How to choose RF connectors

4 things you need to know when choosing an RF connector 

The factors that consumers to select an RF coax connector should take into account include not only the electronic performance but also economic factors. 

You should mainly concern about four aspects: 

performance must meet the needs of system wiring and economy conform requirement of value engineering. 

The following four aspects need to be considered:

1. Connector interface (SMA,SMB,BNC etc.)

2. Terminative form (PC board, cable, and panel, etc.,)

3. Mechanical structure & plating (for military or commercial)

4. Coaxial connectors interface

Coax connector interface is often determined by its application.

At the same time, it needs to meet electric and mechanical performance.

BNC connector with bayonet lock, which often used in radio signal connection with frequency under 4GHz, is widely used in the network system, instrument, meter, and internet.

TNC’s interface looks like BNC’s except the screw coupling. It can be used when the frequency up to 11GHz and performs well in Vibration.

SMA connector is widely used in aviation, Radar, microwave communication, digital communication, etc. its characteristic impedance is 50ohm, match flexible cable whose frequency is under 12.4GHz and Semi-Rigid cable whose frequency can be up to 18GHz. It owns strong mechanical performance and can be used in a wide range of frequency for its screw coupling.

The size of the SMB is smaller than SMA. It is mainly used in digital communication fields and taking the place of L9. The 50ohm one can be used up to 4GHz and 75ohm one corresponds to 2GHz. A quick connection is an advantage for its snap-on coupling.

SMC is similar to SMB. For its screw coupling mechanism, it owns strong mechanical performance and a wider range of frequency. It is mainly used in military or high vibration environment.

TYPE N is a kind of low-medium power connector, with screw coupling mechanism. The characteristic impedance is 50ohm or 75ohm, and frequency is up to 11GHz. This type is widely used in radio equipment and electronic instrument, especially in testing apparatus.

TYPE MCX connectors provided by HANGZHOU ZION COMMUNICATION company is widely used in the telecommunication fields in narrow space of the equipment for its small size and reliable connection.

The factors that consumers to select a connector should take into account include not only the electronic performance but also economic factors. You should mainly concern about four aspects: performance must meet the needs of system wiring and economy conform requirement of value engineering. The following four aspects need to be considered:

2. Electric performance, installation, and cables

(1) Characteristic Impedance

The Characteristic impedance of the connector must match that system and RF coaxial cable. Connector interface must meet the characteristic impedance 50 ohm or 75 ohms. If not, it will descend the system performance.

(2) Voltage

Make sure that working voltage of the connector is under the maximum tolerance voltage.

(3) maximum working frequency

All kinds of connectors have a maximum working frequency; some 75ohm products designed for commercial usually have a minimum working frequency limit.

(4) transmit cable

The TV cable is often used in the system only thinking over impedance for its small shield effect.

TV flexible cable is a transmutation of the TV cable. It is widely used in computer for its relative continuous impedance, better shield effect, flexible and low price, but could not be used in systems that require high shield effect.

  Shielded flexible cable dispels inductance and capacitance, mainly used in apparatus and buildings. Flexible coaxial cable becomes the most popular airtight transmit cable for its special performance. Coaxial means both signal and grounded conductor are on the same coaxial. Its outer conductor is made of micromesh twist, so is called weaved coaxial cable. The electrical characteristics of this cable offer excellent attenuation performance which refers to the basketwork materials and its thickness.

   We usually use semi-rigid cables at high frequency, whose tubular crust take the place of outer conductor that improve shield effect.

(5) installation method

  There are two methods mainly to install connector: A. solder center conductor and screw on shield layer. This method is designed for the situation without special install tool. B. Crimp center conductor crimp shield layer. Such a method needs crimping tools. All the other installation methods are derived from these two methods, for example, solder center conductor, crimp shield layer. Because the crimp method brings high working efficiency and reliable performance by using the special crimp tool, and it is unanimous to guarantee the quality of every connector, this method will become more and more popular.

3. terminative form

  The connector provides by HANGZHOU ZION COMMUNICATION CO., LTD can be used in radio frequency coaxial cable, print circuit board, microstrip circuit, etc. it has been proved certain connector of form and certain the cable of the model is matched each other.

   Generally speaking, the fine cable connects with small-sized connector, and yet thick cables corresponding to large size connector. You may see the cable size table attached that introduces how to select the suitable connector.

4. mechanical structure & plating

   Structure of connector affects its price greatly. Different structure requirement meets different occasion. The connector used for military choose the excellent materials. Body of shell use a brass bar or stainless steel bar, the resilient contact use beryllium copper, insulator use Teflon, inner and outer conductor is gold plated, makes more reliable performance. Its resistance is low and anti-corrosive, and the technical requirement of the product is strict. But connector for commercial use More economical material.

   Body of shell use the brass casts the body, insulator use polyethylene, conduct plated silver, etc. Because silver is easy to be oxidized, nicked-plating is more popular. Materials and structure of connector influence working difficulty and efficiency.  

Product Manager : Elsie

Email: elsie@zion-communication.com