Wideband cryogenic LNA design for the ngVLA band-1 receiver
Bibliographic record
Abstract
The next-generation Very Large Array (ngVLA) front end incorporates six dual-polarization receivers covering the frequency range from 1.2 to 116 GHz. The ngVLA Band-1 receiver covers a frequency range of 1.2 to 3.5 GHz. This wideband requirement presents a challenge for the extremely low noise design for the required cryogenic low noise amplifier (LNA). GaAs HEMT technology is very reliable at a gate length of 150 nm and that gate feature size is suitable for low noise amplifiers up to the microwave frequency range. Below 3 GHz, the transistor gate has a very large capacitive impedance, exhibiting like an open circuit, which requires large values of inductors for 50 Ω impedance and low noise matching. The hybrid circuit configuration allows the design to select high-Q discrete inductors and capacitors with large values to minimize loss/noise from passive components. A two-stage single-ended GaAs HEMT LNA was designed based on the hybrid configuration. A prototype ngVLA Band-1 LNA was assembled and fully tested at a physical temperature 12 K. This newly designed GaAs HEMT LNA achieved 1.6 K average noise temperature and 34 dB average high gain between 1.2 and 3.5 GHz, the total power consumption is about 10 mW, which can meet the current requirements of the ngVLA Band-1 receiver.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.003 |
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".