Basic knowledge of RF connectors

The radio frequency connector is defined as a separable component that is usually installed on a cable or device for electrical connection of a transmission line system. It can be seen from this definition that it has the common feature of the "detachable element" connector. "Transmission line system" refers to the microwave transmission system. The common structure of transmission line is shown in the figure below:

Signal transmission principle

Take the commonly used coaxial line as an example, the main mode of the coaxial line is TEM wave, and the field distribution is shown in the figure below:

The electromagnetic wave transmitted is an oscillating particle wave derived from the same phase and perpendicular electric field and magnetic field in space. It is an electromagnetic field propagating in the form of wave and has wave-particle duality.

Electromagnetic waves move in the form of waves by electric and magnetic fields that oscillate in phase and are perpendicular to each other. The electric field direction, magnetic field direction, and propagation direction of electromagnetic waves are perpendicular to each other. Electromagnetic waves have no longitudinal components and are transverse electromagnetic waves.

Classification and main technical parameters

RF connectors are mainly divided into three categories: RF coaxial connectors, RF triaxial connectors and dual-core symmetrical RF connectors. The main uses are as follows:

1. RF coaxial connector: mainly used to transmit transverse electromagnetic waves (TEM waves);
2. Radio frequency triaxial connector: mainly used in occasions with higher requirements for shielding efficiency, to transmit transverse electromagnetic waves (TEM waves) or transmit pulse waves;
3. Dual-core symmetrical radio frequency connector: mainly used to transmit digital signals with a low speed.

The main performance parameters of radio frequency coaxial connectors

Including characteristic impedance, operating frequency, return loss, insertion loss, isolation, radio frequency leakage, phase consistency, third-order intermodulation, etc.

Commonly used materials and coatings for RF coaxial connectors

The radio frequency connector is mainly composed of outer conductor, inner conductor and insulating support medium and other parts. The commonly used materials are as follows:

1. Outer conductor: stainless steel passivation, copper alloy gold plating, copper alloy nickel plating, copper alloy plating ternary alloy, etc.;
2. Inner conductor: copper alloy plated with gold, copper alloy plated with silver, etc.;
3. Insulation support medium: PTFE, PEI, LCP, etc.

Elecbee is an electronic conponents store online, and we provide retail and customized services. We provide more than 30 kinds of RF connector products, such as SMA, SSMA, BMA, SBMA, SMP, SMPM, N, TNC, 2.92, 2.4, 1.85 and other products.

The maximum operating frequency of the product reaches 65GHz. The first sample of the 1.0 series millimeter wave connector with a working frequency of 110 GHz has been successfully developed. It is the first to introduce the L7 series radio frequency coaxial connector with a characteristic impedance of 75Ω and an operating frequency of 6GHz to meet the new needs of the military and civilian products. Products are widely used in weapons and equipment, communications, rail transit and medical fields.

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