Open AccessMiniaturised rat‐race coupler with second and third harmonic suppression using synthesised transmission lines
Author(s) -
Lai C.H.,
Ma T.G.
Publication year - 2013
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
ISSN - 1350-911X
DOI - 10.1049/el.2013.2975
Subject(s) - harmonics , electric power transmission , transmission line , hybrid coupler , bandwidth (computing) , attenuation , rat race coupler , cascade , capacitor , harmonic , electrical engineering , physics , materials science , optoelectronics , acoustics , engineering , optics , telecommunications , voltage , power dividers and directional couplers , chemical engineering
A miniaturised rat‐race coupler capable of suppressing the second and third harmonics is proposed. The coupler is designed with slow‐wave synthesised transmission lines using two π ‐networks in cascade. Each π ‐network is formed by a parallel LC tank and two shunt capacitors, and is associated with a transmission zero for harmonic attenuation. The two transmission zeros embedded in the synthesised line can be controlled independently. The proposed rat‐race coupler, centred at 2.4 GHz with an operational bandwidth of 18.8%, and at least 21‐dB suppression at the second and third harmonics, features a compact footprint, which is only 12.9% the size of its conventional counterpart.