How to Test an RF Coaxial Cable using a Vector Network Analyzer

RF coaxial cables are high precision test assemblies, which along with a calibration kit, adapters and a torque wrench ensure the integrity of the measurements taken by test equipment such as a Vector Network Analyzer. An ideal cable transfers maximum RF energy while incurring as little loss as possible. To choose the best cable for a test solution, one has to consider several factors such as: operating frequency, characteristic impedance, insertion loss, return loss/VSWR, power handling capacity, operating temperature, flexibility, size, weight, shielding and ruggedness, with cost as a primary trade-off.

In this application note, Copper Mountain Technologies presents a simple and practical “do-it-yourself” cable test procedure, along with test results derived from the procedure. The results shown correspond to a 50 Ohm 26” N-type male to SMA male FleXus cable, using one of CMT’s high precision two-port Vector Network Analyzers: the Cobalt 1220. C1220 is a state-of-the-art instrument developed using modern design and production technologies. The same tests can also be performed using other 2-port and 4-port VNAs.