It’s that time of year again for the IEEE MTT-S International Microwave Symposium (IMS). Here’s a...
Looking for a Practical Guide to Load Pull Measurements? Download our eBook
The eBook, "A Practical Guide to Load Pull Measurements," is a comprehensive resource featuring a curated collection of articles and papers spanning several years. In addition to an overview of load pull applications, this blog post provides readers with a sneak peek at the content, covering everything from fundamental concepts to advanced load pull measurement techniques.
Load Pull Applications
Testing, measuring, and characterizing device behavior is critical for RF and microwave engineering to analyze and optimize performance, validate designs, troubleshoot system faults, and meet specifications. Scattering parameters (S-parameters) are valid for small-signal analysis, assessing RF and microwave device under test (DUT) behavior that approximates as linear. Engineers can use S-parameters to understand a network’s signal propagation characteristics, such as reflection and transmission properties, to implement design improvements effectively.
Large-signal nonlinear operating conditions, which can include factors such as intermodulation distortion (IMD) products and harmonics, require testing beyond S-parameters – a level of characterization achieved by load pull measurements. Load pull involves varying the load impedance to a DUT to observe its response and determine the parameters that enable the highest level of performance. Used in various applications, some primary load pull use-cases include:
Engineers can identify and evaluate transistor performance across power, efficiency, gain, and linearity, among others, as a function of load impedance.
By stress testing compact transistor models via load pull, designers can compare predicted behavior with actual load pull-based results for model refinement or validation.
Behavioral models outline a DUT’s responses to a set of stimuli. Load pull enhances behavioral model robustness by providing critical data about a device’s response to various impedance conditions.
Determining ideal impedances to achieve desired characteristics, such as maximizing output power or minimizing distortion, better informs the design of a matching network to ensure peak performance.
How will a device perform in challenging operating environments? Subjecting DUTs to diverse conditions and stress levels, such as different load impedances, can help identify faults, limitations, and design alterations that improve reliability.
Depending on the use-case, engineers can employ various load pull technologies and techniques, including passive scalar, harmonic, passive vector-receiver, active, hybrid-active, and mixed-signal active load pull. This eBook dives into these different load pull methods, outlining essential concepts, applications, measurement system setups, and the advantage load pull brings to the design of RF and microwave systems.
eBook Content Highlights
Readers will first learn load pull fundamentals and measurement techniques in “A Beginner’s Guide to All Things Load Pull (or Impedance Tuning 101)” on page 4 and “Tracing the Evolution of Load-Pull Methods” on page 9.
“Vector-Receiver Load Pull Measurement,” an article featured on page 14, takes a deeper dive into vector- receiver load pull systems, comparing its features and characteristics with more traditional load pull test setups.
What is harmonic impedance matching? What are some modern harmonic load pull techniques? Why should amplifier designers take note? Uncover the answers in the page 20 article, “Understanding the Relevance of Harmonic Impedance Matching in Amplifier Design.” Page 27 includes even more critical test considerations for amplifier designers, reviewing mixed-signal active load pull techniques to extend the capabilities of traditional active load-pull systems.
Page 36 and page 42 discuss different methods to achieve on-wafer load pull measurements at millimeter wave (mmWave) frequencies to support the development of 5G technologies. High-frequency applications continue in the page 48 article, “On-Wafer, Large-Signal Transistor Characterization from 70–110 GHz Using an Optimized Load-Pull Technique,” which focuses on how to optimize circuit design for systems operating in the upper mmWave bands of 70 GHz to 110 GHz with load pull characterization.
The continued evolution of semiconductor technologies drives applications into the sub-THz frequency spectrum. Explore power control, power sweeps, and load pull test setups for sub-THz applications in the article, “Frequency Scalable, Power Control and Active Tuning for Sub-THz Large-Signal Measurements,” on page 53 and “Millimeter Wave and Sub-THz Power Sweep and Active Load-Pull Measurements” on page 60.
With this resource, get ready to strengthen your load pull knowledge and elevate your wireless designs. Download the eBook today by filling out the form below.
