Microwave switch system aids HF testing

Keithley Instruments' Model S46 microwave switch system is the first system of this type that can be ordered in a wide variety of configurations for off-the-shelf delivery.

Keithley Instruments' Model S46 microwave switch system is the first system of this type that can be ordered in a wide variety of configurations for off-the-shelf delivery.

Systems can be built with up to eight SPDT coaxial microwave relays and up to four multipole relays.

Any of the multipole relays can be specified as either SP3T, SP4T, SP5T, or SP6T.

These relays can be connected to create switching systems that are configured as multiplexers, matrices, independent relays or any combination that meets users' needs.

For added versatility, coaxial relay connections are provided on the front panel and the physical position of each relay can be specified by the customer.

Moreover, as test requirements change, relays can be easily changed or added to the system to create a new switch configuration.

The resulting 19in rack package comes in a mounting height as low as 2U.

The Model S46 also has exclusive maintenance features that ensure maximum up-time and high quality performance.

These features include a controller that counts and stores the number of closures for every relay contact.

Maintenance personnel can quickly recall this data to determine when relays are nearing the end of their mechanical life.

This allows relay replacement during scheduled maintenance periods, thereby avoiding unplanned shutdowns and loss of production.

Another feature is front panel LEDs that continuously indicate the active channels (closed contacts), which simplifies troubleshooting.

The Model S46 has additional memory available to store "S" parameters (reflection and transmission coefficients) for each signal path, or calibration constants for relay contacts, and even specific performance parameters, such as VSWR and insertion loss.

These parameters can be viewed for trend analysis between scheduled maintenance shutdowns, or used for compensation to enhance accuracy during RF measurements.

The Model S46 is controlled over an IEEE-488 interface bus, so a minimal set of SCPI instructions are needed to operate the 32 control channels.

This simplified instruction set, along with front panel LEDs, shortens startup and debugging time to quickly get the system "up and running".

For application needs beyond the standard Model S46 options, Keithley will design and build customised systems with active and passive RF components as well as relays.

These customised designs incorporate the industry's best coaxial microwave relays, resulting in the lowest insertion loss, VSWR, and crosstalk performance (up to 18GHz for the standard options, or up to 40GHz for customised designs).

To further maximise signal integrity, Keithley offers low loss, semis-flexible RF cables as external connection accessories.

Physical layouts of front and rear panels are built to customer specifications.

Typical product testing applications for the Model S46 include telecommunications devices, cellular basestations, wireless computer peripherals, RF components, and high-speed digital circuits.

OEMs who are building high-frequency test systems can eliminate much design work and shorten time to market by partnering with Keithley on a Model S46 as a subsystem.

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