Vector-Receiver Load Pull Measurements

Vector-receiver load pull is a modern and efficient methodology for load pull measurements. Low-loss couplers are placed between the tuners and device-under-test and are connected to a vector receiver such as a VNA. Doing so allows the a- and b-waves to be measured at the DUT reference plane in real-time, presenting vector information not normally made available. Vector-receiver load pull allows the direct measurement of actual impedances presented to the DUT without any assumptions of pre-characterized tuner positioning or losses. The delivered input power is derived from the a- and b-waves with incredible accuracy, which results in properly- defined power added efficiency. Output powers at each frequency, fundamental and multiple harmonics, are made available, as are multi-tone carrier and intermodulation powers. Time-domain NVNA measurements are easily implemented using appropriate hardware (Agilent PNA-X or VTD SWAP).

SOURCE PULL CONVERTER

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Because the a- and b-waves of the DUT are measured at the DUT reference plane, it is possible to measure the large signal input impedance of the device. With this information and through a patent-pending technique, it is possible to simulate the effect of matching the source of the device without having ever varied the source impedance. This "virtual source matching" is highly reliable at even extremely mismatched conditions, and allows for simulated source contours to be drawn. Trade-offs between maximum gain, efficiency and other parameters can be viewed in real-time without multiple source pull load pull iterations.

Typical setup for performing VNA-based load pull measurements using two Maury MT982-series Automated Tuners driven by the Maury IVCAD Advanced Measurement and Modeling Software


Typical vector-receiver load pull block diagram