A Miniature Folded Shorted Patch Antenna for Dual-Band Operation

The design and performance of a folded shorted patch antenna for dual-band operation is presented in this paper. The proposed antenna consists of a folded shorted patch that is excited by a coaxial probe. By cutting two slots in different parts of the patch, good input impedance matching has been achieved over two frequency bands. The lower band possesses an impedance bandwidth (SWR < 2) of 21.1% (0.790 to 0.976 GHz) and a peak gain of 7.3 dBi, while the upper band has an impedance bandwidth (SWR < 2) of 32.2% (1.698 to 2.350 GHz) and a peak gain of 7.5 dBi. Other than the wideband and high gain features, this antenna also has a low profile of 0.5λ_L and a small size of 0.25 λ;_L × 0.36 λ_L, where λ_L is the free space wavelength at the center frequency of the lower band. Therefore, this antenna is very suitable for the indoor base station that is required to service several wireless communication systems, included CDMA800, GSM900, PCS, UMTS, BLUETOOTH and WLAN, by a single compact antenna.