On the Double-Inflection Characteristic of the Continuous-Wave AM/AM in Class-F<sup>−1</sup> Power Amplifiers
Bibliographic record
Abstract
This letter investigates the impact of open second-harmonic impedance on the static amplitude-to-amplitude modulation (AM/AM) characteristic of class-F-1power amplifiers (PAs). The phenomenon of double gain compression in harmonically tuned PAs is analyzed for the first time. The study starts with presenting a theoretical postulation explaining the occurrence of inflection points in AM/AM profiles of class-F-1PAs. Thereafter, a simplified mathematical model providing closed-form expressions for predicting the locations of output power levels of the first and second AM/AM inflection points is presented. For practical validation, an active load-pull system is used to synthesize class-F-1load conditions using a 0.7-mm NXP GaN die at a frequency of 2.6 GHz. The gain curve profile varies quite significantly as a function of second harmonic load reactance and it has been measured to capture the AM/AM inflection phenomenon at low power levels. Under class-F-1harmonic loading conditions at 28 and 48 V, the active load-pull measurements demonstrate the phenomenon of AM/AM inflection and agree well with the mathematical analysis presented in this letter.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".