Design of Broadband Planar Inverted F Antenna Using the Resonant Frequency to the next Reactance Equal to Zero

In this paper, we propose a novel design of broadband and easy fabrication F antenna for ISM band. The antenna structure is flexible and capable of being realized in various application cases. Reduced short circuit plate (RSC), and low resonant frequency (LRF) for PIFA design are applied to design a compact F antenna with the aid of a 2.5D field simulator, IE3D. Not only does RSC give better impedance matching, but the LRF provides broader bandwidth. Both designed PIFAs are operated at wireless LAN of IEEE 802.11b,g. Measurements indicate that the LRF achieves -10dB bandwidth up to 304 MHz(12.4%) ranging from 2.332 GHz to 2.636 GHz, and the peak gain is 3 dBi. The RSC has a bandwidth up to 220MHz (9%) ranging from 2.36 GHz to 2.58 GHz, and the gain is 2.5 dBi. Actually, our design F antennas reach broadband, miniaturization, lower return loss, and easy to fabricate.