Automatic fixture removal option for easy non-coaxial device measurement

May 21, 2014 // By Jean-Pierre Joosting
Agilent Technologies has announced an automatic fixture removal (AFR) option for its PNA Series network analyzers. Previously available only in the company’s Physical Layer Test System (PLTS) software, the error-correction technique claims to be the industry’s fastest, easiest way to accurately measure non-coaxial devices, saving engineers time and money.

Many of today’s devices do not have coaxial connectors and are put in fixtures to measure them in a coaxial environment. However, accurate removal of the fixture’s effects is required to obtain a good measurement of the device-under-test. While EM simulation software modeling or multiple calibration standards fabricated on board can be used to characterize and remove a fixture, such approaches are complicated and time-consuming.

Agilent’s latest AFR option for the PNA provides engineers a faster, more accurate way to remove fixture effects from non-coaxial device measurements. A powerful five-step wizard quickly guides the engineer through the necessary steps. De-embed files can be saved in a variety of formats for later use in PNA, PLTS and Advanced Design System software.

Using the AFR option, the engineer must first calibrate in coax with the reference planes at the inputs to the fixture. Then, one or more standards designed as a replica of the fixture’s 2-port thru or fixture half terminated with an open or short are measured. Even faster fixture de-embedding is possible with one-port AFR. In this case, the actual fixture is measured before the DUT is installed for the open standard. The AFR option then automatically characterizes and removes the fixture from the measurement. This one-port AFR capability is also now available in the PLTS software.

“While the accuracy of our AFR option is comparable to on-board TRL calibration, it is significantly easier to accomplish,” said Steve Scheppelmann, marketing manager of Agilent’s Component Test Division. “For microwave engineers new to AFR, that means they no longer have to perform complicated EM simulations or build on-board calibration kits to accurately correct for fixture effects. Signal integrity engineers already familiar with AFR will also benefit by saving even more time with the option’s one-port capability.”