An approach to integrated frequency-comb filtering is presented, building from a background in photonic crystal cavity design and fabrication. Previous work in the development of quantum information processing devices through integrated photonic crystals consists of photonic band gap engineering and methods of on-chip photon transfer. This work leads directly to research into coupled-resonator optical waveguides which stands as a basis for the primary line of investigation. These coupled cavity systems offer the designer slow light propagation which increases photon lifetime, reduces size limitations toward on-chip integration, and offers enhanced light-matter interaction. A unique resonant structure explained by various numerical models enables comb-like resonant clusters in systems that otherwise have no such regular resonant landscape (e.g. photonic crystal cavities). Through design, simulation, fabrication and test, the work presented here is a thorough validation for the future potential of coupled-resonator filters in frequency comb laser sources.

Yes / The antenna array designed to operate over 0.450-0.475 Terahertz comprises two dielectric resonators (DRs) that are stacked vertically on top of each other and placed on the surface of the slot antenna fabricated on a silicon substrate using standard CMOS technology. The slot created in the silicon substrate is meandering and is surrounded by metallic via-wall to prevent energy dissipation. The antenna has a maximum gain of 4.5dBi and radiation efficiency of 45.7% at 0.4625 THz. The combination of slot and vias transform the antenna to a metamaterial structure that provides a relatively small antenna footprint. The proposed series-fed double DRs on-chip antenna array is useful for applications in THz integrated circuits. / Partially supported by innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424 and the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E0/22936/1.

The aim of this work is the study of methods of determination of electrophysical parameters of materials non-resonant and resonant methods. In the course of the work performed were considered the existing methods of determination of electrophysical parameters of materials in the field of high, ultra high and extremely high frequencies offered by the leading manufacturers on the market of measuring equipment. As a result of this work, we analyzed the methods for finding the values of electrical parameters of investigated materials for different frequency ranges. The results of the work were carried out practical measurements and conclusions about the applicability of the considered methods. / Целью данной работы является исследование методов определения электрофизических параметров материалов нерезонансными и резонансными методами. В ходе выполненной работы были рассмотрены существующие методы определения электрофизических параметров материалов в области высоких, сверхвысоких и крайне высоких частот, которые предлагаются ведущими производителями на рынке измерительного оборудования. В результате выполненной работы были проанализированы методы нахождения значений электрофизических параметров исследуемых материалов для различных диапазонов частот. По результатам работы были проведены практические измерения и сделаны выводы о применимости рассматриваемых методов.

PM2.5 particle sensing has been done using surface acoustic wave based sensor for two different frequencies. Due to mass loading and elasticity loading on the sensor's surface, the center frequency of the sensor shifts. The particle concentration can be tracked based on that frequency shift. The fit factor test has been conducted using higher frequency SAW sensor. The consist results has been achieved for particle sensing and fit factor test with SAW based sensor.

With the rapid advancement of autonomous vehicles, reliable and efficient wireless communication systems with high data rates have become essential for their safe and efficient operation and further evolution. High data rates are found in the higher frequency bands where conductive antennas lack radiation efficiency. To achieve high radiation efficiency, researchers tend towards using Circular Polarized Dielectric Resonator Antennas (CP-DRA). However, there is a lack of studies that cover the FR2 5G bands n257, n258, n261 suggested by 3GPP which is needed if vehicles were to drive across regional borders. This project addresses the challenges of achieving suitable CP-DRA performance for autonomous vehicle communication aimed at covering these FR2 5G bands. The objective is to design and simulate an optimized CP-DRA antenna that meets the required performance characteristics for further use in a phased array for efficient communication in the high-frequency FR2 5G bands. The objective was fulfilled by producing a model of a CP-DRA antenna that covers the mentioned FR2 5G bands. The antenna array achieves this with an axial ratio beam width at plus/minus 20 degrees azimuth angle and peak gain of 9-12 dBi throughout the frequency range. The model consists of four cylindrical resonator antenna elements excited in phase quadrature by a slot aperture feeding network to accomplish the circular polarization. The radiation efficiency of the model is 94% throughout the frequency range with an impedance bandwidth of < -15 dB. A prototype was built and tested that vaguely verified the beam pattern and center frequency. Future work includes building a prototype more comparable to the model for further verification of the circularly polarized gain pattern.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24584号 / 工博第5090号 / 新制||工||1975(附属図書館) / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 篠原 真毅, 教授 大村 善治, 教授 小嶋 浩嗣, 教授 引原 隆士 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

A bass-reflex system is a type of loudspeaker design that uses a port or a vent to improve low-frequency performance. The port acts as a Helmholtz resonator which extends the bass response of the system. However, at high drive levels, the air inside the port can become turbulent and cause distortion, noise, and compression. From previous works, it is known that the geometry of the port plays a crucial role in reducing these unwanted effects. This paper serves to provide more insight into optimal port shape by performing several objective tests on a group of 5 different prototype port shapes based on findings from previous literature. Total Harmonic Distortion (THD) and port compression tests were conducted to determine which port presented the highest performance.

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