Open AccessGeneralised capacitive‐loading method for miniaturisation of forward‐wave directional coupled‐line couplers with arbitrary strip impedances and coupling levels
Author(s) -
Ha Jungje,
Lee Yongshik
Publication year - 2016
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2015.0689
Subject(s) - capacitive sensing , capacitive coupling , electrical impedance , capacitor , coupling (piping) , shunt (medical) , impedance matching , acoustics , power dividers and directional couplers , strips , transmission line , electronic engineering , electrical engineering , engineering , physics , voltage , materials science , mechanical engineering , medicine , cardiology , composite material
This study demonstrates a capacitive reactive loading method for forward‐wave couplers based on coupled lines. With the method, a miniaturised forward‐wave coupler can be designed by loading either a symmetric or an asymmetric coupled line with shunt capacitors symmetrically or asymmetrically. The method is a generalised version of all previous shunt capacitive loading methods for miniaturisation of forward‐wave coupled‐line couplers since it provides complete control of not only the maximum coupling level, but also the impedances of the two strips. For the first time, a forward‐wave coupled‐line coupler is demonstrated that provides an arbitrary maximum coupling level based on 50‐Ω lines. Therefore, lengthy and/or complicated impedance matching networks can be eliminated, a more effective miniaturisation is enabled, and performance degradation associated with the additional circuitry is minimised. Experimental results of various forward‐wave couplers based on quasi‐symmetric and asymmetric coupled lines with various coupling levels and strip impedances are provided to demonstrate the versatility of the proposed method.