A Scalable Large-Array M-QAM Direct-RF Transmitter Topology With Integrated Physical Layer Security—A Proof of Concept
Bibliographic record
Abstract
This article introduces a transmitter (TX) array topology that employs QPSK direct-RF TX units for realizing scalable large-array wireless communication and multifunction systems. By leveraging spatial power combination, the TX units are set to synthesize an extended M-QAM constellation, enabling flexible and high-order modulation. The QPSK modulation, when transmitted in an array, bolsters physical layer security by confining the constellation retrieval to the intended radiation angle, exhibiting high selectivity. Additionally, its low-dynamic-range (DR) waveform supports high-power output and improves the efficiency of power amplifiers (PAs) compared to higher-order constellations, thus significantly enhancing the array’s overall power–performance ratio. A comprehensive analysis is conducted on key performance factors, including location-dependent antenna gain variations, beamforming effectiveness, and phase front flatness. To validate the proposed technique, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 4$</tex-math> </inline-formula> array proof-of-concept (PoC) implementation is presented. Measurement results demonstrate robust performance across modulation orders ranging from 16-QAM to 256-QAM, aligning with theoretical predictions. This topology effectively integrates spatial constellation formation with the requirements of large-array systems, offering superior power efficiency. Its scalable building blocks, reconfigurability, and inherent secure communication capabilities make it a strong candidate for next-generation high-data-rate large-array TX systems.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".