Ashutosh Kedar

Efficient analysis for nonlinear microwave characteristics of high-power HTS thin film microstrip resonators

This paper investigates the nonlinear effects of high-Tc superconducting (HTS) thin film in high-power applications. A nonlinear model for complex surface impedance has been proposed for the efficient analysis of the nonlinearity of HTS thin films. Further, using the developed model, analysis of HTS-MSR has been done using the spectral domain method (SDM). The SDM formulation has been modified to account for finite conductivity and thickness of HTS films by incorporating a complex resistive boundary condition. The results have been validated with the experiments performed with microstrip resonators (MSRs) based on YBa2Cu3O7−x (YBCO) thin films made by a laser ablation technique on LaAlO3 substrates, characterized for their characteristics, namely, resonant frequency and quality factor measured as a function of temperature and input RF power. A close agreement between the theoretical and measured results has been achieved validating the analysis.

CAD Analysis of HTS Microstrip Patch Antenna Using a Spectral Domain Method

An accurate full wave spectral domain technique is developed to evaluate the characteristic parameters of high-temperature superconducting (HTS) microstrip antennas (MSA). The analysis takes into account most of the practical operating conditions affecting the performance of MSA. A corresponding study of copper (Cu)-MSA has also been carried out to visualize the advantage of HTS-MSA over its normal counterpart.

Characterization and analysis of high temperature superconducting microstrip and coplanar resonators using a spectral domain method

Microwave characteristics of planar high temperature superconducting microstrip line resonator (MSR) and coplanar waveguide (CPW) resonators have been estimated using a full wave spectral domain technique in conjunction with the complex resistive boundary condition. The computer aided design method developed is applied to simulate the characteristics of planar resonators. The proposed method has been validated with experimental results after taking into account the practical operating conditions. A reasonable agreement for the theoretically computed and measured resonant frequency and unloaded Q-value with experimental data of Porch et al (1995 IEEE Microw. Theory Technol. 2 306?14) has been observed for the MSR operated at 5?GHz as well as for the CPW resonator at 7.95?GHz.

Parametric study of microstrip patch antennas

Theoretical analysis of microstrip patch antennas of different shapes using the spectral domain method has been dealt with in this paper. Fourier transformed and Hankel transformed impedance Green functions have been obtained for rectangular and circular patch antennas respectively. Using Galerkins procedure, the resonant frequency is computed by solving the integral equations for the unknown currents in the antenna. The variation in the resonant frequency as a function of the dimensions of the antennas and the dielectric constant of the substrate has been studied. Some of the numerical results have been compared with the experimental data.