- Buyers Guide
Agilent Technologies Inc. introduced a new option -- arbitrary load impedance X-parameters -- for its PNA-X Nonlinear Vector Network Analyzer. The option, when used in conjunction with Maury Microwave tuners and software, enables the industry's first capability to accurately measure and simulate nonlinear component behavior at all load impedances. The result is the highest level of insight into nonlinear DUT behavior, making the NVNA capability especially useful for scientists researching new RF technologies and engineers involved in designing today's high-performance active devices.
The addition of the arbitrary load impedance X-parameter option to the PNA-X nonlinear vector network analyzer allows R&D engineers in the wireless communications and aerospace/defense industries to:
• Extend X-parameter design "cascade-ability" to arbitrarily large load mismatches. By removing the constraint for the output match to be either small or moderate, engineers can now measure and simulate accurate, linear and nonlinear behavior over a load gamma range covering the full Smith chart. Inter-stage matching of components with varying impedances is now fully predictable in the simulator.
• Measure and predict dynamic load-lines at input and output ports under arbitrary loading conditions, even under very large compression.
• Measure and simulate magnitude and phase data at the input and output for each fundamental and harmonic frequency as nonlinear functions of power, bias and now arbitrary load impedance. The resulting data can be used for simulation in ADS.
• Model devices and design multistage, Doherty or other complex amplifier circuits with the drag-and-drop simplicity of Agilent's Advanced Design System (ADS). Because the PNA-X nonlinear vector network analyzer creates ADS compatible models, engineers need simply drag and drop models into ADS for circuit simulation, enabling fast and efficient design of active RF components like power amplifiers.
A key benefit of the arbitrary load impedance X-parameter option is that it allows the engineer to see how all signals react with their device. This takes the guesswork out of the typical "trial and error" design approach and by minimizing design iteration, reduces the overall design cycle by 50 percent. In one real-world example, a GSM power amplifier designer was able to reduce test times from one month to one day. Since engineers no longer have to "over design" to safeguard against potential errors, design costs are also minimized.
Agilent's PNA-X nonlinear vector network analyzer was introduced in 2008 and is the industry's first measurement and simulation environment for designing nonlinear components. It enables characterization of a device's nonlinear behavior with the highest level of accuracy, speed and ease-of-use in the industry. The PNA-X nonlinear vector network analyzer, X-parameters and ADS can be used to deterministically design multistage components and systems under varying interstage match conditions, reconstruct time domain waveforms and optimize performance parameters such as ACPR, EVM and PAE, as well as nonlinear system performance.
X-parameters are mathematically correct scattering coefficients for active components. They provide a powerful, yet simple and automated process for capturing nonlinear component behavior over arbitrary complex impedances, input powers, DC biases, and more across various frequencies. Using the PNA-X nonlinear vector network analyzer, X-parameters are measured and used to create X-parameter models that can be imported into Agilent's (ADS) to simulate actual linear and nonlinear component behavior. The full complex Gamma dependence of a device under large-signal operating conditions can now be captured and instantly modeled in ADS using Agilent's new NVNA option, an external Maury load tuner, and Maury's load-pull software.
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