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RF Connectors and Their Types

RF connectors are a type of connector used to transmit radio frequency signals by connecting transmission lines to various applications. In this blog, we will discuss five of the most common types of RF connectors: Bayonet Neill-Concelman (BNC), Subminiature A (SMA), Subminiature B (SMB), N-Type, and Threaded Neill Concelman (TNC). Before we look at RF connectors, it is important to understand how coaxial cables work. For a connector to transmit a radio frequency, there must be a transmission line. Coaxial cables are the most commonly used transmission line, as they have both inner and outer conductors, meaning coaxial cables experience less loss of signal and can be used in close proximity to metal objects without interference.

There are four main parts of a coaxial cable: the outer jacket, metallic shield (which is the outer conductor), dielectric insulator, and the central core (the inner conductor). The space between the inner and outer conductors is the impedance. To prevent signal reflection, the impedance must be the same throughout the entire length of the cable. Additionally, when an RF connector is used at the end of a coaxial cable, the impedances must match, or the signal will not be effectively transmitted. Now, let’s take a look at the main types of RF connectors.

The Bayonet Neill-Concelman, or BNC, is a type of connector with a secure and quick-fastening bayonet mechanism. They are commonly available with either 50 or 75 ohms of impedance and feature a standard frequency of 4 GHz, though higher-quality versions can provide better performance. BNC connectors are commonly used in coaxial cables in radio, television, RF electric equipment, test instruments, and video signals. Subminiature A, or simply SMA connectors, are roughly half the size of a BNC connector. They feature a threaded coupling that provides a highly secure connection. They are available with an impedance of 50 ohms and a frequency limit of GHz. The most common uses of SMA connectors are for RF connectivity between boards, microwave filters, attenuators, mixers, and oscillators.

Subminatire B (SMB) connectors are even smaller than SMA connectors and consist of a snap-on fastening mechanism that allows for rapid mating and unmating. Connectors of this type are so small that they are commonly used for inter board or inter-assembly connections within pieces of equipment. Similar to BNC connectors, SMB connectors are available in 50 or 75-ohm impedances and have a frequency limit of 4 GHz. N-type connectors are ideal for use in applications that require high performance. Like BNC and SMB connectors, N-Type connectors are available in 50 or 75-ohm impedance options and feature a threaded coupling mechanism to help them connect. Although their 11 GHz frequency limit is lower than that of SMA connectors, precise versions can perform at up to 18 GHz.

The final type of RF connector is the Threaded Neill Concelman or TNC. It is a threaded version of the BNC connector and has a 50-ohm impedance and frequency limit of 11 GHz. The bayonet fastening in BNC connectors often creates problems for the transmission of the signal. This problem is eliminated by TNC connectors and they are therefore able to operate at higher frequencies than BNC connectors.

For RF connectors of all types and much more, look no further than NSN Sphere. Owned and operated by ASAP Semiconductor, we can help you find all types of parts for the aerospace, civil aviation, defense, electronics, industrial, and IT hardware markets. Our account managers are always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at 1-714-705-4780. Let us show you why we consider ourselves the future of purchasing.

About Author - Charles Howard

Charles Howard is a passionate aviation enthusiast with over 15 years of experience in the industry. Holding a degree in Aerospace Engineering, Charles has worked with some of the top aerospace companies and has been involved in various groundbreaking projects that have shaped modern aviation.

Currently Charles is leading the content marketing team at NSN Sphere. Charles's passion for writing is matched only by his commitment to delivering value to his readers. His blogs are known for their clarity, creativity, and ability to distill complex topics into easily digestible and enjoyable reads.


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