Frequency-Tunable Multiband Reconfigurable Microstrip Patch Antenna for Wireless Application

Microstrip antennas have many advantages as they are low-profile, suitable for conformal structure, and integrated with electronic circuits. The antenna characteristics can be easily modified by shape transformation. In this work, a multiband microstrip antenna is developed. The antenna operates in 2.4 GHz, 3.5 GHz and 3.15 GHz reconfigurable as well as tunable modes. A pin diode switch and another varactor diode switch are used for the frequency band reconfiguring and tuning respectively. The switches are integrated into two coupled parasitic transmission lines without disturbing the main radiator structure. Using a pin diode, the operating band is switched between 3.15 and dual 2.4 and 3.5 GHz bands. Simultaneously by applying a reverse bias voltage to the varactor diodes, frequency tuning is done in respective bands. The simulated model of the antenna is fabricated and tested. The measured results are found satisfactory.