Design of Frequency Reconfigurable PIFA Antenna with Floating Ground Plane

Objectives: The rapid evolution of wireless communications systems open the field to frequencncy reconfigurable antenna. In this paper, we propose to study and design a PIFA antenna with frequency agility characteristic. Methods/Analysis: The reference antenna resonate at F = 1000 MHz. It consist of a PIFA design printed on the top side and the grounded PCB in the back one. To obtain a low profile and have a multiband behavior, a floating ground plane was printed in back side of the antenna coupled with the radiating PIFA element. A two resonances frequencies can be obtained. To electronically reconfigure the antenna in a determined band and acquiring a large tuning range, a varactor diode was embedded in the corner of the radiating element. Findings: When adding a floating ground plane, a two resonances frequencies can be obtained at 920 and 2800 MHz with better than -10 dB impedance match. To obtain three resonance frequencies with wide tuning ranges, we apply a reverse voltage V on the varactor diode. Frequencies can be shifted from 650 to 2457 MHz covenring GSM850/1900/UMTS/LTE700/LTE2300 and ISM band. The reference and the active antennas were designed and described. Good agreement between simulations and measurement results. Application/Improvements: This work show that tunable PIFA antenna are promising candidate for handheld portable.