| Recently the milli-meter wave radio frequency system is being developed and used extensively. Better antenna performace is required in this circumanstance. Compare with some other common milli-meter antennas, including microstrip-patch antenna, waveguide slot antenna and reflector antenna, CBSA posses properties of 1) low loss (to microstrip-patch antenna), 2) wideband (to waveguide slot antenna and microstrip-patch antenna) and 3) easy to fabricated.This thesis contributes to the optimization design of the wideband millimeter-wave CBSA, using Finite Difference Time Domain (FDTD) method and genetic algorithms (GA). A breif developing history of CBSA is introduced and some CBSA design conculsions are summarized qualitively. FDTD method is then introduced and applied to the proposed CBSA impedance and radiation characteristic calculation. Some referenced FDTD problems are studied, including antenna modeling method, exciting signal processing and absorbing boundary setting. The main principle and characteristics of GA are studied and a specified GA for CBSA optimization is designed.A new millimeter-wave CBSA was designed and optimized via GA combined with FDTD and the designed antenna is fabricated and measured. There is good agreement between the simulation and measurement so that the design is proved correct. The substrate integreate method is introduced at last, and a new substrate integrated CBSA is proposed.. |
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