Circuits and Systems for On-Chip RF Chemical Sensors and RF FDD Duplexers

Integrating RF bio-chemical sensors and RF duplexers helps to reduce cost and area in the current applications. Furthermore, new applications can exist based on the large scale integration of these crucial blocks. This dissertation addresses the integration of RF bio-chemical sensors and RF duplexers by proposing these initiatives. A low power integrated LC-oscillator-based broadband dielectric spectroscopy (BDS) system is presented. The real relative permittivity ε’r is measured as a shift in the oscillator frequency using an on-chip frequency-to-digital converter (FDC). The imaginary relative permittivity ε”r increases the losses of the oscillator tank which mandates a higher dc biasing current to preserve the same oscillation amplitude. An amplitude-locked loop (ALL) is used to fix the amplitude and linearize the relation between the oscillator bias current and ε”r. The proposed BDS system employs a sensing oscillator and a reference oscillator where correlated double sampling (CDS) is used to mitigate the impact of flicker noise, temperature variations and frequency drifts. A prototype is implemented in 0.18 µm CMOS process with total chip area of 6.24 mm^2 to operate in 1-6 GHz range using three dual bands LC oscillators. The achieved standard deviation in the air is 2.1 ppm for frequency reading and 110 ppm for current reading. A tunable integrated electrical balanced duplexer (EBD) is presented as a compact alternative to multiple bulky SAW and BAW duplexers in 3G/4G cellular transceivers. A balancing network creates a replica of the transmitter signal for cancellation at the input of a single-ended low noise amplifier (LNA) to isolate the receive path from the transmitter. The proposed passive EBD is based on a cross-connected transformer topology without the need of any extra balun at the antenna side. The duplexer achieves around 50 dB TX-RX isolation within 1.6-2.2 GHz range up to 22 dBm. The cascaded noise figure of the duplexer and LNA is 6.5 dB, and TX insertion loss (TXIL) of the duplexer is about 3.2 dB. The duplexer and LNA are implemented in 0.18 µm CMOS process and occupy an active area of 0.35 mm^2

Amplificadores de potência para radiofrequência insensíveis à impedância de carga

Solid state power amplifiers (SSPAs) evolved significantly over the last few decades, mainly, due to the use of new transistor technologies, such as gallium nitride (GaN) high-electron-mobility transistors (HEMTs), very advanced computer-aided design (CAD) software, and very effective digital pre-distortion (DPD) algorithms. This led to a considerable performance improvement, in terms of energy efficiency, output power, and linearity. To achieve this performance, power amplifier (PA) designers normally push the used transistors very close to their physical safe operating limits, and consider them to operate for a fixed output load. However, the designed PAs are used for many different industrial and/or telecommunication applications, and, in some cases, such as, for example, microwave cooking or massive multiple-input multiple-output (MIMO) fifth generation (5G) base stations (BSs), the output load of these amplifiers can change. Under this nonoptimal scenario, the used transistors will operate for non-nominal loads, and the PAs performance can be severely degraded. Moreover, in highly optimized designs, where the transistors are operated close to their safe limits, their reliability can be reduced or, in extreme cases, they can even be permanently damaged. Therefore, load insensitive PA architectures, and/or techniques that aim at reducing the load variation seen by the PA, are necessary to improve the performance under load varying scenarios. This thesis presents various strategies to improve load insensitiveness of PAs. The presented techniques are based on tunable matching networks (TMNs) and on the amplifiers’ drain supply voltage (VDS) variation. The developed TMNs successfully reduced the load variation seen by the PA, and its performance was greatly improved, for non-optimal loading, by also using the derived load dependent VDS variation. These different approaches were tested and validated on single-ended PAs and then, based on their advantages and disadvantages, the most promising technique – the supply voltage modulation – was selected for the design of a Doherty power amplifier (DPA), which is of paramount importance for telecommunication applications. Moreover, since in some applications the output load variation can be unpredictable, we also developed a complete quasi-load insensitive (QLI) PA system that includes an impedance tracking circuit and an automatic real-time compensation of the amplifier performance.Os amplificadores de potência de estado sólido (SSPAs) evoluíram significativamente nas últimas décadas, principalmente devido à utilização de novas tecnologias de transístores, como os transístores de alta mobilidade (HEMTs) de nitreto de gálio (GaN), de ferramentas muito avançadas de projeto assistido por computador (CAD) e de algoritmos de pré-distorção digital (DPD) muito evoluídos. Isto levou a uma melhoria de desempenho considerável, em termos de eficiência energética, potência de saída e linearidade. Normalmente, para obter estes níveis de desempenho, os engenheiros projetam os amplificadores permitindo que os transístores utilizados operem muito perto do seu limite físico de funcionamento seguro e considerando que vão operar para uma carga fixa. No entanto, os amplificadores projetados são utilizados em diversas aplicações industriais e/ou telecomunicações e, em alguns casos, como por exemplo fornos micro-ondas ou estações base 5G, a sua carga de saída pode variar devido a várias causas, que podem ser previsíveis ou imprevisíveis. Neste cenário não ideal, os transístores utilizados operam para cargas não ótimas e o desempenho dos amplificadores pode ser muito degradado. Além disso, em projetos muito otimizados, onde os transístores são operados perto do seu limite de funcionamento seguro, a sua durabilidade pode ser reduzida ou, em casos extremos, podem até ser permanentemente danificados. Portanto, para melhorar o desempenho dos amplificadores em cenários de carga variável, são necessárias novas arquiteturas e/ou técnicas que visam reduzir a variação da carga vista pelos transístores utilizados. Esta tese apresenta várias estratégias para melhorar a insensibilidade dos amplificadores em relação à variação de carga. As técnicas apresentadas são baseadas em malhas de adaptação dinâmicas (TMNs) e na variação da tensão de alimentação dos amplificadores. As malhas de adaptação desenvolvidas permitiram reduzir a variação de carga vista pelo amplificador e a variação da sua tensão de alimentação permitiu melhorar o desempenho para operação com cargas não ótimas. Estas abordagens foram testadas e validadas em amplificadores baseados num só transístor, e, posteriormente, com base nas suas vantagens e desvantagens, a técnica mais promissora – a modulação da tensão de alimentação – foi selecionada para o projeto de um amplificador Doherty, que é imprescindível para telecomunicações. Além disso, como em algumas aplicações a variação da carga de saída pode ser imprevisível, também desenvolvemos um sistema completo que inclui um circuito de medida de impedância e compensação do desempenho do amplificador em tempo real.Programa Doutoral em Engenharia Eletrotécnic

System-Level Integrated Circuit (SLIC) Technology Development for Phased Array Antenna Applications

This report documents the efforts and progress in developing a 'system-level' integrated circuit, or SLIC, for application in advanced phased array antenna systems. The SLIC combines radio-frequency (RF) microelectronics, digital and analog support circuitry, and photonic interfaces into a single micro-hybrid assembly. Together, these technologies provide not only the amplitude and phase control necessary for electronic beam steering in the phased array, but also add thermally-compensated automatic gain control, health and status feedback, bias regulation, and reduced interconnect complexity. All circuitry is integrated into a compact, multilayer structure configured for use as a two-by-four element phased array module, operating at 20 Gigahertz, using a Microwave High-Density Interconnect (MHDI) process. The resultant hardware is constructed without conventional wirebonds, maintains tight inter-element spacing, and leads toward low-cost mass production. The measured performances and development issues associated with both the two-by-four element module and the constituent elements are presented. Additionally, a section of the report describes alternative architectures and applications supported by the SLIC electronics. Test results show excellent yield and performance of RF circuitry and full automatic gain control for multiple, independent channels. Digital control function, while suffering from lower manufacturing yield, also proved successful

Applied Measurement Systems

Measurement is a multidisciplinary experimental science. Measurement systems synergistically blend science, engineering and statistical methods to provide fundamental data for research, design and development, control of processes and operations, and facilitate safe and economic performance of systems. In recent years, measuring techniques have expanded rapidly and gained maturity, through extensive research activities and hardware advancements. With individual chapters authored by eminent professionals in their respective topics, Applied Measurement Systems attempts to provide a comprehensive presentation and in-depth guidance on some of the key applied and advanced topics in measurements for scientists, engineers and educators

Study of advanced communications satellite systems based on SS-FDMA

A satellite communication system based on the use of a multiple, contiguous beam satellite antenna and frequency division multiple access (FDMA) is studied. Emphasis is on the evaluation of the feasibility of SS (satellite switching) FDMA technology, particularly the multiple, contiguous beam antenna, the onboard switch and channelization, and on methods to overcome the effects of severe Ka band fading caused by precipitation. This technology is evaluated and plans for technology development and evaluation are given. The application of SS-FDMA to domestic satellite communications is also evaluated. Due to the potentially low cost Earth stations, SS-FDMA is particularly attractive for thin route applications up to several hundred kilobits per second, and offers the potential for competing with terrestrial facilities at low data rates and over short routes. The onboard switch also provides added route flexibility for heavy route systems. The key beneficial SS-FDMA strategy is to simplify and thus reduce the cost of the direct access Earth station at the expense of increased satellite complexity

Intelligent Circuits and Systems

ICICS-2020 is the third conference initiated by the School of Electronics and Electrical Engineering at Lovely Professional University that explored recent innovations of researchers working for the development of smart and green technologies in the fields of Energy, Electronics, Communications, Computers, and Control. ICICS provides innovators to identify new opportunities for the social and economic benefits of society.　 This conference bridges the gap between academics and R&D institutions, social visionaries, and experts from all strata of society to present their ongoing research activities and foster research relations between them. It provides opportunities for the exchange of new ideas, applications, and experiences in the field of smart technologies and finding global partners for future collaboration. The ICICS-2020 was conducted in two broad categories, Intelligent Circuits & Intelligent Systems and Emerging Technologies in Electrical Engineering

MEMS enabled miniaturisation of photoacoustic imaging and sensing systems

This work presents multiple advances toward miniaturised photoacoustic imaging systems. Miniaturising the system is done in two steps. Firstly, by using novel custom arrays of piezoelectric miniaturised ultrasound transducers. The arrays were fabricated using a cost-efficient multi-user process. The achievable upper frequency limits were restricted by the design limitations of the multi-user process. The designs comprised of a single frequency and two frequency staggered arrays. They were characterised using laser Doppler velocimetry, pitch and catch technique as well as photoacoustic excitation. Additionally, the arrays were compared to commercial bulk ultrasound transducers. The custom-made PMUT arrays perform well compared to commercial transducer, despite their significantly smaller (two orders of magnitude) detection area. Secondly, an optical resolution photoacoustic microscope consisting consisting of MEMS based excitation - using a fast-scanning micro-mirror for Q-switching - and detection schemes is built and used to image synthetic targets and phantoms. Furthermore, a simulation model of the system is developed to evaluate influences of the miniaturised elements on the photoacoustic signal generation and received spectra and signal strength. Finally, a novel photoacoustic excitation scheme based on CW - laser excitation and a MEMS based fast-scanning micro-mirror is presented and its performance relative to pulsed excitation photoacoustic imaging is evaluated. Here, the photoacoustic excitation is not due to fast pulsed laser excitation, but caused by scanning a focused CW - beam over a sample.This work presents multiple advances toward miniaturised photoacoustic imaging systems. Miniaturising the system is done in two steps. Firstly, by using novel custom arrays of piezoelectric miniaturised ultrasound transducers. The arrays were fabricated using a cost-efficient multi-user process. The achievable upper frequency limits were restricted by the design limitations of the multi-user process. The designs comprised of a single frequency and two frequency staggered arrays. They were characterised using laser Doppler velocimetry, pitch and catch technique as well as photoacoustic excitation. Additionally, the arrays were compared to commercial bulk ultrasound transducers. The custom-made PMUT arrays perform well compared to commercial transducer, despite their significantly smaller (two orders of magnitude) detection area. Secondly, an optical resolution photoacoustic microscope consisting consisting of MEMS based excitation - using a fast-scanning micro-mirror for Q-switching - and detection schemes is built and used to image synthetic targets and phantoms. Furthermore, a simulation model of the system is developed to evaluate influences of the miniaturised elements on the photoacoustic signal generation and received spectra and signal strength. Finally, a novel photoacoustic excitation scheme based on CW - laser excitation and a MEMS based fast-scanning micro-mirror is presented and its performance relative to pulsed excitation photoacoustic imaging is evaluated. Here, the photoacoustic excitation is not due to fast pulsed laser excitation, but caused by scanning a focused CW - beam over a sample

Single-photon detectors for satellite based quantum communications

With the growing use of online communications in our modern society, information security is becoming a big concern. Along with that, the progress in quantum computers is posing severe threats to such communications. Once powerful quantum computers are available, most of today's encryption schemes, which are based on computationally hard problems, will be broken within a short period. Researchers are therefore making a great effort to establish quantum-safe encryption schemes. One such scheme is quantum key distribution (QKD), which utilizes the laws of quantum mechanics. These cryptography protocols offer unconditional security to the communication between two distant parties by providing a secure way of sharing encryption keys between them. While over the last few decades QKD has continuously progressed, it is limited to a distance of up to several hundred kilometers using terrestrial quantum links. Satellites are therefore being considered to extend the QKD range for global coverage, although implementations of the satellite-based QKD infrastructure are still in their early stage. There are many aspects of QKD that need further assessment and advancement for establishing long-term satellite-based quantum communication (QC). My thesis works were focused on developing advanced systems for single-photon detectors and quantum sources. Single-photon avalanche diodes (SPADs) are the most viable option for satellite-based quantum communications. They must travel to outer space either for receiving quantum-states in the ground-to-satellite QC or for characterizing the quantum-sources in the satellite-to-ground QC. However, while in space, SPADs exhibit damage caused by the space radiation that gradually increases their dark counts. Performing QKD is not possible when the dark counts exceed a specific threshold. Hence, methods of reducing the detectors' dark counts by mitigating the damages would help to extend the SPADs' in-space useful lifetime. Laser annealing is one such effective method, found in lab experiments, to heal the radiation-induced detector damages. We now aim to carry out this method in low Earth orbit (LEO) to verify its in-orbit effectiveness. On that goal, we are building an annealing payload (APL) for a cube satellite (CubeSat) in collaboration with the University of Illinois at Urbana Champaign (UIUC). We, the University of Waterloo team, built one of the two segments of the APL-- a space-qualified detector module containing two Excelitas C30902SH and Excelitas SLiK detectors. Our miniaturized and compact module integrates the facilities required for the detector operation and laser annealing, as well as an active detector temperature control system. The operation of the detector module is highly flexible and software controllable. Our detector module will work together with the control board containing the laser annealing system (built by the UIUC team). Once the satellite has been launched in 2020, the in-orbit experiment will enable us to study the in-space SPAD radiation damage and their healing using the integrated annealing system. During a second project, we designed and built a new simple readout circuit for the negative feedback avalanche diodes (NFADs), which are free-running single-photon detectors at telecom wavelengths. These detectors suffer from strong afterpulsing effects, which limits their overall performances. Therefore, our readout system incorporates features to suppress NFAD afterpulses. We also used this custom readout to characterize two NFADs (from Princeton Lightwave) and assessed the performance of the new electronics. Our analysis showed that even at higher detection efficiencies, a 20 $\mu$s hold-off time after each avalanche event is enough to extensively reduce the number of afterpulses and to keep the dark count rate below 100 Hz at 192 K temperature. Both the detectors showed timing jitter of less than 75 ps FWHM at their maximum efficiencies. The best figure of merit is found to be 1.6$\times 10^7$, which is comparable to that of the high-performing superconducting nanowire single-photon detectors. This result demonstrates the suitability of our readout and the NFADs in various quantum optics applications, such as in long-distance quantum key distribution, where the detection rate is usually low. We then performed a blinding attack, which enables an Eavesdropper in QKD to gain information on the key, on these NFADs using bright illumination. These detectors are usually threshold detectors that generate a click when the optical power is above a certain threshold, otherwise they do not click. Blinding attack utilizes detectors' inability to resolve the photon numbers. During the experiment, we sent controlled optical pulses with a high time resolution to deterministically force detection at the detectors. The result demonstrated the NFADs' susceptibility to these attacks, which tells us to include countermeasures into the system to protect the communications. Finally, we built a quantum source to produce 785 nm polarized photons to implement decoy-state BB84 QKD. Our source utilized the sum-frequency generation scheme to generate 785 nm laser pulses. Its modulator system includes an intensity modulator and two-phase modulators in the Mach-Zehnder configuration to prepare polarized quantum states with different intensities. Our source provides a repetition rate of 500 MHz, which was successfully used in an airborne QKD demonstration with a moving receiver up to $10~ km$ distance. To summarize, my research projects are a contribution to the development of advanced devices, particularly single-photon detectors for quantum communications

One way Doppler extractor. Volume 1: Vernier technique

A feasibility analysis, trade-offs, and implementation for a One Way Doppler Extraction system are discussed. A Doppler error analysis shows that quantization error is a primary source of Doppler measurement error. Several competing extraction techniques are compared and a Vernier technique is developed which obtains high Doppler resolution with low speed logic. Parameter trade-offs and sensitivities for the Vernier technique are analyzed, leading to a hardware design configuration. A detailed design, operation, and performance evaluation of the resulting breadboard model is presented which verifies the theoretical performance predictions. Performance tests have verified that the breadboard is capable of extracting Doppler, on an S-band signal, to an accuracy of less than 0.02 Hertz for a one second averaging period. This corresponds to a range rate error of no more than 3 millimeters per second

Ultra Wideband

Ultra wideband (UWB) has advanced and merged as a technology, and many more people are aware of the potential for this exciting technology. The current UWB field is changing rapidly with new techniques and ideas where several issues are involved in developing the systems. Among UWB system design, the UWB RF transceiver and UWB antenna are the key components. Recently, a considerable amount of researches has been devoted to the development of the UWB RF transceiver and antenna for its enabling high data transmission rates and low power consumption. Our book attempts to present current and emerging trends in-research and development of UWB systems as well as future expectations