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Application Note # 51
Application Guide to RF Coaxial Connectors and Cables
By: Michael J. Hannon Product Applications Engineer and Pat Malloy, Sr. Applications Engineer
There is a wide variety of coaxial connectors and cables available for use in the RF and Microwave
While often not much thought is given to these essential components, a misstep here can
result in undesirable system degradation.
Given that typical RF systems are comprised of any number of
items, e.g. RF generators, amplifiers, attenuators, power meters, couplers, antennas, etc., it is not
uncommon that a great deal of thought is given to these “high end” devices while mundane items such as
connectors and cables are often treated as an “afterthought”.
RF coaxial connectors
RF coaxial connectors provide vital RF links in communications, broadcast, EMC testing, commercial
and military, as well as test and measurement fields.
While there is a vast array of RF connectors
available, they are all characterized by just a few key parameters.
The most obvious characteristic of a
connector is its physical size.
Other considerations include power handling and frequency range
To insure maximum power transfer, the characteristic impedance of the connector should
match the source and load.
All of these characteristics along with connector durability and cost must be
considered in light of the specific application.
This application note provides guidance and insight in
choosing connectors best suited to accommodate your specific application.
Let’s begin by reviewing the most commonly found connector types in RF applications.
“traditional” connectors are available in both male and female configurations, standard and precision
grades, high frequency and in some cases high power versions.
The BNC connector is perhaps one of the most widely used connectors in the test
and measurement field. It was developed by Bell Labs in the early 1950’s and is
most commonly found on oscilloscopes, receivers, analyzers and similar lab test
equipment. It is typically used for low power interconnections on RF test
equipment such as audio and signal generators, oscilloscopes and amplifiers.
inexpensive BNC utilizes a bayonet retention collar to provide quick mate/de-mate action and also serves
to prevent accidental disconnection. The BNC connector is typically designed to provide a characteristic
impedance of 50 or 75 ohms, depending on the application.
BNC connectors are generally rated for use
in the DC-4GHz frequency range; however, they are rarely used above 500MHz.
While they are capable
of handling 80-100 Watts average power up to 1GHz, they typically do not have a maximum power rating
but carry a maximum voltage rating of about 500V.