Design and preliminary experimental results for a high-frequency crossed electrode phased array, based on a reconfigurable Fresnel lens
Bibliographic record
Abstract
A reconfigurable Fresnel lens approach for 3D imaging on crossed electrode array is described. A Fresnel lens can provide a focus comparable to traditional beamforming if the Fresnel focus is used in one direction, combined with conventional beamforming in the other direction. For example, in azimuth the Fresnel pattern is applied on transmit and dynamic beamforming is completed on receive. A second feature to our crossed electrode design arises from the fact that although a Fresnel lens can create a tight lateral focus, inherently long axial pulses result in poor axial resolution. This is because the phase delays are quantized to 0 or 180 degrees, and at wide steering angles the element path distance spans multiple wavelengths. We have developed a split and delay subaperture technique that maintains axial resolution throughout the image. At 0, 15 and 25 degrees the axial resolution using a single aperture was 64, 180 and 321 um. After splitting the aperture into 8 sub-apertures the resolution is 53, 64 and 77 um. The beamwidths using this technique are comparable to a traditional array and agree well with simulation suggesting that this Fresnel approach shows promise for 3D imaging.
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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 | 0.001 | 0.001 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".