Difference between RF switch and RF Multiplexer
This page compares RF switch vs RF Multiplexer and describes difference between RF switch and RF Multiplexer with respect to various comparison parameters.
RF switch
The device which switches between different RF paths as per switching configuration is called RF switch. It is used for Tx/Rx switching, automatic routing of RF signals from one path to the other, wireless test and measurement, turn RF signals ON and OFF etc. RF switches are categorized into electro-mechanical type, solid state type and MEMS. Solid state switches are further categorized into PIN diode based, FET based and hybrid type as per their operation.
The common specifications of RF switch are as follows.
• Frequency range
• Characteristic impedance
• Insertion loss
• Return loss
• Isolation
• Switching speed
• Power handling capacity
• Rise time
• Dimension, connectors etc.
Based on architecture, RF switches are of two types viz. absorptive and reflective. Based on mechanical layout, RF switches of two types viz. connectorized and drop-in.
RF switches in higher output modes such as 4x1 or 8x1 is called RF multiplexers. RF switches in lower output modes such as SPST, SPDT and SP3T are called as relays. Refer RF switch application notes , absorptive vs reflective rf switch , electro-mechanical vs solid state rf switch and RF switch selection guide for more information.
RF Multiplexer
RF multiplexer is a RF device which combines multiple RF signals into single port or separates signal from one port to multiple signals on different ports or paths. It is called multiplexer when it combines many signals into one single output. It is called demultiplexer when it separates one signal input to multiple signal outputs. There are various types of multiplexers such as FDM, TDM and CDM. It helps to increase the capacity of a channel to carry data.
It is similar to the RF switch in terms of routing RF signals but uses more number of ports. It allows multiple RF signals to be routed to single port as per filters used in its design.
Example of Multiplexer: with 4 to 1 configuration is shown in the figure. This type of RF multiplexer is called quadplexer.
The other types are RF hexaplexer and RF pentaplexer.
Refer difference between Quadplexer vs Quadruplexer >> and
duplexer vs quadplexer vs hexaplexer vs pentaplexer >> for more information.
For example Keysight M9147A is RF multiplexer which allows routing of 3 GHz signal through any of the four RF switch multiplexers
in single PXI chassi module. The specifications of this RF Multiplexer are as follows.
• Configuration (1 x 4)
• Isolation (50 dB) at 1 GHz
• Insertion loss (1.3 dB) at 3 GHz
➨Conclusion : RF switch is used to switch RF signals across different paths in a system where as RF multiplexer is used to combine multiple RF signals into one RF signal or to segregate one RF signal into multiple RF signals.