A study of the radiation efficiency of a half wavelength dipole
Bibliographic record
Abstract
Antenna efficiency directly impacts the efficiency of communications and sensing applications, and the emerging use of high frequencies has renewed interest in its mechanisms and estimation. In this paper, the radiation efficiency of the half-wavelength center-fed circular dipole is calculated for representative metals. Both the approximate and the accurate current distribution models for the wire cross section are used. The current distribution model for along the wire is the usual sinusoidal form. From the modeled current distribution, we calculate the ohmic resistance and the radiation efficiency of the dipole. The results quantify the wire thickness and frequency ranges for which the approximate model for the cross section current distribution holds, and demonstrates the limiting antenna loss at high frequencies. For SHF and EHF, using conductors such as stainless steel means that the ohmic resistance is in the same order as the radiation resistance. When using gold coatings at these frequencies, the situation improves, but a coating much larger than that available from regular sputtering is required to attain the limiting efficiency.
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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 | 0.000 | 0.000 |
| 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".