Rohde & Schwarz demonstrated new capabilities for evaluating differential (balanced) devices at the International Microwave Symposium. Rohde & Schwarz R&S ZVA and R&S ZVT series of vector network analyzers (VNA) equipped with the R&S ZVA-K6 true differential option can now take advantage of the coherent signal sources to adjust them to a selected phase or amplitude offset. This unique capability, made possible by a special architecture, is valuable when characterizing phased-array antennas, the nonlinear behavior of differential amplifiers and many other applications for aerospace and defense.

The VNAs of the R&S ZVA and R&S ZVT series are based on a true multiport architecture, with independent sources per port pair. This offers significantly higher accuracy, dynamic range and measurement speed compared to the use of switch matrices when evaluating devices with multiple ports.

The four coherent sources in the R&S ZVT8 VNA can be used for example to stimulate four antennas of a phased antenna array with defined phase or magnitude offsets. The 16 receivers of the R&S ZVT8 can be used to measure the magnitude and phase relationships between the output signals of up to 16 antennas in real time.

The R&S ZVA-K6 option also solves the problem faced by designers who had to measure active differential devices close or in compression. To get reliable results in the DUT’s nonlinear region, R&S ZVA or R&S ZVT stimulates it with true differential signals, that means both sources have a phase offset of exactly 180° in the measurement plane. The R&S ZVA-K6 option was the first solution for accurate and fast characterization of balanced devices under large-signal conditions. It helps designers and manufacturers of power transistors, amplifiers, MMICs, RFICs and other active differential devices to precisely characterize their products.