Abstract
Zn(1 - x)Ti (x) Al2O4-based microwave dielectric ceramics were prepared by sol-gel method. The obtained compounds were characterized and fabricated as GPS patch antennas. The XRD patterns show a three-phase system with a spinel ZnAl2O4, anatase and a rutile (TiO2). The addition of TiO2 increased the crystallite size and grain size, and surface morphology tended to increase the ceramics density (4.61-4.75 g/cm(3)) and dielectric constant, epsilon (r) (8.56-13.51). Based on the material investigated and microwave antenna theory, GPS patch antennas were fabricated using Zn(1 - x)Ti (x) Al2O4 and then measured using a PNA series network analyzer. The surface of the GPS patch antennas and ground plane was coated with 200-nm-thick silver to enhance ohmic contact. The patch antenna sizes decreased as epsilon (r) increased from 2.88 x 4.37 cm (12.58 cm(2)) to 3.53 x 2.21 cm (7.80 cm(2)). Among these antennas, the Zn0.70Ti0.30Al2O4 shows an excellent performance combination between return loss (-28.71 dB), small size (3.53 x 2.21 cm), and wide bandwidth (270 MHz).