Premium
Asymmetric single stub‐tapped stepped‐impedance unit for compact rat‐race coupler with ultra‐wide range harmonic suppression
Author(s) -
Vuppuloori Ravi Sekhara Reddy,
Velidi Vamsi Krishna,
Bhima Prabhakara Rao
Publication year - 2021
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.32643
Subject(s) - stub (electronics) , electrical impedance , electrical engineering , materials science , optoelectronics , acoustics , electronic engineering , physics , engineering
Abstract A design of compact rat‐race coupler (RRC) with very wide‐range spurious suppression is presented using transmission line (TL) based asymmetric single stub‐tapped stepped‐impedance units. The main advantages of proposed unit are 2fold. First, unlike regular single stub TL units, the present unit facilitates realizable high (low) impedance values for smaller electrical length series‐arm (shunt open‐stub) resulting in great extent of size reduction (harmonic suppression) without degradation in coupler bandwidths. Second, the number of open‐stubs in the RRC can be reduced to three by connecting the proposed units back‐to‐back, which is not possible in using other TL units. Theoretical analysis is provided with design equations and graphs. A prototype high performance compact RRC at f 0 = 0.5 GHz, targeted at a size reduction of about 75% and ultra‐wide range suppressed harmonic response, extended up to 12 f 0 , is demonstrated with good 20 dB return loss bandwidth of 26%.