Tunnel conduction consequences in high frequency microcontacts; passive intermodulation effect
Bibliographic record
Abstract
The tunneling conduction effect across the electrical contacts of coaxial microwave electromechanical switches can be a major source of non-linearity in the current-voltage characteristics. This is similar to the case of coaxial cables, where the nonlinearity is attributed to the contact resistance at the RF connectors' interface. The current non-linearity occurs as an effect of the tunnel conduction, usually type II as classified by R. Holm, and it can be described both analytically and experimentally. The paper uses a quasi-experimental method to assess the non-linearity in the current-voltage characteristic of the switch microcontacts and, based on this, predicts the expected passive intermodulation levels for the switch. The interference phenomenon called passive intermodulation (PIM), in high power, multichannel systems, presents an important challenge in communication satellites as well as in the wireless industry. The non-linearities generate harmonics of the fundamental frequency, which 'mix' together to generate a predictable set of new frequencies that may interfere with the receive portion of the communication system. Historically, a number of models have been developed for coaxial cables, which assume the intermodulation sources are located in the RF connectors. The paper proposes a model for the intermodulation characteristics of the switch path that is based on a previously developed contact resistance model. A 5th order source point model is used because of the potential for a significant power content in the 3rd through 5th order equations, should these frequencies fall within the receive band. The results are compared with measured data for some typical RF coaxial electro-mechanical switches used in space applications; the measurement techniques are also discussed.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".