Micro-Coax semi-rigid cable is still the best pure microwave transmission medium available in the world. The solid tubular outer conductor yields 100% RF shielding and enables the dielectric and center conductor to remain precisely spaced. This results in optimum impedance control as well as the lowest possible insertion loss and weight to size ratios. Semi-rigid cables are also inexpensive to purchase when compared to many other coaxial cable alternatives. The primary considerations for using semi-rigid are the availability of bend tooling, the difficulty in routing and the need to reform the cable. Generally, the more flexibility required, the more the designer should consider other alternatives. However, for pure microwave performance semi-rigid can't be beat.
