How to choose RF connector
There are a wide variety of RF connectors, and it is important for the design engineer to choose the right RF connector to ensure the reliability of the whole machine or the entire system is more important, or more convenient and practical. In the work practice, according to your own needs to choose the right RF connector, you can consider the following convenient factors:
First, the electrical performance of the product
1, characteristic impedance
The characteristic impedance of the RF connector is 50Ω and 75Ω. Many series of connectors are available in 50Ω and 75Ω. Generally, 50Ω connectors are used in high-frequency, high-performance products; 75Ω connectors are more frequently used. Low products, the frequency is mostly below 4GHz, especially in consumer electronic video. Users should choose the connector that matches their impedance according to their product. If the user is using a 75Ω RG59 cable, the 75Ω connector should be selected.
Each RF connector has a frequency range. Users need to know the operating frequency of their products to select a connector. Selecting a connector lower than the required operating frequency will affect the electrical performance of the whole machine. Or choose expensive high-precision high-frequency. The connector is wasted. It should be noted that the frequency of use of connectors designed by different companies is relatively large, and the frequency of inferior products is far from meeting the industry requirements. When selecting a connector, the user should confirm the electrical performance of the product.
VSWR is one of the most important performance indicators of RF connectors. It is a measure of the amount of return of a metering signal from a connector. It is a vector unit including amplitude and phase components. The VSWR of the same type of connector is different at different frequencies of use. In general, the higher the frequency of use, the higher the VSWR. If the user wants to know the VWSR at a particular frequency of the connector, the manufacturer can be queried.
Second, the connector is inserted
As shown in Figure 1, the type of snap-in configuration
The main feature of the snap-in type connector connector is that the connector can be locked by rotating 90 degrees, and the connection speed is fast and stable. Suitable for frequent loading and unloading equipment, widely used in network systems, instrumentation and other fields. BNC series is a typical bayonet connector.
2, embedded configuration type
The push-in interface features quick connection and separation, small size and light weight. It is mostly used for board-to-board connection inside the cabinet and high-density mounting. Common push-in connectors are SMB, MCX, MMCX, etc.
3, thread type structure type
The threaded interface is characterized by the most reliable connection, high mechanical strength and good vibration resistance. Due to the mechanical properties of electrical appliances, many of them are used in the test aircraft, military aviation field. Commonly used threaded connectors are SMA, N, 7 / 16, 2.92, etc.
4, slide-in type structure
The slide-in type of plug-in structure is widely used in applications requiring compact structure and easy operation. BMA connectors and D-Sub connectors are used in the type of slide-in type.
Third, the termination form
The same series of connectors also have different termination forms
Wiring is divided into wire bond and crimp connectors. Wire bonding is the welding center conductor and cable shield. The crimping type is to crimp the center conductor and the cable shielding layer, and the pressing type efficiency is good. The wire bonding type is stable and reliable.
Generally, flexible cables are mostly crimped, and semi-flexible cables are mostly welded.
When the connector is to be connected to the PCB, it is mostly plug-in or patch type. In order to accommodate the tin, the metal connected to the PCB is mostly gold plated or tin plated.
3, panel type
Panel connectors are mostly mounted on the chassis to connect internal and external equipment. The flange type is drilled and fixed on the panel of the connector body. Another type is to screw the thread on the connector body and fix it with a screw. Such connectors are often also required to be waterproof.
Fourth, mechanical structure, material, surface treatment
Mechanical structure, material, and surface treatment have a great impact on the performance and price of the connector. The mechanical structure determines the production efficiency and materials, and even the materials. Common materials for connectors are brass, bronze, beryllium copper, stainless steel, and PTFE. Brass and bronze are relatively low in price, low in hardness, easy to process, and highly productive. Beryllium copper, stainless steel is high in price, high in hardness and good in elasticity, but it is difficult to process. The RF connector is used for reducing the resistivity and obtaining excellent corrosion resistance and oxidation resistance for precious metal plating such as gold, silver, nickel, and the like. In particular, small conductors with a small size have a greater impact on performance. Due to the high price of these metals, the price has a great impact, and the general manufacturers specify the plating thickness in the specification.
Tiankele reminds users to choose the RF connector with reasonable environment and high cost performance according to the above factors.
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