Low-cost free-space measurement of dielectric constant at Ka band
Bibliographic record
Abstract
A detailed method for determining the dielectric constant of materials using a Ka-band free-space transmission/reflection measurement system is presented. Since the measurement system was designed to minimise the overall cost of the system, correction terms and a smoothing process were necessary to account for limitations in the hardware. The different steps involved in the determination process are explained and their effect on the S-parameters is presented. A through-reflect-match (TRM) free-space calibration method was used, which greatly reduces system errors owing to its simple and stationary nature. The dynamic range of the measurement system after TRM calibration appeared to be better than 50 dB for the reflection coefficient and 29 dB for the transmission coefficient. To determine the unknown dielectric constant of the material, two numerical extraction techniques, a root-finding algorithm and a genetic algorithm were used. Dielectric constant results for a commercially available microwave substrate material sample are presented for both extraction techniques. The difference between the two extraction techniques was <1%. Comparison of the dielectric constant value with measurement performed by a standards testing organisation revealed an agreement within 2%.
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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 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".