N Connector - Power Rating

Power Rating

The peak power rating of an N connector is determined by voltage breakdown/ionisation of the air near the center pin. The average power rating is determined by overheating of the centre contact due to resistive insertion loss, and thus is a function of frequency. Typical makers' curves for a new clean connector with a perfect load (VSWR=1.0) give limits of ≈5000 W at 20 MHz and ≈500 W at 2 GHz. This square root frequency derating law is expected from the skin depth decreasing with frequency. At lower frequencies the same maker recommends an upper bound of ≈1000 V RMS. To achieve reliable operation in practice over an extended period, a safety factor of 5 or more is not uncommon, particularly when generic parts may be substituted, or the operating environment is likely to lead to eventual tarnishing of the contacts.