A Novel Impedance Matched Mode Generator for Excitation of the TE$_{21}$ Mode in Compact Dual-Mode Circular Waveguide Feeds
Bibliographic record
Abstract
A compact dual-mode circular waveguide horn antenna is presented that is fed by the dominant TE$_{11}$mode and generates the higher-order TE$_{21}$mode in order to reduce the cross polarization of offset reflectors. To excite the second mode, two blocks and a small discontinuity step are used. These blocks are tangent to the aperture of the second waveguide, as opposed to the traditional case where they are usually located right at the discontinuity step, which results in high reflections. An analytic model is then deployed to extract the mode content factor along with the field tapers of each mode in the principal planes. Other than far-field radiation patterns, emphasis is placed on the scattering parameters of the antenna, and they are compared to the ones for the same antenna with no blocks as well as the traditional case when the blocks are placed right at the discontinuity of the stepped waveguide. It is shown that the proposed feed provides a good impedance match, over a wide frequency band, similar to its counterpart for the single-mode antenna with no blocks. To verify the concept, a prototype antenna is fabricated and tested. There is an excellent agreement between the simulated and measured results.
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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 | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".