Compact Dual-Band Circularly Polarized GPS Microstrip Antenna Using Double-Section Dumbbell-Shaped Defected Ground Plane and S-Slot Patch

In this paper, a compact dual-band circularly polarized microstrip antenna for precise global positioning system (GPS) applications is proposed. An S-shaped slot is cut at the centre of a square patch radiator for dual-band operation. A T-shaped inset-fed patch antenna is used with dumbbell-shaped defected ground plane to increase aperture coupling between feed line and patch. The frequency-ratio of the two operating frequency bands can be precisely controlled by adjusting the S-shaped slot arm lengths. The bent patch embedded in the substrate is used as a left shifter resonance frequency that means compaction. The simulated 10-dB return loss bandwidths for the lower and upper-bands are 1.63% (1.219-1.239GHz) for and 0.6% (1.572-1.581GHz), respectively. The simulated 6-dB Axial-Ratio (AR) bandwidth is 6.01% (1.210–1.285GHz) for the lower-band and 9.42% (1.436–1.578GHz) for the upper-band. The simulated gain is more than 2.4 dB over both the bands

Keywords:

Circularly polarized antenna , dualband patch antenna , GPS antenna , slotted patch