Over the years many different techniques have been utilized to bring about the physical realization of directional Air Quick Coupler . The scope of this article is limited to discussion of quarter-wavelength, coaxial, directional couplers, as this type of coupler represents a balanced compromise between functional range, performance and cost for most broadband applications covering up to an octave bandwidth.
The basic directional coupler is a four port junction that is used in a wide variety of microwave systems to satisfy almost any r
