Demand for wireless network capacity keeps growing exponentially every year, as a result a 1000-fold increase in data traffic is projected over the next 10 years in the context of 5G wireless networks. Solutions for delivering the 1000-fold increase in capacity fall into three main categories: deploying smaller cells, allocating more spectrum and improving spectral efficiency of wireless systems. Smaller cells at RF frequencies (1-6GHz) are unlikely to deliver the demanded capacity increase. On the other hand, millimeter-wave spectrum (frequencies over 24GHz) offers wider, multi-GHz channel bandwidths, and therefore has gained significant research interest as one of the most promising solutions to address the data traffic demands of 5G. Another disruptive technology is full-duplex which breaks a century-old assumption in wireless communication, by simultaneous transmission and reception on the same frequency channel. In doing so, full-duplex offers many benefits for wireless networks, including an immediate spectral efficiency improvement in the physical layer. Although FD promises great benefits, self-interference from the transmitter to its own receiver poses a fundamental challenge. The self-interference can be more than a billion times stronger than the desired signal and must be suppressed below the receiver noise floor. In recent years, there has been some research efforts on fully-integrated full-duplex RF transceivers, but mm-wave fully-integrated full-duplex systems, are still in their infancy. This dissertation presents novel architectures, antenna and circuit techniques to merge two exciting technologies, mm-wave and full-duplex, which can potentially offer the dual benefits of wide bandwidths and improved spectral efficiency. To this end, two different antenna interfaces, namely a wideband reconfigurable T/R antenna pair with polarization-based antenna cancellation and an mm-wave fully-integrated magnetic-free non-reciprocal circulator, are presented. The polarization-based antenna cancellation is employed in conjunction with the RF and digital cancellation to design a 60GHz full-duplex 45nm SOI CMOS transceiver with nearly 80dB self-interference suppression. The concepts and prototypes presented in this dissertation have also profound implications for emerging applications such as vehicular radars, 5G small-cell base-stations and virtual reality.

Chen, Kejian. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 156-164). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

Este trabalho, realizado junto ao Grupo de Novos Materiais e Dispositivos (GNMD) pertencente ao Laboratório de Microeletrônica (LME) da Universidade de São Paulo, teve como objetivo correlacionar algumas propriedades físico-químicas de filmes finos de Ba1-XSrxTiO3 (BST), obtidos pela técnica de pulverização catódica reativa (sputtering), com os parâmetros de deposição, visando a fabricação de defasadores inteligentes operando em 60 GHz. Propriedades como cristalinidade e composição química foram estudadas e relacionadas com o tipo de substrato sobre o qual os filmes finos de BST foram depositados, e com os diversos parâmetros de deposição variados. Foi observada uma forte influência dos parâmetros de deposição, principalmente da temperatura e do tipo de substrato, na cristalinidade dos filmes. Os filmes depositados sobre cobre são mais cristalinos do que aqueles depositados sobre Si. Já a composição química dos filmes não variou significativamente, mantendo-se próxima à do alvo de sputtering utilizado, independentemente do substrato ou das condições de deposição. As propriedades elétricas dos filmes fabricados foram extraídas de capacitores de placas paralelas construídos utilizando o BST como dielétrico linear. As curvas de capacitância vs tensão a 1 MHz destes capacitores permitiram determinar uma variação de tunabilidade de até 44 %, para uma permissividade elétrica relativa de 310, valores estes compatíveis com aqueles encontrados na literatura. As propriedades elétricas dos filmes produzidos permitiram projetar um defasador de 1,3 mm2, com uma figura de mérito de 30º/dB para uma defasagem de 360º. / This work, performed at the New Materials and Devices Group (GNMD) of the Microelectronics Laboratory of the Polytechnic School of the University of São Paulo, has the objective to correlate reactive sputtered-BST thin films to its deposition parameters, aiming to produce a 60 GHz tunable phase shifter. Thin film crystallinity and stoichiometry were correlated with sputtering deposition parameters and the type of substrate. A strong influence of the sputtering parameters was observed on BST crystallinity, mainly the temperature and the type of substrate. Thin films on copper are more crystalline than on Si (100). The stoichiometry, on the other hand, did not change as function of the deposition parameters or the substrate in both cases. The thin films electrical properties were obtained by capacitance vs voltage measurements, with the BST as linear dielectric of a parallel plate capacitor. The capacitors 1 MHz C-V characterization showed tunabilities as high as 44%, for an electrical permittivity of 310. These properties allowed a phase shifter project, resulting a 1,3 mm2 device with a figure of merit of 30 º/dB for 360 º phase shift.

Millimeter wave imaging systems are the next generation imaging systems being developed for security and surveillance purposes. In this work, thin film metal-insulator-metal (MIM) tunnel junction based detector using Ni-NiO-Cr has been developed for the first time for millimeter wave detection operating at 94 GHz. Extensive process development has been carried out to fabricate the MIM junctions. Arrays of MIM junctions with 1 µm² contact area and ultra-thin insulator layer of ~3 nanometer have been developed using e-beam lithography and reactive sputtering, respectively. MIM diodes were also fabricated in a bulk-micromachined diaphragm configuration to minimize surface wave loss. DC and millimeter wave measurements were carried out on the fabricated diodes to determine the device characteristics and performance. The current-voltage (I-V) measurements yielded current in the range of few µA with significant non-linearity and asymmetry. A maximum sensitivity of 7 V-1 was also obtained from the fabricated diode. These tunnel junctions showed a positive response to millimeter wave signal, with output current in the range of few µA. By controlling the input power of the millimeter wave signal, the output current from the device could be varied. Additionally, MIM diodes with 100 µm² contact area were developed using optical lithography technique. The I-V characteristics of diode demonstrated a uniform behavior, with a sensitivity value of 15 V-1. Furthermore, the diodes were utilized to observe the effects of post-deposition annealing on the diode I-V behavior. The I-V measurement provided evidence of diode operation up to 350°C, with optimal operation at 250°C. Finally, the feasibility of using an organic insulator was also investigated. MIM junctions were fabricated with a thin layer of polyaniline using Langmuir-Blodgett deposition process. The electrical characteristics of the polyaniline based MIM junction was determined by evaluating its I-V response. The use of an alternate dielectric proved successful, yielding a significant non-linearity and asymmetry. However, the output current obtained from these junctions was in the order of nano-Amperes. By optimizing the deposition process, the organic MIM junctions can be developed to yield better device characteristics.

Pulsed terahertz (THz) systems are an emergent technology, finding diverse applications as they approach maturity. From their birth in the late 1980's to the wealth of alternate sources and imaging modalities now available, the rise has been fuelled by the expectation that this will prove a world changing technology. This Thesis takes an application focused approach and seeks to provide enabling systems and algorithms for the development of functional imaging systems with broad potential application in security inspection, non-destructive testing and biomedical imaging. Three dimensional pulsed THz imaging systems were first introduced in 1996 using a reflection-mode ultrasound-like configuration. This Thesis builds upon this former work by focusing on transmission mode tomography systems using pulsed THz radiation. Several novel 3D imaging modalities are introduced. The hardware architectures, based on optoelectronic generation and detection of THz radiation are described. Approximations to the wave equation are derived, allowing linear reconstruction algorithms to recover 3D structural information fromthe transmitted THz field. Finally the systems are demonstrated and the achievable resolution and image quality are investigated. Three imaging architectures are developed herein: 1. T-ray holography allows the 3D distribution of point scatters to be resolved based on a single projection image utilising a novel reconstruction algorithm based on the windowed Fourier transform and back-propagation of the Fresnel-Kirchhoff diffraction equation. 2. T-ray diffraction tomography utilises the diffracted THz field to allow a Helmholtz equation based, frequency-dependent reconstruction to be performed and the THz spectrum at each pixel to be calculated. 3. T-ray Computed Tomography (CT) uses analogous techniques to X-ray CT, based on the Radon transform, to provide 3D T-ray reconstructions of unprecedented fidelity. These techniques have important applications in material identification, which is investigated in the second part of this Thesis. Pulsed THz spectroscopy has been widely acclaimed for its potential to identify different materials based on their spectral properties. The second part of this Thesis presents algorithms towards this goal. Three case studies are performed focusing on biomaterial classification, anthrax detection and in vitro osteosarcoma cell differentiation. A classification framework is developed to process the THz spectral data and identify specific materials. A linear filter model is introduced to describe the system response of different materials, and the filter taps are utilised for feature extraction. This technique is demonstrated for biomaterial and anthrax classification. For cell differentiation a genetic algorithm is used to select deconvolved frequency components to train a classifier. In each case a high classification accuracy is demonstrated, highlighting the promise and potential of three dimensional T-ray inspection systems. / Thesis (Ph.D.)--School of Electrical and Electronic Engineering, 2004.

"December, 2003" / Includes bibliographical references (p. 311-348) / Accompanying CD-ROM entitled: 'SPM_PhD_Thesis' contains MATLAB_Algorithms (algorithms for T-ray data analysis and display, as described in the Thesis); Appendix D (Example_Raw_Data_Files - examples of raw T-ray data files, used by the MATLAB algorithms in MATLAB_Algorithms); and Thesis_PDF (a copy of the Thesis printed in Adobe's Portable Document Format (PDF)). / System requirements for accompanying CD-ROM: CD-ROM drive ; Adobe Acrobat reader ; Matlab software. / xxxiv, 358 p. : ill. (col.) ; 30 cm. + 1 CD-ROM (col. ill. ; 4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Electrical and Electronic Engineering, 2004

<p>Automotive Radars have introduced various functions on automobiles for driver’s safety and comfort, as part of the Intelligent Transportation System (ITS) including Adaptive Cruise Control (ACC), collision warning or avoidance, blind spot surveillance and parking assistance. Although such radar systems with 24 GHz carrier frequency are already in use but due to some regulatory issues, recently a permanent band has been allocated at 77-81 GHz, allowing for long-term development of the radar service. In fact, switchover to the new band is mandatory by 2014.</p><p>A frequency multiplier will be one of the key components for such a millimeter wave automotive radar system because there are limitations in direct implementation of low phase noise oscillators at high frequencies. A practical way to build a cost-effective and stable source at higher frequency is to use an active multiplier preceded by a high spectral purity VCO operating at a lower frequency. Recent improvements in the performance of SiGe technology allow the silicon microelectronics to advance into areas previously restricted to compound semiconductor devices and make it a strong competitor for automotive radar applications at 79 GHz.</p><p>This thesis presents the design of active frequency doubler circuits at 20 GHz in a commercially available SiGe BiCMOS technology and at 40GHz in SiGe bipolar technology (Infineon-B7h200 design). Buffer/amplifier circuits are included at output stages to drive 50 Ω load. The frequency doubler at 20 GHz is based on an emitter-coupled pair operating in class-B configuration at 1.8 V supply voltage. Pre-layout simulations show its conversion gain of 10 dB at -5 dBm input, fundamental suppression of 25dB and NF of 12dB. Input and output impedance matching networks are designed to match 50 Ω at both sides.</p><p>The millimeter wave frequency doubler is designed for 5 V supply voltage and has the Gilbert cell-based differential architecture where both RF and LO ports are tied together to act as a frequency doubler. Both pre-layout and post-layout simulation results are presented and compared together. The extracted circuit has a conversion gain of 8 dB at -8 dB input, fundamental suppression of 20 dB, NF of 12 dB and it consumes 42 mA current from supply. The layout occupies an area of 0.12 mm2 without pads and baluns at both input and output ports. The frequency multiplier circuits have been designed using Cadence Design Tool.</p>

Ever growing demands for higher data rate and bandwidth are pushing extremely high data rate wireless applications to millimeter-wave band (30-300GHz), where sufficient bandwidth is available and high data rate wireless can be achieved without using complex modulation schemes. In addition to the communication applications, millimeter-wave band has enabled novel short range and long range radar sensors for automotive as well as high resolution imaging systems for medical and security. Small size, high gain antennas, unlicensed and worldwide availability of released bands for communication and a number of other applications are other advantages of the millimeter-wave band. The major obstacle for the wide deployment of commercial wireless and radar systems in this frequency range is the high cost and bulky nature of existing GaAs- and InP-based solutions. In recent years, with the rapid scaling and development of the silicon-based integrated circuit technologies such as CMOS and SiGe, low cost technologies have shown acceptable millimeter-wave performance, which can enable highly integrated millimeter-wave radio devices and reduce the cost significantly. Furthermore, at this range of frequencies, on-chip antenna becomes feasible and can be considered as an attractive solution that can further reduce the cost and complexity of the radio package. The propagation channel challenges for the realization of low cost and reliable silicon-based communication devices at millimeter-wave band are severe path loss as well as shadowing loss of human body. Silicon technology challenges are low-Q passive components, low breakdown voltage of active devices, and low efficiency of on-chip antennas. The main objective of this thesis is to investigate and to develop antenna and front-end for cost-effective silicon based millimeter-wave phased array radio architectures that can address above challenges for short range, high data rate wireless communication as well as radar applications. Although the proposed concepts and the results obtained in this research are general, as an important example, the application focus in this research is placed on the radio aspects of emerging 60 GHz communication system. For this particular but extremely important case, various aspects of the technology including standard, architecture, antenna options and indoor propagation channel at presence of a human body are studied. On-chip dielectric resonator antenna as a radiation efficiency improvement technique for an on-chip antenna on low resistivity silicon is presented, developed and proved by measurement. Radiation efficiency of about 50% was measured which is a significant improvement in the radiation efficiency of on-chip antennas. Also as a further step, integration of the proposed high efficiency antenna with an amplifier in transmit and receive configurations at 30 GHz is successfully demonstrated. For the implementation of a low cost millimeter-wave array antenna, miniaturized, and efficient antenna structures in a new integrated passive device technology using high resistivity silicon are designed and developed. Front-end circuit blocks such as variable gain LNA, continuous passive and active phase shifters are investigated, designed and developed for a 60GHz phased array radio in CMOS technology. Finally, two-element CMOS phased array front-ends based on passive and active phase shifting architectures are proposed, developed and compared.

Ever-increasing interest in millimeter-wave and terahertz spectrum has prompted research and development of novel passive components working at these frequencies. Compared with the conventional planar components, non-planar dielectric devices become more attractive as frequencies increase due to their higher quality factors and dimensional tolerances. In this thesis, we present fast methods to analyze the millimeter-wave dielectric resonator and rod antenna. First, an analytical method has been developed to evaluate resonant frequencies, quality factors of the Whispering Gallery Mode (WGM) disk resonators and also the resonator-waveguide coupling. A numerical solver based on full-wave finite element method is implemented to verify the analytical result. This analytical model provides a solution for fast design and optimization of WGM resonators in filter and sensor applications. Secondly, a fast analytical approach based on local mode theory is introduced to calculate the radiation from tapered dielectric rod antenna. This efficient approximate model consumes much less computing resources and time, and demonstrates good agreements with full-wave numerical results. It supplies a quantitative way to understand the radiation mechanism and interaction between different parts of the antenna. Based on this, design criteria for the taper profile of rod antennas are given.

Automotive Radars have introduced various functions on automobiles for driver’s safety and comfort, as part of the Intelligent Transportation System (ITS) including Adaptive Cruise Control (ACC), collision warning or avoidance, blind spot surveillance and parking assistance. Although such radar systems with 24 GHz carrier frequency are already in use but due to some regulatory issues, recently a permanent band has been allocated at 77-81 GHz, allowing for long-term development of the radar service. In fact, switchover to the new band is mandatory by 2014. A frequency multiplier will be one of the key components for such a millimeter wave automotive radar system because there are limitations in direct implementation of low phase noise oscillators at high frequencies. A practical way to build a cost-effective and stable source at higher frequency is to use an active multiplier preceded by a high spectral purity VCO operating at a lower frequency. Recent improvements in the performance of SiGe technology allow the silicon microelectronics to advance into areas previously restricted to compound semiconductor devices and make it a strong competitor for automotive radar applications at 79 GHz. This thesis presents the design of active frequency doubler circuits at 20 GHz in a commercially available SiGe BiCMOS technology and at 40GHz in SiGe bipolar technology (Infineon-B7h200 design). Buffer/amplifier circuits are included at output stages to drive 50 Ω load. The frequency doubler at 20 GHz is based on an emitter-coupled pair operating in class-B configuration at 1.8 V supply voltage. Pre-layout simulations show its conversion gain of 10 dB at -5 dBm input, fundamental suppression of 25dB and NF of 12dB. Input and output impedance matching networks are designed to match 50 Ω at both sides. The millimeter wave frequency doubler is designed for 5 V supply voltage and has the Gilbert cell-based differential architecture where both RF and LO ports are tied together to act as a frequency doubler. Both pre-layout and post-layout simulation results are presented and compared together. The extracted circuit has a conversion gain of 8 dB at -8 dB input, fundamental suppression of 20 dB, NF of 12 dB and it consumes 42 mA current from supply. The layout occupies an area of 0.12 mm2 without pads and baluns at both input and output ports. The frequency multiplier circuits have been designed using Cadence Design Tool.