Investigation of the microwave dielectric properties of Ca1-xMgxLa4Ti5O17 ceramics for application in coplanar patch antenna

In this paper, the dielectric properties of Ca1-xMgxLa4Ti5O17 ceramics at microwave frequency have been studied. The diffraction peaks of Ca(1-x)MgxLa4Ti5O17 ceramics nearly unchanged with x increasing from 0 to 0.03. Similar X-ray diffraction peaks of Ca0.99Mg0.01La4Ti5O17 ceramic were observed at different sintering temperatures. A maximum density of 5.3 g/cm(3) can be obtained for Ca0.99Mg0.01La4Ti5O17 ceramic sintered at 1500 degrees C for 4h. A maximum dielectric constant (epsilon(r)) and quality factor (Q x f) of Ca0.99Mg0.01La4Ti5O17 ceramic sintered at 1500 degrees C for 4h are 56.3 and 12,300 GHz (at 6.4 GHz), respectively. A near-zero temperature coefficient of resonant frequency (tau(f)) of -9.6 ppm/degrees C can be obtained for Ca0.99Mg0.01La4Ti5O17 ceramic sintered at 1500 degrees C for 4h. The measurement results for the aperture-coupled coplanar patch antenna at 2.5 GHz are presented. With this technique, a 3.33% bandwidth (return loss <-10 dB) with a center frequency at approximately 2.5 GHz has been successfully achieved. (C) 2009 Elsevier B.V. All rights reserved.