The software features powerful data-acquisition and processing capabilities. The data-acquisition setup table features simple, straightforward data entry for naming the data, defining the instrument state for the VNA, setting the measurement ports and switches, setting any time out after a measurement, and adding error correction (Fig. 4). Data can be shown in tabular or graphical formats, with the data-acquisition functions emulating the flexibility of the software’s port-naming capabilities. A simple data-processing setup table allows operators to provide names for different measured parameters, along with units of measure, the source of the data, the S-parameters used, the post-processing function applied, any limits for the test, and the scales for plotted curves (Fig. 5). Armed with measurement results, an operator can also define the parameters by which a DUT passes or fails a set of tests, using a data summary with user-defined parameter names to quickly show the performance of the device (Fig. 6).

Once data has been acquired, the software’s post-processing capabilities allow an operator to select any of the captured data and show it in any number of different formats. For example, the software can perform postprocessing on captured S-parameter data and create plots of group delay, insertion loss versus frequency, and even deviation from linear phase to simplify analysis (Fig. 7).

The software is flexible enough in its post-processing capabilities that virtually any form of standard or custom tabular or plotted presentation can be created. Plots can be created by comparing, combining, or subtracting sets of data; even smoothing functions according to operator-defined percentages are possible. Operators can draw from a standard library of plotting functions and then add their own custom scripts to the plots, or add specific DUT parameters to generate plots for functions that aren’t currently in the standard library, and save those plotting functions for future use.

The post-processing capabilities of this powerful PC software provide real-time feedback about a DUT’s electrical performance, making it possible to quickly ascertain whether a complex assembly meets its specified requirements. Prior to having this level of data acquisition and post-processing automation, data would be acquired manually with a microwave VNA and formatted in an Excel spreadsheet according to the desired display function. As with the many measurements on a complex multiport DUT, this approach to data processing is cumbersome and time consuming.

The multiport measurement software can automatically recalculate a function or set of functions, such as port-to-port insertion loss and return loss, with every measurement acquisition. Using the test system’s integral thermal plate, for example, allows an operator to track the performance of a multiport DUT as a function of temperature in real time, simplifying the analysis of performance behavior with temperature changes and over the operating temperature range.

The software provides enough flexibility and capability to coordinate the many functions needed for accurate VNA measurements on a high-port-count DUT. As the software is orchestrating the VNA for the desired set of measurements and acquiring data, it is also automatically controlling the electromechanical switch matrix. In addition, it is uploading error-correction files saved during the initial system calibration and applying these to the VNA so that the system is properly calibrated and corrected for each measurement. The software also supports a “tuning mode,” which allows a user to select specific groups of data at specific measurement points, such as between two ports in a multiport DUT. Rather than sweeping across a measurement frequency range, in tuning mode the operator can focus on a single port and even on a single frequency or set of frequencies for tuning purposes, making adjustments, for example, by turning a screw rotor on a trimmer capacitor until the DUT meets its specifications at a given frequency or set of frequencies.

The tuning mode is fully configurable and allows operators to view multiple graphs on a PC’s monitor (Fig. 8) according to the post-processing data selected by the operator. For example, four plots can be shown simultaneously in tuning mode, for four different parameters or even for the same parameter as a function of time, comparing historical results to current performance following tuning.

The software supports saving data in Excel spreadsheet files, allowing operators to create customized reports (Fig. 9). This occurs automatically and unseen by the operator, with any set of post-processing data saved within a given range in an Excel file. As more measurements are made and data within those specified ranges are updated, so are the Excel files. The data can also be saved into tables with the same automatic update operation. An operator simply creates a template for the data in an Excel file, creating areas within the file called “range names” that contain the cells or blocks of cells used to hold post-processed data from the VNA. The system then automatically writes post-processed data into these cells or groups of cells. An unlimited number of templates can be created in order to display data in many different formats and in different units.

For testing large multiport modules, the alternative to this system involves the design of custom signalswitching hardware to route test signals to the appropriate ports on the DUT, and writing custom software for control of the test hardware, data acquisition, and post processing of the measurement data. The In-Phase Technologies multiport test system can be configured to a customer’s specific DUT requirements and bundled as a hardware and software solution or as an “upgrade” to a customer’s own microwave VNA system. For more information about how the system can meet specific requirements, contact the factory.