A circularly polarized CPW-fed square slot antenna with embedded Hilbert-curves and rectangular patches for GPS/GLONASS operations

This paper presents a circularly polarized CPW-fed square slot antenna with embedded Hilbert-curves and rectangular patches for GPS/GLONASS operations. The proposed antenna is constructed with two Hilbert-curves lines, three rectangular patches and the enhanced feed strip of CPW. By way of adjusting the relevant parameters, we can obtain the GPS band at 1.575 GHz and GLONASS band at 1.609 GHz. The measured −10 dB return loss impedance bandwidth are 480 MHz (30.48%) from 1.35 to 1.83 GHz. The measured 3 dB axial ratio bandwidth is 160 MHz (9.8%) from 1.55 to 1.71 GHz. The polarization of radiation patterns are RHCP and the antenna gain are 3.98 dBic at 1.575 GHz, 3.46 dBic at 1.609 GHz, respectively.