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Standing wave effects in a symmetrical three‐line microstrip coupler with short‐circuited side lines
Author(s) -
Faria J. A. Brandão
Publication year - 1989
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.4650020209
Subject(s) - microstrip , strips , rat race coupler , conductor , transmission line , wavelength , power dividers and directional couplers , admittance , optics , physics , electric power transmission , ground plane , hybrid coupler , acoustics , electrical engineering , engineering , materials science , electrical impedance , geometry , mathematics , composite material , antenna (radio)
The spectral domain analysis of microstrip couplers with lateral ground strips can be conducted following two different approaches: assuming the lateral strips are continuously short‐circuited to ground or discretely bonded to the reference ground conductor at the coupler ends. In this paper, the second approach is used: The wave number and the characteristic admittance of the central strip propagation made of a coplanar three‐conductor microstrip transmission line are determined and shown to depend critically on the coupler length. The spatial evolution of microstrip voltages and currents inside the coupler is also determined and discussed. The results show that noticeable standing wave effects are present when the coupler length comes close to an integer multiple of one‐half wavelength.