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The distributed‐element to lumped‐element equivalence for transmission‐line filter synthesis
Author(s) -
Xiao Fei
Publication year - 2018
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.2521
Subject(s) - microstrip , distributed element filter , electronic engineering , prototype filter , element (criminal law) , filter (signal processing) , transmission line , topology (electrical circuits) , distributed element model , partial element equivalent circuit , equivalent circuit , stripline , engineering , computer science , low pass filter , electrical engineering , voltage , political science , law
Summary Filters play an important role in frequency selection. However, to design transmission‐line filters such as microstrip filters is a very challenging task because of their distributed‐element effect. In this paper, the concept of the distributed‐element to lumped‐element equivalence is applied in the design of microstrip filters. The lumped‐element equivalent networks of some basic microstrip structures are presented and are applied to derive the whole lumped‐element equivalent networks of microstrip filters constituted by them. Then, the physical mechanism of microstrip filters is revealed, ie, how the resonances are created and coupled and how the transmission zeros are formed. The distributed‐element to lumped‐element equivalence relations between the electrical parameters of microstrip filters and the element values of their lumped‐element equivalent networks are derived. Through comparison between the lumped‐element equivalent networks of microstrip filters and those obtained by direct synthesis technique we recently proposed, initial structural parameters of microstrip filters can be calculated, which greatly simplifies their design. To verify it, several microstrip filter examples are presented for demonstration.