Modeling and Optimal Design of Multiple Air Holes in Microwave Substrate Integrated Waveguides
Modeling and Optimal Design of Multiple Air Holes in Microwave Substrate Integrated Waveguides
- 주제(키워드) Substrate integrated waveguide , Multiple air hole , Wave equation , Genetic algorithm , Electromagnetic bandgap
- 발행기관 아주대학교
- 지도교수 이해영
- 발행년도 2018
- 학위수여년월 2018. 8
- 학위명 박사
- 학과 및 전공 일반대학원 전자공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000027896
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
A wide range of potential applications using substrate integrated waveguide (SIW) technologies in conjunction with air hole regions is introduced, in which the representative modeling and analysis for the air hole SIW (AHSIW) are investigated. From previous studies I can conclude that it is important to analyze the air-filled region in SIW, efficiently and correctly, as the AHSIW is a promising transmission line platform for a low loss system configuration. Efficient optimization linked to the analysis is also required to extract the best physical parameters for the desired electrical parameters. In this dissertation, a novel efficient optimization methodology to cope with the multiple air-hole effect in SIW applications is proposed. The methodology adopts a genetic algorithm (GA) to obtain the optimum air hole dimensions for the specific propagation constant, accurately calculated by a novel recursive and closed-form equation. The novel recursive equation is derived from a general transverse electric (TE) mode wave equation (with boundary and phase matching condition) which is providing an accurate solution from a simple calculation. As for the closed-form equation, I use the energy equivalence concept with the assumption that the E-field amplitude is equal to the conventional SIW containing uniform dielectric material at the cut-off frequency region. The assumptions made in the closed-form equation are useful not only for estimating the frequency independent effective dielectric constant easily but also for calculating the recursive equation by Newton-Raphson method efficiently. In summary, the proposed novel optimization methodology is to combine the two proposed equations with the generic algorithm (GA). I propose novel representative applications for this approach such as a band pass filter, a lowpass filter, a diplexer, a impedance transformer, a phase shifter, and an electromagnetic bandgap (EBG) structure that are all based upon the AHSIW platform (and verified by either commercial full wave simulation and/or measurement). From the results, I will confirm that the proposed methodology is accurate and efficient. The accuracy is showing that the recursive formula is viable for correct analysis with negligible error caused by structural approximation. From the comparison with a full wave simulation, HFSS, I can see the results are in excellent agreement within 2% error even for the closed-form equation. It can be also useful to estimate the frequency independent effective dielectric constant correctly for the AHSIW although the equation does not fully comply with the Maxwell’s equation due to the cut-off wave number approximation. The accuracy helps to reduce the calculation time for solving the recursive equation by the Newton-Raphson’s method, which in turn helps to achieve a minimized total optimization process time that of around a minute to design the applications. Therefore, the proposed approach can provide an efficient optimization methodology to design low loss broad band SIW circuits for obtaining the optimum performance in microwave and mm-wave frequency range applications.
more목차
Ⅰ. Introduction
Ⅱ. Conventional Rectangular Waveguide (RWG)
A. Fundamentals of Rectangular Waveguide
1. TE Waves
B. Partially Loaded Waveguide
Ⅲ. Substrate Integrated Waveguide (SIW)
A. Fundamentals of SIW
1. Equivalent Rectangular Waveguide Model
2. Loss Consideration
3. Numerical Analysis
B. Representative Applications of SIW in Previous Studies
1. Filters
2. Phase Shifters
3. Coupler and Dividers
4. Antennas and Systems
Ⅳ. SIW with Multiple Air Holes
A. Previous Studies
1. Air Filled SIW (AFSIW)
2. SIW Bandpass Filter with Multiple Air Holes
3. Air Filled Resonant Cavity
B. Proposed Analysis Methods
1. Closed Form Equation
2. Recursive Formula from the Wave Equation
3. Discussion of the Calculation Error
Ⅴ. Optimization Using Genetic Algorithm (GA)
A. GA Introduction
B. Optimization Process
1. Restricted Tournament Selection
2. Chromosome and Population
3. Fitness Function
4. Genetic Operators
5. Variable Number of Holes
C. Optimization Results
Ⅵ. Applications and Validation
A. Bandpass Filter
B. Diplexer
C. Impedance Transformer
D. Lowpass Filter
E. Phase Shifter
F. Integration with EBG Structure
Ⅶ. Conclusion
References
Vita
