N-connectors are medium-sized threaded connectors that are used in a variety of cable assemblies. They are one of the most commonly used radio frequency connectors in circulation. Type N connectors are available in 50 and 75 Ohm versions that are not intercompatible due to marked structural differences. They are also known as:

• Navy connectors
• N-Type connectors
• Type N connectors

The N connector can be paired with coaxial cable that is flexible, semi-rigid, or helical with corrugated copper for a wide range of applications. These rugged brass or stainless steel connectors are widely used in telecom and wireless networking applications that require good power handling and weatherproof connection. N connectors can also be mounted on panels or printed circuit boards by crimping, clamping, or soldering.

Type N connector history

The N connector is one of the earliest microwave radio frequency connectors. It was invented by Paul Neill of Bell Labs in the 1940s as a key military microwave connector for the US Navy Bureau of Ships. The first N connectors were capable of supporting frequencies up to 1 GHz, subsequent refinements to the design has raised its maximum frequency to 11 GHz. The “N” in N connector was thought to stand for “Navy”, but actually refers to the initials of its inventor, Paul Neill.

Applications for the N connector have expanded from its military origins to include diverse civilian and communications infrastructure applications where its ruggedness and suitability to outdoor use is advantageous. Later modifications including adjustments of the dielectric in the connector by Hewlett-Packard and other electronics companies led to the modifications that set the current electronic specifications of this RF connector.

Physical specifications of the N connector

N connectors are threaded male and female connectors that mate by screw coupling. They are made from nickel-plated brass or stainless steel. They carry 5/8 - 24 pitched UNEF threading. As a medium-sized radio frequency connector, the N connector is larger than subminiature threaded radio frequency connectors like the SMA or TNC connectors. The specifications for N connectors include:

• CECC22210
• MIL-PRF-39012 (MIL-STD-348B)
• IEC 61169-16 standardization.

When properly mated, N connectors form a watertight and weatherproof connection that is rated for over 500 mating cycles. The addition of an O-ring seal to the mated connection achieves an IP 67 rating. This means that the connection is free from solid contaminants such as dust and sand, waterproof to a significant depth of immersion, and vibration resistant.

Standard N connectors do not have a dielectric but precision N connectors may carry a small amount of PTFE (Teflon) insulator material within them.

Male N connector

The male N connector has a diameter of 0.800 inches (20.3 millimeters) with internalized threads. It carries a hex nut that can be tightened with appropriate torque wrench. The mating interface of the male Type N connector has a brass pin as its center conductor.

Female N connector

The female N connectors have external threading on the connector body. The outer diameter of the female N connector is 0.620 inches (15.7 millimeters). The female N connector carries a beryllium copper receptacle that receives the male pin when it is fully mated by the male connector screwing down and over it.

N connector electrical specifications

• Standard N connectors have an impedance of 50 ohms. There are 75-ohm versions, but they are functionally incompatible with the 50-ohm N connector and can damage the standard N connectors if mated incorrectly.
• Type N connectors support frequencies up to 11 GHz. Precision versions of the N connector have a frequency limit of 18 GHz.
• Type N connectors have a peak voltage rating of 1500 volts and a dielectric withstanding voltage of up to 2500 volts. The superior power handling makes it a radio frequency connector of choice for high voltage devices like surge protectors. It is often selected in preference to BNC or TNC connectors for a variety of high voltage applications.
• N connectors have a VSWR of 1.3.
• The contact resistance is 1 milliohm with an insertion loss of 0.15 dB.
• Radio frequency leakage of the Type N connector is -90 decibels at 3GHz.