Application of the Reflective Spiral Photonic Crystal-Delay Line in Beamforming for Phased Array Antennas
Bibliographic record
Abstract
Beam-squint is the primary disadvantage when using conventional phase shifters in the beamforming network of phased array antennas. True time delay lines (TTD) enable squint-free beamforming, since the produced delay is independent of the microwave carrier frequency. Amongst all TTDs, optical delay lines (ODL) possess the highest bandwidth and have strong potential for use in the ultra-wideband systems. Recently, many works have been reported on design and fabrication of photonic crystal delay lines. All of these works, however, have based their delay lines on one dimensional photonic crystal (PC) structures. Therefore achieving longer time delays requires increasing the device size. The objective of this paper is to design a miniaturized TTD which can be used in beamforming network for wideband phased array systems. We propose a novel structure for TTD using total reflection of light in the blocked photonic crystal waveguides (PCW). This novel structure will be referred to here as reflective spiral. It is demonstrated that replacing PCW channels with coupled defects increases the time delay significantly. Using full-wave analysis, it is demonstrated that time delays longer than 8.75 ps can be achieved in a device size less than 20 mum which is 130 times shorter than the required straight distance in free space. The bandwidth of the proposed delay line is more than 2.3 THz.
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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 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".