GPS patch antenna performance by modification of Zn(1−x)CaxAl2O4-based microwave dielectric ceramics

Abstract

This study reports the characterization, fabrication, and performance of global positioning systems (GPS) patch antennas as a function of calcium (Ca) concentration and dielectric constant (ɛ r ). Zn(1−x)CaxAl2O4 (x = 0.00, 0.05, 0.10, 0.20, 0.25, and 0.30) thin films were prepared through a sol–gel method. The effects of added Ca on the nanostructures and dielectric properties of ZnAl2O4 ceramics were investigated. The addition of Ca increased the crystallite size, grain size, and surface morphology, thereby increasing the density and dielectric constant. As the Ca content increased, the ɛ r values linearly increased. However, the Q u values decreased (at x = 0.25 to x = 0.25) after achieving the optimum values at x = 0.20. Finally, GPS patch antennas were successfully fabricated using the Zn(1−x)CaxAl2O4 material. The patch antenna sizes decreased as ɛ r increased from 2.88 × 4.37 cm (ɛ r ≈ 8.52) to 2.88 × 4.37 cm (ɛ r ≈ 10.16). The performance (return loss analysis) and operating frequencies of the GPS patch antennas were measured using the PNA series network analyzer. Results show that the patch antenna resonates at frequency of 1.570 GHz and produces a return loss bandwidth between −16.6 and −27.5 dB. The optimal performance of GPS patch antenna with ɛ r ≈ 9.95, Q u ≈ 6,186, and return loss = −27.5 dB was obtained from specimen using Zn0.80Ca0.20Al2O4 (x = 0.20) ceramics.