Thesis--Ph. D., University of Hong Kong, 1979.

The studies of the designs on true-time-delay lines (TTDLs), n-bit digital phase shifters and wideband switched-line phase shifters using composite right/left-handed transmission-line (CRLH TL) unit cells are presented in this thesis. To simplify these designs, a symmetrical CRLH TL unit cell having equal input and output impedance is proposed. In the design of TDDLs, the symmetrical CRLH TL unit cell with higher time-delay efficiency helps achieve a size reduction of 67.9%, compared with the TTDL designed using right-handed transmission line (RH TL). The symmetrical CRLH TL unit cell is further modified to a compact CRLH TL unit cell to further reduce the size by 58%. For performances comparison, the TTDLs using the compact CRLH TL unit cells, symmetrical CRLH TL unit cells and RH TL are studied using computer simulation and measurement. Results show that the TTDLs using the compact CRLH TL unit cells can achieve much longer time delays. The TTDLs designed using CRLH TL unit cells have narrow bandwidths because CRLH TL unit cells have narrow bandwidths. In this thesis, a wideband unit cell obtained by rotating the CRLH TL unit cell by 900is proposed in the design of TTDLs. Simulation and measurement show that the TTDL using wideband unit cells can achieve a time delay about 3 times and 6 times longer than that of the periodic microstrip line (PML) and RH TL, respectively. A 2-bit, 3-bit and 6-bit phase shifters using symmetrical CRLH TL unit cells are designed using computer simulation. In these designs, positive-intrinsic-negative (PIN) diodes mounted on the fingers of the CRLH TL unit cells are used as switches to control the phase response at the output. Different phase shifts are achieved using different switching states determined by controlling bits. The phase shifters are fabricated and measured. Simulated and measured results agree very well. Power-handling capability is also analyzed using surface-current density on the CRLH TL unit cells. Results show that the phase shifters have much higher power-handling capabilities than that of the PIN diodes. A wideband 1800-switched-line phase shifter using symmetrical CRLH TL unit cell is proposed. The switched-line phase shifter employs a symmetrical CRLH TL unit cell as the reference arm and a RH TL as the delay arm to produce a constant phase shift across a wide frequency band. For comparison, a traditional 1800-switched-line phase shifter using RH TLs for both reference and delay arms is also designed. To reduce the size, the CRLH TL unit cell is realized using lump elements (LEs). Wideband 900-and 1800-switched-line phase shifters using LE-CRLH TL unit cells are studied and compared with the traditional 900-and 1800-switched-line phase shifters. Simulated and measured results show that the proposed designs using symmetrical CRLH TL unit cells and LE-CRLH TL unit cells have very constant phase shifts with smaller variations compared with the traditional designs. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Accurate, efficient and general computational techniques are developed to evaluate the scattering parameters of passive microstrip components composed of discontinuities in microstrip transmission lines on general two layer substrates with single and two level metallization. An open domain model is used. The Electric Field Integral Equation is examined and the Green's function for single and double layer dielectric substrates on a infinite ground plane are reviewed while emphasizing the important computational details to the model, including singularity of the kernel, evaluation of the Sommerfeld Integrals, and interpolation of the Green's functions. In order to model accurately complex circuit geometries, two dimensional currents are used. Different basis functions for expansion and for testing are chosen in order to make the computation more efficient and allow for structures having general shape in the moment method formulation. A transmission line current source is used to model the parameters are flowing in and circuit evaluated out of structure. Structures excitation and the scattering by calculating the currents each of the N-ports of the such as microstrip bends, microstrip crossovers of arbitrary angle, and coupled microstrip discontinuities are analyzed. To validate the model, results of some elementary structures are compared with published results of other models. / Graduation date: 1992

Thesis, Ph.D., University of Hong Kong, 1979. / Also available in print.

Thesis (M.E.)--University of Canterbury, 2008. / Typescript (photocopy). "June 2008." Includes bibliographical references (p. [89]-92). Also available via the World Wide Web.

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, March 1990. / Thesis Advisor(s): Atwater, H.A. Second Reader: Lee, H. M. "March 1990." Description based on signature page as viewed on August 26, 2009. DTIC Descriptor(s): Strip Transmission Lines, Computer Aided Design, Computerized Simulation, Parameters, Microwave Equipment, Radar, Full Wave Rectifiers, Transmittance, Resonant Frequency, Construction, Wave Propagation, Coefficients, Boundary Value Problems, Resonators, Circuits, Discontinuities, Ka Band, Models, Scattering, Equivalent Circuits, Frequency. Author(s) subject terms: Millimeter wave, suspended substrate, design model. Includes bibliographical references (p. 78-79). Also available online.

Not available / text

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

by Terry Kin-chung Lo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaf 128). / Dedication --- p.i / Acknowledgements --- p.ii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Outline of Thesis --- p.1 / Chapter 1.2 --- Microstrip to Slotline Transition --- p.3 / Chapter 1.3 --- Finite Difference as a Numerical Method --- p.4 / Chapter Chapter 2 --- The Method of Finite Difference in Time Domain / Chapter 2.1 --- An Introduction and Brief History --- p.1 / Chapter 2.2 --- The Methodology of FDTD --- p.11 / Chapter 2.3 --- The Yee's Algorithm --- p.13 / Chapter 2.4 --- Stability Criterion --- p.19 / Chapter 2.5 --- Interfaces Between Media --- p.21 / Chapter 2.6 --- Lattice Truncation Condition --- p.24 / Chapter 2.7 --- Error Analysis --- p.28 / Chapter 2.8 --- Implementation of Programs --- p.33 / Chapter 2.9 --- Summary --- p.35 / Chapter Chapter 3 --- Absorbing Boundary Conditions / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Mur's ABC --- p.40 / Chapter 3.3 --- Liao's ABC --- p.42 / Chapter 3.4 --- Dispersive ABC --- p.45 / Chapter 3.5 --- Comparison between Mur's ABC & Liao's ABC --- p.47 / Chapter 3.6 --- "Comparison among Mur's 1st Order ABC, Liao's ABC & DBC" --- p.51 / Chapter 3.7 --- Summary --- p.55 / Chapter Chapter 4 --- Microstrip-Slotline Transitions / Chapter 4.1 --- Introduction --- p.57 / Chapter 4.2 --- Approach --- p.59 / Chapter 4.3 --- Single Quarter-Wave Microstrip-Slotline Transitions --- p.67 / Chapter 4.4 --- Single Y-Strip-Slotline Transitions --- p.78 / Chapter 4.5 --- Shorted-Stub Y-Strip-Slotline Transitions --- p.88 / Chapter 4.6 --- Y-Strip-180°-Slotline Transitions --- p.96 / Chapter 4.7 --- Y-Strip-Y-Slot Transitions --- p.104 / Chapter 4.8 --- Y-Strip-Open-Stub-Y-Slot Transitions --- p.112 / Chapter 4.9 --- YY-Transitions --- p.120 / Chapter 4.10 --- Summary --- p.127 / Chapter Chapter 5 --- Conclusions & Future Development / Chapter 5.1 --- Conclusions --- p.129 / Chapter 5.2 --- Future Development --- p.131 / Appendix / Fortran 77 Code of Single Quarter-Wave Microstrip-Slotline Transition --- p.132

In the analysis of optically controlled microstrip interdigitated gaps, an equivalent circuit model for simple interdigitated gap is obtained. As far as we know, this is the first report of optically controlled microstrip interdigitated gap equivalent circuit model. The amplitude and phase changes of interdigitated gaps under different illumination powers are calculated with this equivalent circuit model, which basically agree with the experimental results. Meanwhile, the effect on the transmission characteristics from the gap dimensions is also discussed. Finally a novel gap structure is described for optically controlled phase shifter application, whose transmission characteristics have nearly zero amplitude change and no less than 27 degrees phase change under different illumination powers when the transmission signal frequency is about 1.8 to 2.5GHz. Some detailed experimental results of this gap are presented in Chapter 5. / In this dissertation, a systematic work has been done to analyze the transmission characteristics and applications of optically controlled microstrip single gap and interdigitated gap devices on high resistivity silicon (HRS) wafer. Detailed simulations, experiments and the relative equivalent circuit models for these gap structures are presented. / Microwave photonics is a multi-disciplinary area that studies the interactions between microwave signals and optical signals. As one of the key elements, direct optical control of microwave semiconductor devices has been an area of growing interest since 1980's. They can be widely used in picosecond photoconductive switch, phase shifter, attenuator, high-speed sampling, gain control of amplifier and so on. / Some future work is also suggested based on the study in this dissertation. / Specifically, optically controlled microstrip discontinuities devices fabricated on semiconductor substrates have wide-ranging applications due to their simple fabrication, easy integration with other passive and active microwave devices. / When illuminated on the surface of the microstrip single gaps, the S 12 amplitude of this gap increases linearly as the optical illumination increasing, which is a good potential application for digital controllable attenuator. The change of the S12 amplitude is mainly due to the imaginary permittivity change of the HRS substrates. The equivalent circuit model is established to explain the amplitude and phase changed. The equivalent resistors have been calculated according to the excess carrier concentration profile after illumination, which match well with the experimental results. / Li Huiping. / "March 2005." / Adviser: K. T. Chan. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6619. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.