A HIGH SPEED DESIGN AND OPTIMIZATION METHOD FOR MILLIMETER WAVE E-PLANE BANDPASS FILTERS
Millimeter wave waveguide filters are widely used in modern microwave communication systems, especially in personal communication systems. Traditional approximate and empirical design techniques cannot achieve accurate results and manual tuning becomes less efficient in the high order filter design. Since the 1970's, significant progress has been made in the computer-aided design of microwave circuits. With the increase in the availability and capability of computers, research has shifted its focus to the numerical characterization and modeling of waveguide filter components. In this thesis, a high speed computer-aided design method for E-plane waveguide bandpass filters is developed. Discontinuity between an empty waveguide and the bifurcated or trifurcated waveguide is analyzed only once. The obtained scattering matrices are stored and repeatedly used throughout the synthesis and optimization procedures. A new method that uses three optimization variables regardless of the filter order is adopted to optimize the initial design. The CAD program is verified by comparing analysis results with existing results from various sources and several high order filters are realized by the CAD program with desired specifications. With the computer-aided design method developed in this thesis, E-plane waveguide bandpass filter at millimeter wave frequencies range can be designed accurately without post-production tuning. A significant amount of computer memory and analysis time will be saved due to the new synthesis and optimization procedure.