Generalized Coupled-Line All-Pass Phasers

Generalized coupled-line all-pass phasers, based on cascaded C-sections (CCSs), cascaded coupled-lines (CCLs), and hybrid-cascaded (HC) coupled transmission-line sections, are presented and demonstrated using analytical, full-wave, and experimental results. It is shown that for N commensurate coupled-line sections, CCL and HC phasers exhibit N group-delay peaks per coupled-line section harmonic frequency band, in contrast to the CCS configuration, which exhibits only one peak within this band. It is also shown that for a given maximum achievable coupling-coefficient, the HC configuration provides the largest group-delay swing. A wave-interference analysis is finally applied to the various coupled-line phasers, explaining their unique group-delay characteristics based on physical wave-propagation mechanisms.