Anritsu have introduced the VectorStar Broadband ME7828A vector network analyser system that produces dynamic range, measurement speed, and calibration and measurement stability over the broad frequency range of 70kHz to 110GHz. The performance and frequency coverage provide designers and manufacturers of microwave/millimetre wave components and devices with a single system to accurately and quickly measure devices from DC to daylight.
Engineers performing device modelling and characterisation must measure across the widest frequency range possible for optimum model accuracy. During the design phase, they must constantly re-verify their device models through measurement verification. Confirming DC performance at higher frequencies is equally important. Traditionally, users have been constrained by the unreliable performance of microwave VNAs below 500MHz, as signal-to-noise ratio diminishes below 500MHz due to microwave coupler roll-off. The result has been a significant weakness in device models at the low end.
Previously, the only solution was to re-measure the device on a separate low-frequency system that has resulted in large concatenation errors. VectorStar has 70kHz low-end frequency, which makes it possible to accurately measure devices starting at 70kHz for DC information and up to 110GHz for capturing all the performance of the device at multiple fundamental harmonics.
The incorporation of VectorStar produces other performance advantages, including dynamic range improvements of up to 30dB. The ME7828A vector network analyser system also incorporates the fast switching speed of Anritsu’s MG37022A sources to produce a sweep speed of 120m/s for 201 points with four times faster. Combining the broad frequency range with 100,000 points in a single channel, the ME7828A vector network analyser system provides a complete time domain analysis capability.
On-wafer environments require measurement stability because the process of re-calibration is time consuming and expensive. The ME7828A vector network analyser system delivers calibration and measurement stability, typically 0.1dB over a 24-hour period.
Two configurations are available. The standard ME7828A vector network analyser provides basic measurement capabilities for active device testing. The ME7828A-012 vector network analyser delivers additional optimal performance for active device testing, time domain analysis and device characterisation. Both configurations are compatible with existing SUSS and Cascade probe stations and appropriate positioners.
The ME7828A netwrork analyser system can be configured with a full range of banded millimetre-wave modules that extend the frequency range to 500GHz. A variable attenuator in the millimetre band modules for both configurations allows matching power of the two bands for a smooth transition when measuring active devices in the forward and reverse directions.
Kelvin bias tees are designed into the multiplexing combiner modules in both configurations. The Kelvin bias tees provide sense and force capabilities, and are positioned close to the device under test (DUT) for optimum performance and sensitivity. The result is a significant reduction in IR losses compared to bias sourcing from inside the test set. In addition, the sensing circuit continuously monitors the bias conditions at the DUT and provides feedback corrections to the Source Monitor Unit (SMU) bias supply equipment, as needed.