True-Time-Delay Unit Cell for Ultra-Wideband Single- and Wideband Dual-Polarized Large Reflectarrays
Bibliographic record
Abstract
This paper presents the design and experimental validation of novel ultra-wideband true-time-delay (TTD) reflectarray unit cells for large-scale antenna applications. Two configurations are proposed: a single-polarized unit cell and a dual-polarized unit cell, both utilizing aperture-coupled stacked microstrip circular patches. The single-polarized unit cell employs a parasitic patch, an hourglass-shaped aperture, and a fork-shaped delay line, achieving a linear phase range exceeding 1040° at 13.1 GHz with a phase error below 25° and a linear phase bandwidth of 53% (9.6–16.6 GHz). A reflectarray prototype demonstrates a 3-dB gain bandwidth of 44.4% (10.5–16.5 GHz), with cross-polarization below -30 dB, sidelobe levels better than −13.5 dB, and aperture efficiency up to 55%. The dual-polarized unit cell incorporates perpendicular bowtie-shaped apertures with fork-shaped feeds, enabling independent phase control for both polarizations with a phase range over 1140° at 12.6 GHz, a phase error below 40°, and a linear phase bandwidth of 32% (10.7–14.5 GHz). A dual-polarized reflectarray achieves a 3-dB gain bandwidth of 36.1%, maximum gains of 32 dBi and 31.75 dBi for orthogonal polarizations, cross-polarization below −26 dB, sidelobe levels below −13 dB, and aperture efficiency up to 50%. Both designs exhibit low loss, stable beam direction, and high scalability, significantly advancing wideband reflectarray performance for satellite and communication systems.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".