The delta-models of reactive elements and low-pass filters

Abstract

Frequency limitations of lumped and distributed reactive elements traditional models are considered. Based on equivalent ciruit of infinitely short transmission line section inductance and capacitance models with properties correspond to delta-function are received. These models called delta-models are without frequency restrictions. In the delta-model graphic designation delta-function length is directly proportional to inductance or capacitance value. Unlike to ordinary graphic designations delta-models allow to represent scheme reactivities values ratios. Traditional models and delta-models reactive elements frequency characteristics are compared. It is found that because of frequency limitations traditional planar microstrip quasi-lumped reactive elements characteristics have substantial errors. Considerable reduction of errors is ensured by microstrip quasi-lumped reactive elements on the basis of three-dimensional inhomogeneities. Based on reactive elements delta-models Butterworth and Chebyshev low-pass filters delta-models are presented. Low-pass filter delta-model "prompt" possibility of filter selectivity increasing. Frequency characteristics of Chebyshev low-pass filter designed on traditional planar microstrip quasi-lumped reactive elements and three-dimensional inhomogeneities are given.