Novel low los microwave & millimeter-wave planar transmission lines

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Lu, Yuyuan
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This thesis focuses on the investigation of novel low loss microwave & millimeter-wave planar transmission lines using Finite-Difference Time-Domain (FDTD) method. Initially, a conventional substrate microstrip patch antenna fed by microstrip transmission line is studied using the FDTD. Discrete Fourier Transform (DFT) is used to transform voltage value from the time domain to frequency domain. The reflection coefficient S$\sb{11}$ versus frequencies is obtained. The distribution spatial field components, at different time steps are computed and plotted out. Next, the FDTD is extended to analyse micromachined microstrip transmission lines. Micromachined microstrip transmission lines with thick and thin upper substrates, as well as with the inverted micromachined microstrip transmission lines are studied. Numerical results for the effective relative permittivity, the dielectric loss, the conductor loss and the characteristics impedance are presented with different groove sizes. Finally, for the first time trenched and micromachined coplanar waveguide transmission lines with and without ground planes are investigated using the FDTD. (Abstract shortened by UMI.)