Compact and Frequency-Reconfigurable Printed Antenna for Heterogeneous Wireless Systems

A compact and frequency-reconfigurable antenna with four operating bands modes is reported in this paper. The proposed structure is formed by the association of a printed dipole and two capacitively loaded loops (CLL). Specifically, it uses two open circuits used as switches in the designated places to control the resonant bands of the antenna and then achieving frequency-reconfigurable in four operating modes: a single-band mode (F
1
=2.3GHz), two dual-band mode: (F
1
=1.52GHz /F
2
=2.35GHz), then (F
1
=1.8GHz / F
2
=2.30GHz) and a triple-band mode (F
1
=1.52GHz / F
2
=1.8GHz and F3=2.30GHz) covering a number of well-known wireless communication systems, including WiMAX, DCS and UMTS. The performance results show that the proposed antenna scheme explores significant gain (>1.6 dBi in all modes) and reasonable efficiency (>78% in all modes) for each mode. The novelty of the proposed antenna lies on the small size and low design complexity. Also the studied antenna exhibits a reasonably good gain and efficiency in all operating bands. This structure could be combined in compact and heterogeneous radio frequency (RF) front-ends of a cognitive radio (CR) because of its small geometry and efficient utilization of the frequency spectrum.