Tapered Approach Trims Coupler Loss

A line of broadband coaxial/air-dielectric directional couplers from R&D Microwaves achieves low loss and high power-handling capabilities by means of innovative design techniques. The couplers employ a tapered or stepped BeCu center conductor of sufficient diameter to handle high power levels, and/or a stepped housing (covered by patent). As an example, model C1-A68 is a single directional coupler that can handle 800 W average and 1 kW peak power from 0.7 to 13 GHz with 0.3 dB insertion loss through 8 GHz and 0.6 insertion loss through 13 GHz. The coupling accuracy is within 1 dB of 10 dB from 1 to 13 GHz and within 1 dB of 11 dB from 0.7 to 1.0 GHz. The directivity is 10 dB or better across the full bandwidth while coupling flatness is 0.5 dB. Third-order intermodulation is -160 dBc measured with two +43 dBm tones. The 50-Ohm coupler is supplied with Type N female connectors, but available with other connections, including SMA, as an option.