Compact Frequency Reconfigurable Antennas Based on Composite Right/Left-Handed Transmission Line

The compact reconfigurable antennas based on composite right/left-handed (CRLH) transmission line are proposed and analyzed in this paper. The proposed antenna is fed by the asymmetric coplanar strip (ACPS) and consists of coupling radiation patch as well as a PIN diode. The differences of the antennas with meander line and without meander line are discussed. By utilizing a PIN diode as the CRLH transmission line termination, the termination states can be controlled, and the resonance of the antenna can thus be tuned between the two zeroth-order resonant frequencies. By switching the diode, the antenna with meander line is able to operate in single-band of 2.08-2.54 GHz and dual-bands of 1.65-1.84 GHz and 5.35-6.40 GHz, while the antenna without meander line is able to operation between two single-bands of 1.84-2.28 GHz and 4.6-6.0 GHz. All these operation bands cover the UMTS (1750 MHz-1780 MHz), ISM (2.4 GHz), WIMAX (2.5-2.69 GHz) and WLAN (2.4-2.484 GHz/5.725-5.825 GHz) applications. The radiation performance was simulated by High Frequency Structure Simulator, and the measurements were taken in an anechoic chamber to verify the simulation results. Good agreements are observed between the simulated and measured results. Moreover, the radiation patterns of the proposed antennas remain stable at different reconfigurable bands.