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

摘要

As a first attempt, a series of composite materials of general formula (Bi4Ti3O12)(X) - (CaCu3Ti4O12)(1-X) (BTOX - CCTO1-X) (X = 0-1.0) is synthesized by a sol-gel combustion method. The phase changes, including their formation and evolution during the gradual substitution of BTO into CCTO are analyzed from the X-ray diffraction pattern. The Jana2006 refinement plotting method proves that formation of an ideal dual-phase composite system with separate orthorhombic and cubic phases occurs. A surface morphological study revealed that the BTOX - CCTO1-X composites are composed of small CCTO grains embedded in large BTO grains and both coexisted with a bimodal distribution. The possible vibrational modes of interactions between the constituent phases are determined from Raman spectra. Our inexpensive, combustion method for BTO0.2 - CCTO0.8 gives a high dielectric constant (epsilon' = 3232) at 100 Hz at room temperature. The nature behind these data is revealed that the BTO-CCTO composite can be applicable for the fabrication of miniaturized global positioning system (GPS) patch antennas. The fabricated GPS patch antenna shows optimum results of small size (2.37 mm x 1.18 mm), return loss (-14.419) and wide band-width (350 MHz) to be operated at 1.57 GHz.