Microstrip hybrid ring coupler

摘要

A microstrip hybrid ring coupler providing the same function as a conventional magic Tee in waveguide or a coaxial rat-race. The ring is comprised of four equal electrical length arcs between the input-output ports. The 180 DEG phase shift is introduced in one of the four ring arcs by a tightly coupled parallel strip conductor which extends towards the interior of the ring and has an electrical length of lambda /4 where lambda is the wavelength at the midband operating frequency of the coupler.