KEY FRONT-END CIRCUITS IN MILLIMETER-WAVE SILICON-BASED WIRELESS TRANSMITTERS FOR PHASED-ARRAY APPLICATIONS

Millimeter-wave (mm-Wave) phased arrays have been widely used in numerous wireless systems to perform beam forming and spatial filtering that can enhance the equivalent isotropically radiated power (EIRP) for the transmitter (TX). Regarding the existing phased-array architectures, an mm-Wave transmitter includes several building blocks to perform the desired delivered power and phases for wireless communication. Power amplifier (PA) is the most important building block. It needs to offer several advantages, e.g., high efficiency, broadband operation and high linearity. With the recent escalation of interest in 5G wireless communication technologies, mm-Wave transceivers at the 5G frequency bands (e.g., 28 GHz, 37 GHz, 39 GHz, and 60 GHz) have become an important topic in both academia and industry. Thus, PA design is a critical obstacle due to the challenges associated with implementing wideband, highly efficient and highly linear PAs at mm-Wave frequencies. In this dissertation, we present several PA design innovations to address the aforementioned challenges. Additionally, phase shifter (PS) also plays a key role in a phased-array system, since it governs the beam forming quality and steering capabilities. A high-performance phase shifter should achieve a low insertion loss, a wide phase shifting range, dense phase shift angles, and good input/output matching.Ph.D

A Hybrid Method of Performing Electric Power System Fault Ride-Through Evaluations on Medium Voltage Multi-Megawatt Devices

This dissertation explores the design and analysis of a Hybrid Method of performing electrical power system fault ride-through evaluations on multi-megawatt, medium voltage power conversion equipment. Fault ride-through evaluations on such equipment are needed in order to verify and validate full scale designs prior to being implemented in the field. Ultimately, these evaluations will help in reducing the deployment risks associated with bringing new technologies into the marketplace. This is especially true for renewable energy and utility scale energy storage systems, where a significant amount of attention in recent years has focused on their ever increasing role in power system security and stability. The Hybrid Method couples two existing technologies together - a reactive voltage divider network and a power electronic variable voltage source - in order to overcome the inherent limitation of both methods, namely the short circuit duty required for implementation. This work provides the background of this limitation with respect to the existing technologies and demonstrates that the Hybrid Method can minimize the fault duty required for fault evaluations. The physical system, control objectives, and operation cycle of the Hybrid Method are analyzed with respect to the overall objective of reducing the fault duty of the system. A vector controller is designed to incorporate the time variant nature of the Hybrid Method operation cycle, limit the fault current seen by the power electronic variable voltage source, and provide regulation of the voltage at the point of common coupling with the device being evaluated. In order to verify the operation of both the Hybrid Method physical system and vector controller, a controller hardware-in-the-loop experiment is created in order to simulate the physical system in real-time against the prototype implementation of the vector controller. The physical system is simulated in a Real Time Digital Simulator and is controlled with the Hybrid Method vector controller implemented on a National Instruments FPGA. In order to evaluate the complete performance of the Hybrid Method, both a synchronous generator and a doubly-fed induction generator are modeled as the device under test in the simulations of the physical system. Finally, the results of the controller hardware-in-the-loop experiments are presented which demonstrate that the Hybrid Method is a viable solution to performing fault ride-through evaluations on multi-megawatt, medium voltage power conversion equipment

Program on application of communications satellites to educational development: Design of a 12 channel FM microwave receiver

The design, fabrication, and performance of elements of a low cost FM microwave satellite ground station receiver is described. It is capable of accepting 12 contiguous color television equivalent bandwidth channels in the 11.72 to 12.2 GHz band. Each channel is 40 MHz wide and incorporates a 4 MHz guard band. The modulation format is wideband FM and the channels are frequency division multiplexed. Twelve independent CATV compatible baseband outputs are provided. The overall system specifications are first discussed, then consideration is given to the receiver subsystems and the signal branching network

Design of a 12 channel fm microwave receiver

The design, fabrication, and performance of elements of a low cost FM microwave satellite ground station receiver is described. It is capable of accepting 12 contiguous color television equivalent bandwidth channels in the 11.72 to 12.2 GHz band. Each channel is 40 MHz wide and incorporates a 4 MHz guard band. The modulation format is wideband FM and the channels are frequency division multiplexed. Twelve independent CATV compatible baseband outputs are provided. The overall system specifications are first discussed, then consideration is given to the receiver subsystems and the signal branching network

Planar microwave filters with electronically tunability and other novel configurations

In order to meet the increasing demands of advance wireless communications and radar systems, several novel types of bandpass filters and bandstop filters have been developed in this thesis. A new type of varactor-tuned dual-mode bandpass filters have been presented to achieve a nearly constant absolute bandwidth over a wide tuning range by using a single DC bias circuit. Since the two operating modes (i.e., the odd and even modes) in a dualmode microstrip open-loop resonator do not couple to each other, tuning the passband frequency is accomplished by merely changing the two modal frequencies proportionally. Design equations and procedures are derived, and two two-pole tunable bandpass filters and a four-pole tunable bandpass filter of this type are demonstrated experimentally. Miniature microstrip doublet dual-mode filters that exhibit quasi-elliptic function response without using any cross coupling have been developed. It shows that a single two-pole filter or the doublet can produce two transmission zeros resulting from a double behaviour of the dual-mode resonator of this type. Electromagnetic (EM) simulation and experiment results of the proposed filters are described. Parallel feed configuration of a microstrip quasi-elliptic function bandpass filter has been built with a pair of open-loop dual-mode resonators. By employing this new coupling scheme, a novel filter topology with three-pole quasi-elliptic function frequency response can be obtained, leading to good passband performance, such as low insertion loss and good matching at the mid-band of passband. A designed three-pole bandpass filter of this type is demonstrated experimentally. A new class of dual-band filters based on non-degenerate dual-mode microstrip slow-wave open-loop resonators, which support two non-degenerate modes that do not couple, have been introduced. Different feed schemes that affect the filtering characteristics are investigated. Examples of dual-band filters of this type are described with simulation and experiment results. iii In order to achieve a wide spurious-free upper passband, a novel design of bandstop filter with cancellation of first spurious mode by using coupled three-section step impedance resonators (SIRs) has been developed. This cancellation occurs when two transmission poles coincide with the first spurious mode (transmission zero) by properly choosing the step impedance ratio and the gap between the SIR and the main transmission line. A stripline bandstop filter and a microstrip bandstop filter of this type are designed, fabricated and tested. As a preliminary investigation, the microstrip filter is tuned electronically using ferroelectric thin film varactors

Millimeter-Wave MMICs and Applications

As device technology improves, interest in the millimeter-wave band grows. Wireless communication systems migrate to higher frequencies, millimeter-wave radars and passive sensors find new solid-state implementations that promise improved performance, and entirely new applications in the millimeter-wave band become feasible. The circuit or system designer is faced with a new and unique set of challenges and constraints to deal with in order to use this portion of the spectrum successfully. In particular, the advantages of monolithic integration become increasingly important. This thesis presents many new developments in Monolithic Millimeter-Wave Integrated Circuits (MMICs), both the chips themselves and systems that use them. It begins with an overview of the various applications of millimeter waves, including a discussion of specific projects that the author is involved in and why many of them demand a MMIC implementation. In the subsequent chapters, new MMIC chips are described in detail, as is the role they play in real-world projects. Multi-chip modules are also presented with specific attention given to the practical details of MMIC packaging and multi-chip integration. The thesis concludes with a summary of the works presented thus far and their overall impact on the field of millimeter-wave engineering.</p

Surpassing Fundamental Limits through Time Varying Electromagnetics

Surpassing the fundamental limits that govern all electromagnetic structures, such as reciprocity and the delay-bandwidth-size limit, will have a transformative impact on all applications based on electromagnetic circuits and systems. For instance, violating principles of reciprocity enables non-reciprocal components such as isolators and circulators, which find application in full-duplex wireless radios, radar, biomedical imaging, and quantum computing systems. Overcoming the delay-bandwidth-size limit enables ultra-broadband yet extremely-compact devices whose size is not fundamentally related to the wavelength at the operating frequency. The focus of this dissertation is on using time-variance as a new toolbox to overcome these fundamental limits and re-imagine circuit and system design. Traditional non-reciprocal components are realized using ferrite materials that loose their reciprocity under the application of external magnetic bias. However, the sheer volume, cost and weight of these magnet based non-reciprocal components coupled with their inability to be fabricated in conventional semiconductor processes, have limited their application to bulky and large-scale systems. Other approaches such as active-biased and non-linearity based non-reciprocity are compatible with semiconductor processes, however, they suffer from other poor linearity and noise performance. In this dissertation, using passive transistor switch as the modulating element, we have proposed the concept of spatio-temporal conductivity modulation and have demonstrated a gamut of non-reciprocal devices ranging from gyrators to isolators and circulators. Through novel circuit topologies, for the first time, we have demonstrated on-chip circulators with multi-watt input power handling, operation at high millimeter-wave frequencies, and tailor made circulators for emerging technologies such as simultaneous-transmit-and-receive MRI and quantum computing. Delay-bandwidth-size trade-off is another fundamental electromagnetic limit, that constrains the delay imparted by a medium or a device within a fixed footprint to be inversely proportional to the signal bandwidth. It is this limit that governs the size of any microwave passive devices to be inversely proportional to its operating frequency. As a part of this dissertation, through intelligent clocking of switched capacitor networks we overcame the delay-bandwidth-size limit, thus resulting in infinitesimal, yet broadband microwave devices. Here we proposed a new paradigm in wave propagation where the properties such as the propagation delay and characteristic impedance does not depend on the constituent elements/materials of the medium, but rather heavily rely on the user-defined modulation scheme, thereby opening huge opportunities for realizing highly-reconfigurable passives. Leveraging these concepts, we demonstrated wide range of reciprocal an non-reciprocal devices including ultra-compact delay elements, highly-reconfigurable microwave passives, ultra-wideband circulators with infinitesimal form-factors and dispersion-free chip scale floquet topological insulators. Application of these devices have also been evaluated in real-world systems through our demonstrations of wideband, full-duplex receivers leveraging switched capacitors based true-time-delay interference cancelers and floquet topological insulator based antenna interfaces for full-duplex phased-arrays and ultra-wideband beamformers. Furthermore, to cater the growing RF and microwave needs of future, large-scale quantum computing systems, we demonstrated a low-cryogenic, wideband circulator based on time modulation of superconducting devices. This superconducting circulator is expected to operate alongside the superconducting qubits, inside a dilution refrigerator at 10mK-100mK, thus enabling a tightly integrated quantum system. We also presented the design and implementation of a cryogenic-CMOS clock driver chip that will generate the clocks required by the superconducting circulator. Finally, we also demonstrated the design and implementation of a low-noise, low power consumption, 6GHz - 8GHz cryogenic downconversion receiver at 4K for cryogenic qubit readout

Analysis and design considerations of resonator arrays for inductive power transfer systems

In the frame of inductive power transfer (IPT) systems, arrays of magnetically coupled resonators have received increasing attention as they are cheap and versatile due to their simple structure. They consist of magnetically coupled coils, which resonate with their self-capacitance or lumped capacitive networks. Of great industrial interest are planar resonator arrays used to power a receiver that can be placed at any position above the array. A thorough circuit analysis has been carried out, first starting from traditional two-coil IPT devices. Then, resonator arrays have been introduced, with particular attention to the case of arrays with a receiver. To evaluate the system performance, a circuit model based on original analytical formulas has been developed and experimentally validated. The results of the analysis also led to the definition of a new doubly-fed array configuration with a receiver that can be placed above it at any position. A suitable control strategy aimed at maximising the transmitted power and the efficiency has been also proposed. The study of the array currents has been carried out resorting to the theory of magneto-inductive waves, allowing useful insight to be highlighted. The analysis has been completed with a numerical and experimental study on the magnetic field distribution originating from the array. Furthermore, an application of the resonator array as a position sensor has been investigated. The position of the receiver is estimated through the measurement of the array input impedance, for which an original analytical expression has been also obtained. The application of this sensing technique in an automotive dynamic IPT system has been discussed. The thesis concludes with an evaluation of the possible applications of two-dimensional resonator arrays in IPT systems. These devices can be used to improve system efficiency and transmitted power, as well as for magnetic field shielding