More about RF terminations and RF Loads
RF Terminations or loads are components that are used to absorb energy and prevent RF signals from reflecting back from an open-ended or unused port. The ports are usually terminated with a load that has the same characteristic impedance as the transmission line. Any multi-port RF system, whose ports are not all being used should be terminated so that any signal incident on these ports will be absorbed. If a port is left un-terminated, then the signals can reflect back into the system which can introduce distortions and other undesirable effects. These are used in couplers, hybrids, isolators, test equipment and in systems where a port needs to be terminated. There are three main types of RF terminations: coaxial, waveguide, and chip. Coaxial terminations terminate coaxial ports, and waveguide terminations terminate waveguide ports. Chip terminations have integrated circuit (IC) chip terminations.
Selecting RF Terminations
When selecting an RF termination it is important to know the parameters that you need to specify. Below are a list of the key parameters to look out for when selecting a termination:
Impedance: This is the most important characteristic of a termination. This is the characteristic impedance of the port that needs to be terminated. The impedance value of the termination must match the characteristic impedance of the port being terminated. 50 Ohm terminations are the most common, followed by 75 Ohms and then custom values based on the system requirement.
Power (W): This is the power level that can be adsorbed by the termination while maintaining its electrical characteristic.
VSWR: VSWR is a unit-less ratio that defines the amount of power reflected by the termination. A value of 1:1 indicates that 100% of the incident energy is absorbed by the load or there is no reflected energy. Any other value indicates that a portion of the energy is reflected.
Return loss (dB): Return loss also measures the amount of power reflected by the termination. Better put, it is a measure of the match between the impedance of the RF terminations and the impedance of the system. A higher return loss is desirable in an electronic circuit. Click here to learn more about return loss.
Package Type: Terminations are available in surface mount, connectorized, and waveguide form factor. When it is connecterized, then the type of connector must also be specified. Connector types include: SMA, BNC, N Type etc.
everything RF lists RF Terminations from leading manufacturers. Use the parametric search tools to narrow down on products based on your requirement. Once you find parts that meet your specification, download the data sheet, compare products and request quotations. Inquiries sent via everything RF are directed to the manufacturers who get back to you with a quote or information.
