Design of a Nondirectional Wideband Waveguide Coupler

Wideband waveguide-based couplers have many utilities in microwave and particularly millimeter wave frequency ranges. This paper presents the design for a versatile full waveguide band nondirectional coupler used in conjunction with noncoherent single-port reflectometers, and for other pertinent applications. The design offers several parameters that once simultaneously optimized can provide a constant coupling level throughout the desired frequency band. The design procedure and simulation results for a Ka-band (26.5-40 GHz) coupler are presented. Such a coupler was then designed and constructed to operate in X-band (8.2-12.4 GHz) and the measured and simulated coupling levels show good agreement.