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The purpose of this paper is to compare thick and thin film microstripline response to conducting overlay.

Study changes in transmission and reflection of both thick and thin film microstripline due to overlay of polyaniline (PANI) thin film on stainless steel and silver. PANI was deposited by electropolymerisation method using HCl and H₂SO₄.

Transmittance of both the thick and thin film microstripline decreases due to the PANI overlay and reflectance increases. Thin film microstripline is more sensitive to the type of conducting overlay than thick film microstripline. PANI deposited on silver is more absorbing than PANI deposited on stainless steel using HCl acid. The overlay makes the response of the microstripline more dispersive.

The increase in reflectance and decrease in transmittance can provide information about the type of overlay materials. There is need for newer materials which can replace traditional metals for microstrip components. PANI might serve this purpose.

This study aims to investigate the ammonia-sensing performance of polyaniline/polyethylene oxide (PANI/PEO) and polyaniline/polyethylene oxide/zinc oxide (PANI/PEO-ZnO) composite nanofibers at room temperature.

Gas sensor structures were fabricated using microfabrication techniques. First, onto the SiO₂ wafer, gold electrodes were fabricated via thermal evaporation. PANI/PEO nanofibers were produced by the electrospinning method, and the ZnO layer was deposited by using radio frequency (RF) magnetron sputtering on the electrospun nanofibers as a sensing layer. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction were performed to characterize the analysis of nanofibers. After all, gas sensing analysis of PANI/PEO and PANI/PEO/ZnO nanofibers was conducted using an experimental setup at room temperature conditions. Furthermore, the impact of humidity (17%–90% RH) on the sensor resistance was actively investigated.

FTIR analysis confirms the presence of functional groups of PANI, PEO and ZnO in nanofiber structure. SEM micrographs demonstrate beads-free, thinner and smooth nanofibers with ZnO contribution to electrospun PANI/PEO nanofibers. Moreover, according to the gas sensing results, the PANI/PEO nanofibers exhibit 115 s and 457 s response time and recovery time, respectively. However, the PANI/PEO/ZnO nanofibers exhibit 245 s and 153 s response time and recovery time, respectively. PANI/PEO/MOx composite nanofibers ensure stability to the NH₃ gas owing to the high surface/volume ratio and decrease in the humidity dependence of gas sensors, making gas sensors more stable to the environment.

In this study, ZnO was deposited via RF magnetron sputtering techniques on PANI/PEO nanofibers as a different approach instead of in situ polymerization to investigate and enhance the sensor response and recovery time of the PANI/PEO/ZnO and PANI/PEO composite nanofibers to ammonia. These results indicated that ZnO can enhance the sensing properties of conductive polymer-based resistive sensors.

The purpose of this paper is to report on the Ku band microwave characteristics of moisture laden soya seeds using overlay technique.

Ku band (13‐18 GHz) moisture dependent microwave permittivity, conductivity, penetration depth of moisture laden soybean (Glycine Max) using overlay on Ag thick film equilateral triangular patch antenna are studied. The change in the frequency response of the patch antenna due to change in moisture content of the soybean overlay has been used to obtain the various microwave properties.

The permittivities obtained are in the range expected of moisture laden soybean. As moisture content increases microwave dielectric constant, dielectric loss, and conductivity of soybean increases. Only the amplitude data have been used here.

Ku band characterization of soybean has been done using overlay technique. The thick film patch antenna is sensitive even to ∼4 percent moisture content in the overlay material. This can be used for even moisture sensing at low moisture levels. This paper is believed to be an original research report.

The purpose of this paper is to report the effect of bismuth oxide thick films of various thicknesses on the X band (8‐12 GHz) response of Ag thick film microstrip rectangular patch antenna.

The effect of bismuth oxide thick film overlay of different thickness on Ag thick film microstrip rectangular patch antenna was investigated in the X band (8‐12 GHz). The change in the resonance frequency, amplitude, band width, quality factor, and input impedance of the antenna were studied. Using the resonance frequency the permittivity and conductivity of bismuth oxide thick film was measured.

Thickness of Bi₂O₃ thick film overlay dependent changes in the patch antenna characteristics is obtained. The resonance frequency shifts to higher frequency end due to overlay. The input impedance decreases due to the overlay. The dielectric constant of bismuth oxide thick film calculated from shift in resonance frequency shows thickness dependent values.

The microwave permittivity and conductivity of Bi₂O₃ thick film have been reported for the first time using overlay on thick film patch antenna. Thickness of overlay dependent tuning of the antenna has been achieved.