This paper introduces a dual-band circularly polarized antenna modeled on an FR4 substrate with an optimized dimension of 48 mm × 29.5 mm × 1.6 mm. A maximum usable circularly polarized bandwidth of 90% is obtained in the lower band (3.08 GHz to 3.75 GHz). A square slot etched in the ground plane loaded with asymmetric plus-shaped slits and tabs aids the impedance bandwidth enhancement. The dual-band operation is accomplished by facilitating parasitic square patches in the slot. The simulated impedance bandwidth of the proposed antenna is 740 MHz (3.07 GHz to 3.81 GHz) for the lower band and 1.57 GHz (4.64 GHz to 6.21 GHz) in the upper band. The impedance and axial ratio bandwidth percentages for lower and upper-frequency bands are 21.5%, 19.6%, and 29.4%, 10.54%, centered at 3.5 GHz and 5.5 GHz, respectively. The simulated and measured results are in reasonably good agreement.

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Microstrip-line fed annular ring circularly polarized antenna is proposed in this work. The antenna is fabricated on a disk-shaped FR-4 substrate with annular ring slots etched in the ground. The overall space requirement of the antenna is 25 Â 25 Â 1.6 mm 3 . The antenna is modeled for triple notch wide band circular polarization operation in the frequency range from 2-4 GHz. A wide impedance band operation is be obtained by the introduction of slots and stubs. An impedance band-width of 1.8 GHz is accomplished with three notches at 2.4, 2.8, and 3.3 GHz.