RF Isolator Selection Guide | RF Isolator specifications

This page covers RF Isolator selection guide and technical specifications. It mentions RF Isolator specifications one need to consider while selecting or buying RF Isolator for their need.

The isolator is a two port device which forwards the signal only in one direction and blocks the signal in the other direction. This is depicted in the figure-1 below. Signal can travel from port-1 to the port-2 without much interruption. The instrument or device connected at port-1 will not have any reflections originating from port-2.

RF Isolator selection guide

rf isolator function

Following guidelines should be followed while selecting RF Circulator as per your need.
➤Frequency range over which isolator can be used.
➤Isolation should be as high as possible (from port-2 to port-1).
➤Insertion loss should be as low as possible.
➤VSWR is measured as ratio. Lower the ratio is better for isolator to be used.
➤The other parameters are mechanical such as isolator size, packege type (drop-in, connectorized), connectors at ports etc.
➤Refer table-1 below which mentions other specifications of the RF isolator while selecting one for your need.

RF Isolator Specifications

Following table mentions technical specifications of an RF Isolator.

RF Isolator Specifications Description
Frequency range The figure indicates range of frequencies over which RF isolator is useful.
Insertion Loss It indicates how much energy is lost during signal transfer from input port-1 to the output port-2. This should be as minimum as possible.
It is expressed by 10*Log10(P2/P1)
Isolation It is the measure of how well isolation (or decoupling) is carried out from output port-2 to input port-1. This should be as high as possible. It has typical value of about 20 to 25 dB.
VSWR It stands for Voltage Standing Wave Ratio. It is the ratio of maximum voltage to the minimum voltage created due to imperfect impedance mismatch when two boundaries meet. The VSWR with 1.1:1 is better compare to 1.3:1 and so on.
Power Handling It is measure of how much power isolator can handle without degrading its performance.
Group Delay The time duration signal takes from entering at input port-1 to come out at output port-2. It is expressed in units of picoseconds or nanoseconds.
Package Type • Drop-in package
• Surface mount package
• Connectorized package
Type of connectors SMA, Coaxial N-type etc.

RF Isolator Related Links

What is RF Isolator
RF Isolator Manufacturers
Difference between RF Isolator and RF Circulator
How RF Isolator Works
RF Isolator Selection Guide
RF Isolator Application Notes

RF and Wireless Terminologies