Microstrip antenna on a high dielectric constant substrate:: BaTiO3 (BTO)-CaCu3Ti4O12(CCTO) composite screen-printed thick films

The performance of microstrip antennas using composite thick films of (BTOBaTiO3) and CCTO (CaCu3Ti4O12) as a substrate were studied. The dielectric permittivity and loss of (BTO)(x)-(CCTO)(1-x) thick films with x = 0, 0.2, 0.5, 0.8, 0.9, and 1 were examined. These films were prepared in two-layer geometry using the screen-printing technique on Al2O3 substrates. Mechanical alloying followed by the solid-state procedure was successfully employed to produce powders of CCTO (CaCu3Ti4O12) used in the films. We also studied the films dielectric permittivity (K) and loss (D) in the medium-frequency (MF) range (100 Hz to 1 MHz). The performance of a planar microstrip antenna that uses the (BTO)(x):(CCTO)(1-x) thick films as a substrate of high K was also examined in the microwave range of frequencies. From the analysis of the antenna operation of the samples, one can conclude that the higher values of K in the range of 2.5-3.3 GHz antennas is presented by the BTO substrates. For the BTO film, the K value is similar to 66 (2.6 GHz) and decreases to 34 for the CCTO film (3 GHz). For the BTO and CCTO films, the antenna bandwidths (BW) are similar to 50% and similar to 38%, respectively. The higher bandwidth presented by the BTO compared to the CCTO is certainly associated with the higher loss presented by the BTO phase, which is a ferroelectric phase. Therefore, these measurements confirm the potential use of such materials for small microwave planar antennas, where the miniaturization of the devices is crucial.