Broadband Circularly Polarized Helical Antenna Decoupling for Massive MIMO Applications
Bibliographic record
Abstract
In this letter, a circularly polarized (CP) massive multiple-input multiple-output (MIMO) antenna with wide impedance/axial ratio (AR) bandwidths and reduced size is proposed. The antenna element is based on a monofilar helical antenna (MHA) where an impedance transformer is adopted to improve the impedance and AR bandwidths, simultaneously. The mutual coupling of closely-packed MHAs is studied and a decoupling method is proposed by using a self-rotation method. A four-element helical MIMO antenna with enhanced impedance/AR bandwidths and radiation characteristics is firstly designed by employing the self-rotation and the sequential rotation techniques. Based on it, an 8 × 8 CP massive helical MIMO antenna is studied. The four-element and the 64-element helical MIMO antennas are prototyped and verified. The measured results demonstrate an overlapped bandwidth from 5.2 to 7.1 GHz providing a fractional bandwidth (FBW) of 30% for the four-element helical MIMO antenna, and a bandwidth from 5.7 to 6.6 GHz (FBW = 15%) for the 64-element massive helical MIMO antenna, respectively.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".