Electrically and Frequency-Tunable Printed Inverted-F Antenna with a Perturbed Parasitic Element

This study designed an electrically and frequency-tunable printed inverted-F antenna (PIFA) with a perturbed parasitic element between the antenna and the ground plane. The resonant frequency of the proposed antenna can be changed via the short- and open-circuit operation of the parasitic element. This operation is activated using an electrical switch, which in this case is a PIN diode with an inductor and a resistor. The antenna was designed on the basis of the principles of the perturbation method, which enables control over resonant frequencies through modifications to the volume of a metal cavity. Meandered gaps were incorporated into the parasitic element for the independent operation of each PIN diode switch. The size of the PIFA’s radiator is 4.8 × 10 mm2, and the tunable resonant frequency at the –10 dB bandwidth is 340 MHz (17.3%).