Characterization and Dielectric Properties of Novel Dielectric Ceramics Ca_xZn_(1−x)Al₂O₄ for GPS Patch Antennas

Abstract

A solgel method was used to prepare Ca x Zn (1Àx) Al 2 O 4 thin films and fabricate GPS patch antennas. The addition of calcium (Ca) has increased the e r , crystallite size, and grain size, to increase the ceramics density. The three highest Q 9 f values appear at the position of x = 0.05 (31,091 MHz), 0.15 (63,906 MHz), and 0.25 (40,609 MHz), respectively. The best combination of microwave dielectric properties (e r~9 .02), Q 9 f~63,906 MHz and with the lowest return lost (À25 dB) is obtained for specimen using Ca 0.15 Zn 0.85 Al 2 O 4 (x = 0.15) ceramics, which is the suggested material for GPS patch antennas.

Synthesis and fabrication of GPS patch antennas by using Zn(1 − x)Ti x Al2O4 thin films

“…The band at 2348 cm -1 can be attributed to the presence of oxygen bonds in the fcc crystal lattice of oxygen atoms. This peak is observed in all spinel compounds and can be treated as a characteristic feature of spinel structured crystallites [3]. The spectra of …”

“…It is noted that the number and shape of FTIR bands (below 1000 cm -1 ) of Ti x Zn (1 -x) Al 2 O 4 thin films is dependent on TiO 2 concentration. In most published papers [3,18], ZnAl 2 O 4 showed two main bands at around 499 and 670 cm -1 . Farhadi and Panahandehjoo [18] reported that the two bands which appeared due to ZnAl 2 O 4 were formed as a mixture of the normal spinel (Al 3?…”

“…The antenna sizes decreased about 44 % between ZnAl 2 O 4 (4.35 9 2.87 cm) and Zn 0.70 Ti 0.30 Al 2 O 4 (3.53 9 2.21 cm) by using the different e r . Wan Jalal et al [3] and Abdullah et al [28] reported that the materials with almost high dielectric constant were able to reduce the antenna size.…”

“…The miniaturization of GPS antenna mainly results from the use of the materials with high dielectric constant (e r ) as either patch antenna or antenna substrate. Tsunooka et al [2] and Wan Jalal et al [3,4] reported that the microwave dielectric ceramics used in the millimeter wave technology must have a high dielectric constant, but limited to e r \ 15. However, the miniaturization of the GPS patch antenna should meet GPS standard operational requirement (operating frequency 1.575 GHz, return loss \ -10 dB, bandwidth [ 2 MHz) [5].…”

Development of performance‐improved global positioning system (GPS) patch antenna based on sol‐gel‐synthesized dual‐phase (Bi4Ti3O12)X – (CaCu3Ti4O12)1–X composites

“…reported that materials with high dielectric constant are particularly interesting for GPS applications at the L1 frequency of 1.575 GHz. Several papers were published in novel ceramic materials such as Zn (1– X ) Mg X Al 2 O 4 , (1− X )ZnAl 2 O 4 ‐ X SiO 2 , Zn (1– X ) Ca X Al 2 O 4 , Ti X Zn (1– X ) Al 2 O 4 and Ca X Zn (1– X ) Al 2 O 4 that are used for GPS patch antennas. The relative permittivity of these ceramics is measured in the frequency range from 20 Hz to 1 MHz at room temperature and average values of the dielectric constant are found to be around 6.00–8.57.…”