Space Machine custom fabricates a standard product line of double ridge dual loop couplers covering waveguide sizes WRD750 thru WRD200. These loop couplers are ideally suited for 25% bandwidths with coupling variation of ± 0.5dB. Over the full waveguide band, coupling variation is + 2.5dB. Directivity is 15dB minimum. Main arm VSWR is 1.15:1 and secondary arm VSWR is 1.3:1.