On-Wafer Vector Network Analyzer Calibration and Measurements

The representative VNA block diagram (see Figure 1) shows the key elements of the analyzer. The RF source at the top provides the device-under-test (DUT) stimulus. A forward/reverse switch directs the RF energy to either DUT port. The test set uses directional couplers or bridges to pick off the forward and reverse waves traveling to and from each port, and down-converts these signals to four IF sections. Each IF section filters, amplifies, and digitizes the signals for further digital processing and display.