Triple-band circularly polarized slotted patch antenna for GPS and UMTS systems

This paper introduces a modified printed double sided triple-band and dual-sense circularly polarized patch antenna fed by a 50 Ω microstrip line loaded by a conductor rectangle. A previous design was introduced by Xiulong Bao & M. J. Ammann in 2008, it operates at 1.5 GHz and 2.6 GHz where the radiated fields are circularly polarized at these two bands. The proposed design in this paper is a modified version of the previously proposed one by adding a conductor rectangle at the end of the microstrip feed and etching three more slot arms in the ground. The modifications proposed in this paper enable the antenna to operate at three bands instead of two as in the previous design. This proposed antenna operates at the two bands of GPS systems (at 1.2 GHz and 1.575 GHz), and at the UMTS band (at 2.03 GHz). The radiation is circularly polarized at each band. For the first two bands the wave is RHCP while for the third band it is LHCP. A comprehensive numerical sensitivity analysis has been done to discuss the effects of various dimensional parameters and to optimize the performance of the designed antenna using an accurate simulation tool. The dielectric substrate used in the fabrication process is the FR4 material, of relative permittivity 4.4 and of thickness=1.5 mm. The fabricated antenna is measured in the microwave lab in the GUC. The simulated and measured results for the return loss show a good agreement.