SINGLE-FEED TRIPLE-BAND CIRCULARLY POLARIZED SPIDRON FRACTAL SLOT ANTENNA

Abstract

In this paper, the design of a single-feed triple-band circularly polarized Spidron fractal slot antenna is presented.The proposed antenna is composed of a Spidron fractal slot, a Z-shaped slit, and two L-shaped slits to realize triple-band circular polarization operation.A simple 50 Ω microstrip line is utilized to feed the proposed antenna.A conducting reflector is also used to reduce back radiation, thereby enhancing the forward antenna gain.The proposed antenna has total dimensions of 40.7 mm×40.7 mm×18.52 mm (0.42λ×0.42λ× 0.19λ) and was fabricated and tested.The experimental results show that the proposed antenna has -10 dB reflection coefficient bandwidths from 2.76 GHz to 3.13 GHz and from 3.56 GHz to 6.22 GHz.The measured 3 dB axial ratio bandwidths are 2.28% (3.04-3.11GHz) for the lower band, 7.15% (4.18-4.49GHz) for the middle band, and 2.6% (4.93-5.06GHz) for the upper band.The peak gains within the -10 dB reflection coefficient bandwidths are 3.41 dBic and 6.29 dBic, respectively.