Planar antennas for compact multiband transceivers using a microstrip feedline and multiple open-ended ground slots

Abstract

Two planar antennas for compact multiband transceivers are presented, that employ an open-ended microstrip feedline that couples to multiple open-ended ground slots. The effect of separately introducing each of the slots on the antenna performance is outlined, and it is shown that the resonant frequencies of the antennas can be independently controlled by adjusting the dimensions of the ground slots. Antenna 1, consisting of an open-ended microstrip feedline that couples to three open-ended ground slots, exhibits a measured |S11| < -6 dB in the frequency ranges of 1.64-3.50 GHz, and 5.22-6.81 GHz, covering the standards of DCS, PCS, UMTS, Wibro, Bluetooth, WiMAX, HiperLAN 2 and WLAN with a measured gain that varies between 1.85 and 3.98 dBi, and with radiation efficiencies in excess of 80%. Antenna 2, consisting of an open-ended microstrip feedline that couples to four open-ended ground slots, exhibits a measured |S11| < -6 dB in the entire frequency range of 2.74-6.71 GHz, covering the standards of WiMAX, HiperLAN 2 and WLAN with a measured gain that varies between 4.98 and 5.28 dBi, and with radiation efficiencies in excess of 80%. Both antennas occupy a total size of only 40 × 30 × 1.6 mm3.