennas with fixed frequency band and radiation pattern can be used for single service. The applications seeking multiple frequency bands need multiple antennas or multiband antenna. More number of antennas results in large space consumption, interference between adjacent antenna elements, complex hardware platform, and huge installation cost. Antennas with compact size, less interference, efficient in transmission, low cost, and least complexity are required in advanced communication electronic equipment. The reconfigurable antennas can be used to overcome the limitations aforesaid 2 efficiently.A reconfigurable antenna provides an alternate method to enhance the antenna bandwidth without change in physical dimension. The reconfigurable antennas have been replaced over conventional multiband and multiple-input