Broadband Compact Circularly Polarized Spiral Antenna Array Fed by Printed Gap Waveguide for Millimeter-Wave Applications
Bibliographic record
Abstract
This paper presents a new design for a wideband circularly polarized (CP) spiral antenna array fed by a differential aperture coupling. The differential excitation is realized by two vias located at the lateral sides of a transverse slot etched on the lower substrate. The proposed two-arm spiral antenna has a smaller size compared to conventional spiral antennas with several turns. The presented single radiating element provides the impedance bandwidth of (|S11| <; -10 dB) 40.4% and 3-dB axial ratio (AR) of 23.2% with a peak RHCP gain of 7.2 dBic over the operating frequency band. To further enhance the AR bandwidth and the maximum gain, the presented CP spiral element is employed in a 2×2 sequential feeding arrangement. The sequential feeding network is implemented using the low-loss printed gap waveguide (PGW) line, which is compatible with low-cost printed circuit board (PCB) technology. A prototype of the proposed 2×2 antenna array is fabricated and measured experimentally. Measured results reveal that the designed antenna array has a wide impedance bandwidth of over 48.5%, the 3-dB AR bandwidth of 34.2%, and the 3-dB gain bandwidth of 32.4% with a maximum gain of 11.74 dBic and excellent radiation efficiency of 85% over the entire operating frequency band.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".