Polarisation reconfigurable, centre‐fed, and low‐profile Archimedean spiral antennas with unidirectional broadside patterns
Bibliographic record
Abstract
A low‐profile, dual circularly polarised, and centre‐fed four‐arm Archimedean spiral antenna with broadside radiation patterns is investigated in this paper. It is shown that both right‐ and left‐hand circular polarisations (CPs) are generated in the four‐arm spiral antenna, whose circumference is less than three wavelengths, by properly exciting the spiral arms from their inner ends. Similar analogy can be used to extend the concept to any multi‐arm spiral antenna. The proposed compact antenna, which is backed by a planar reflector surface, is designed and extensively investigated to study main antenna specifications including gain, cross polarisation, and pattern symmetry, for dual‐polarised wireless communication systems. A 3 dB axial ratio frequency bandwidth of about 1.8–5.3 GHz is realised for both clockwise and counter‐clockwise CP with axial beams. Furthermore, superior pattern symmetry with equal beamwidths is attained for both senses of polarisation. A prototype antenna is fabricated and tested. Excellent agreement between the measured and computed results is observed. An asymptotic equation is also developed to estimate the antenna peak gain over the frequency band for both senses of CPs.
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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 | 0.000 |
| 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".