RF Test Equipment Series: Matrix Switches and Switch Matrices

Matrix Switches, or Switch Matrices, are devices that enable the routing of RF signals through selectable paths. These devices can be as simple as single-input with two selectable outputs or as complex as having tens of inputs and outputs that can all be interested as needed. Switch Matrices are often used in test equipment setups that require multiple pieces of test equipment and while testing complex DUTs, such as radios, handsets, amplifiers, etc. Switch Matrices can be controlled my simple analog voltage inputs, mechanical switches, digital inputs, or even with more sophisticated software control.

Important Matrix Switch/Switch Matrix Performance Parameters

• Insertion Loss
• Maximum Power Handling
• Isolation (between input and output channels and from input and outputs)
• Operating Frequency and Bandwidth
• Group Delay
• VSWR at each state
• Control Signal type and functional parameters
• Linearity
• Noise floor

Uses of Switch Matrices/Matrix Switches

• Allow for various interconnect options from one or more input ports to one or more output ports
• Enable control (digital, analog, software) of attenuators, phase shifters, delay lines, filters, generators, and receivers
• Operate as a variable interconnect mechanism between test equipment (network analyzers, spectrum analyzers, signal generators, sources, receivers, and DUTs)
• Control antenna array behavior, such as beamforming
• As a fail-safe or backup option for switchable redundancy applications
• Antenna duplexing
• As part of a modulation circuit for amplitude modulation (AM), phase modulation (PM), and frequency modulation (FM)

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Source: Wikipedia

RF Switch Types

• Single-pole Single-throw (SPST)
• Double-pole Single-throw (DPST)
• Single-pole Double-throw (SPDT)
• Double-pole Double-throw (DPDT)
• Multi-pole Multi-throw (#P#T)
• Rotary Transfer Switch

RF Switch Matrices are often sold as stand-alone pieces of test and measurement equipment, integrated into assemblies, or sold as discrete devices built into RF systems. Hence, there are many custom varieties with various interconnect standards and other operational parameters. In the case of Switch Matrices designed as test equipment, they are often shipped with the appropriate coaxial or waveguide connectors for their intended frequency range of operation. As Switch Matrices are used alongside many other forms of test equipment, they require precision interconnect, such as adapters, coaxial cables, waveguide, and often require phase stable and skew matched cable combinations to eliminate the variations between channels.

Useful Matrix Switch and Switch Matrices Accessories and Equipment

• Pasternack VNA Calibration Kits
• Pasternack Phase Stable (VNA) Coaxial Cables
• Pasternack Cable Generic Test Cable Assemblies
• Pasternack Skew Matched Pair Coaxial Cable
• Pasternack Precision Coaxial Adapters
• Pasternack In-series and Between-series Adapters
• Pasternack RF Coaxial Probe