Dispersion Engineered Radiative & Guided-Wave Electromagnetic Structures for Efficient Wave Control
Bibliographic record
Abstract
Dispersion engineering is the process of controlling the phase response of an electromagnetic (EM) structure as a function of frequency, which in turn determines the propagation characteristics of EM waves in the structure.This thesis presents two novel dispersion engineered structures for controlling the propagation properties of EM waves for two different applications.The first structure is a low-profile dielectric choke ring for multipath mitigation for global navigation satellite systems (GNSS) applications.The proposed structure has a dual-band surface impedance resonance and it is designed by engineering the surface impedance to strategically introduce two resonant frequencies around the GNSS bands of L2 (1227.60MHz) and L1 (1575.42MHz).This provides capacitive surface impedances around both bands simultaneously, required for efficient surface wave suppression for higher multipath rejection performance.To demonstrate the proposed principle of surface impedance engineering, an in-house choke ring prototype of the proposed design is tested with the widely used Dorne & Margolin (DM) antenna on top of it.A high multipath rejection in both GNSS bands is experimentally confirmed with comparable performances to an otherwise bulky, heavy, and expensive conventional metallic choke ring.The proposed design further provides 58% reduction in height and 26% reduction in diameter using a low-cost FR4 dielectric material.The second structure is an amplitude-equalized group delay device, called a phaser, for analog signal processing (ASP) applications, implemented at microwave and millimeter-wave (mm-wave) frequencies.The proposed devices achieve a flat magnitude transmission while preserving their strong dispersive group delay response.The microwave phaser is realized using C-sections, and the mm-wave phaser is realized using micro-ring resonators implemented using half-mode substrate integrated waveguide (HMSIW) structures.Both types of phasers are successfully demonstrated using full-wave simulations, with experimental demonstration currently underway for the active configurations.My deepest gratitude and appreciation go to my supervisors Prof. Shulabh Gupta and Prof. Jim Wight.I would like to thank Prof. Wight for bringing in his unparalleled knowledge and experience whenever I faced challenges along the way.I would also like to thank Prof. Gupta for his encouragement, mentorship, and for always being available to advise and guide me.Prof. Gupta's tremendous energy and passion for research have inspired me to learn and grow which made my experience truly enjoyable
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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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".