Design of GaN-based Microwave Components and Application to Novel High Power Reconfigurable Antennas
Bibliographic record
Abstract
This thesis demonstrates the feasibility of using gallium nitride (GaN) technology in reconfigurable RF systems.GaN-based varactor diodes and switch circuits are pursued as promising candidates for high-power/high-frequency applications.The first part is devoted to active GaN device development.Active components were realized using the Canadian National Research Council (NRC) GaN HEMTs process.Based on three process, such as, GaN150v0 (gate length of 0.15um), GaN500v1 and GaN500v2 (both with gate length of 0.5um), many varactor diodes with size different have been manufactured and characterized via DC and RF smallsignal and large-signal measurements.Then, the varactor diodes were modeled by analytic equations containing empirical coefficients.These expressions have been introduced for the first time for the voltage dependency of equivalent capacitance (CEq) and series resistance (REq) and can be used as a general model to represent the nonlinear behavior of GaN based varactors.For small-signal operation, all of the developed equations describing REq and CEq are only bias voltage and device geometry dependent, while for large-signal operation, the influence of RF-power must be taken into account.In addition, different size single stand-alone switches were fabricated using GaN500v2.By analyzing the small-signal measurements, it was observed that the isolation is high at low frequencies but quickly drops with increasing frequency.Also, it was observed that the larger the device the lower the insertion loss and the poorer the isolation will be.Moreover, based on these small-signal measurements, a model was introduced.The second part addresses the integration and design aspects of the reconfigurable proposed circuits, such as tunable phase shifter, reconfigurable 3-dB 90° hybrid coupler, tunable frequency oscillator, beam switching antenna array and matching reconfigurable patch antenna operating below 10 GHz.Here the developed GaN varactors and switches are used for achieving the tenability purpose.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".