Yoshifumi Ohba

Equivalent transformations for the mixed lumped Brune-type section and uniform transmission line

As an analytical method for nonuniform transmission lines (NTLs) equivalent transformations are extended to a more general case, namely a mixed lumped Brune-type section and a uniform transmission line (unit element, UE). Circuits consisting of a cascade connection of a lumped Brune section and a UE are equivalent to one consisting of a cascade connection of a nonuniform transmission line whose characteristic impedance distribution is expressed with a trigonometric function and a lumped Brune section. This equivalent transformation method is easily applied to a circuit consisting of a lumped C section and a UE. The equivalent circuit is a circuit consisting of an NTL and a lumped C section. In this case, the characteristic impedance distribution of the NTL may be expressed in terms of a hyperbolic function. Exact network functions of the NTLs are easily obtained from the equivalent circuits without solving the telegraphers equation. By considering the limiting case of these equivalent transformations, equivalent transformations for circuits consisting of a cascade connection of a lumped resonance circuit and a circuit and a uniform transmission line are derived. >

The mixed lumped and nonuniform distributed circuit band-pass filter

Filters are widely used in communication systems and EMC equipment. We consider about the mixed lumped and nonuniform distributed circuit band-pass filter using nonuniform transmission line (NTL-PR) represented with lumped parallel resonance circuit, uniform transmission line and lumped /spl pi/-type Brune section with negative sign. First, the simple equivalent circuit of the NTL-PR is shown. It can be represented with an imaginary gyrator and a lumped capacitor. Next, the design method for the mixed lumped and nonuniform distributed circuit band-pass filter is shown. The design method uses the simple equivalent circuit. Finally, examples of the transmission characteristics of the band-pass filters are shown.