Active Load-pull Measurement System Research Articles

An active millimeter load-pull measurement system using two six-port reflectometers operating in the W-frequency band

An active load-pull measurement system using two six-port reflectometers operating in the W-frequency band is demonstrated. Ninety loads over the whole Smith chart have been synthesized and measured by both reflectometers. The maximum deviation between both measurement data is 0.02 for the magnitude and 3/spl deg/ for the phase of the reflection coefficient of the 90 loads. The constant power gain circles of a PHEMT operating at 89 GHz are shown and compared with those calculated from its S/sub ij/ scattering parameters. The deviation between the radii of circles is less than 0.03.

Model verification for a high-power-efficiency AlGaAs-GaAs HBT

Heterojunction bipolar transistors (HBT's) with 2700 /spl mu/m/sup 2/ of emitter area are characterized for model verification using an active load-pull measurement system. The simulation and measurement results (up to 26 dBm) are reported and compared in terms of output power level and power-added efficiency under variable operating conditions. These measurements are performed with the aim of designing power amplifiers for mobile communications.

Simultaneous AM-AM/AM-PM distortion measurements of microwave transistors using active load-pull and six-port techniques

A programmable active load-pull measurement system using two six-port reflectometers and three passive two-port standards has been developed to obtain load-pull contours of the transistor's input-output phase shift variations over a wide dynamic range of the input power. The output power, gain, power-added efficiency, and phase shift are measured simultaneously at the transistor's input and output reference planes. The phase distortion versus input power, /spl phi//spl sim/P/sub in/, and the AM-PM conversion coefficient at various power levels, k/spl sim/P/sub in/, are obtained for different load impedances by post-measurement calculations. A NE8001 MESFET is tested at f=1.7 GHz for the class A operation. The experimental results are also given.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An automated millimeter-wave active load-pull measurement system based on six-port techniques

A millimeter-wave active load-pull measurement system for large-signal characterization of millimeter-wave transistors is presented. The characterization system uses two six-port junctions for simultaneous impedance and power flow measurements. Large-signal characterization of a GaAs FET operated in class A and class C at 28 GHz in terms of constant absorbed power contours, constant operating power gain contours and constant DC current contours in the load plane Z/sub L/ is presented. Effects of the unilaterality assumption on the operating power gain and output power are investigated for both class A and class C amplifier designs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>