A novel compact and broadband printed monopole antenna for circular polarization

In this letter, a compact and broadband printed monopole antenna for circular polarization is proposed. In order to reduce the antenna size and achieve the circular polarization, the ground plane is combined by two elliptical shaped conductors with different size, and the antenna is designed asymmetrically to the microstrip line. The simulated and measured bandwidth of the 10dB-return loss with a 3dB-axial ratio is 57.9% (2.65GHz-4.81GHz) and 52.0% (2.45GHz-4.17GHz). The size of the antenna is 0.178 lambda(2)(c) (lambda(c) is a wavelength in free space at the center frequency).