This dissertation introduces new technologies and techniques for low-cost phased arrays and scanning antennas. Special emphasis is placed on new approaches for low-cost millimeter-wave beam control. Several topics are covered. A novel reconfigurable grating antenna is presented for low-cost millimeter-wave beam steering. The versatility of the approach is proven by adapting the design to dual-beam and circular-polarized operation. In addition, a simple and accurate procedure is developed for analyzing these antennas. Designs are presented for low-cost microwave/millimeter-wave phased-array transceivers with extremely broad bandwidth. The target applications for these systems are mobile satellite communications and ultra-wideband radar. Monolithic PIN diodes are a useful technology, especially suited for building miniaturized control components in microwave and millimeter-wave phased arrays. This dissertation demonstrates a new strategy for extracting bias-dependent small-signal models for monolithic PIN diodes. The space solar-power satellite (SPS) is a visionary plan that involves beaming electrical power from outer space to the earth using a high-power microwave beam. Such a system must have retrodirective control so that the high-power beam always points on target. This dissertation presents a new phased-array architecture for the SPS system that could considerably reduce its overall cost and complexity. In short, this dissertation presents technologies and techniques that reduce the cost of beam steering at microwave and millimeter-wave frequencies. The results of this work should have a far-ranging impact on the future of wireless systems.

This thesis presents the concept of a "distributed HVDC converter" for offshore wind farms. The proposed converter topology allows series interconnection of wind turbines obviating the necessity of transformers and an offshore platform. Each wind turbine is equipped with a 5MW permanent-magnet synchronous generator and an ac-dc-dc converter. The converter topology is a diode rectifier (ac-dc) cascaded with a single-switch step-down converter (dc-dc). The dc-dc stage allows the current to flow at all times in the dc link while regulating generator torque. The receiving end is equipped with a conventional thyristor-based HVDC converter. The inverter station is located onshore and it regulates the dc link current to be constant. Stability of the configuration and independent operation of the wind turbines are validated through simulations using the PSCAD/EMTDC software package. Protection for some key dc fault scenarios are discussed and a possible protection strategy is proposed.

This thesis presents the concept of a "distributed HVDC converter" for offshore wind farms. The proposed converter topology allows series interconnection of wind turbines obviating the necessity of transformers and an offshore platform. Each wind turbine is equipped with a 5MW permanent-magnet synchronous generator and an ac-dc-dc converter. The converter topology is a diode rectifier (ac-dc) cascaded with a single-switch step-down converter (dc-dc). The dc-dc stage allows the current to flow at all times in the dc link while regulating generator torque. The receiving end is equipped with a conventional thyristor-based HVDC converter. The inverter station is located onshore and it regulates the dc link current to be constant. Stability of the configuration and independent operation of the wind turbines are validated through simulations using the PSCAD/EMTDC software package. Protection for some key dc fault scenarios are discussed and a possible protection strategy is proposed.

No description available.

Long resistive cables used in the operation of remote instrumentation impose fundamental limits on the amount of power delivered and create difficulties in voltage regulation at the remote-end (voltage at the end of the cable) with changing load conditions. This type of power delivery is used in many engineering systems such as in the operation of underwater remotely-operated vehicles, in oil drilling and mining industries, and in highly distributed systems (aircraft, submarines, and space stations, etc.). The focus of this research is to develop new approaches for power delivery in systems that have considerable voltage drops between the local and remote-ends.Two novel methods of power delivery based on state feedback control and parallel operation of switching and linear regulators to enhance stability and increase the power delivered at the remote-end are developed and validated experimentally.A system-level approach is developed to control the remote-end voltage for changing load conditions through the usage of a model inversion technique at the local-end along with a feedback of the local-end variables.

This research investigates partial discharge phenomena of on-site power transmission cables of 69 kV and 161 kV by inspecting the data measured under various environments. Effective procedures and methods are suggested for estimating insulation condition of power transmission cables. To tackle the problem of interference of the environmental noises to the on-site power transmission cables, a detection method is presented based on the relationship among the amplitude, phase, and focused area of electrical signals. The difference between the outer and inner electrical signals in power transmission cable is analyzed to improve the accuracy of pattern recognition. In addition, the insulation conditions of the cable joint and the cable terminator are evaluated by comparing results of electrical and non-electrical detections. Finally, a standard procedure with some key points of inspection processes under various environments is suggested to evaluate the cable insulation degradation based on the inspection data obtained from various environments.

In the past decade, artificial materials have attracted considerable attention as potential solutions to meet the demands of modern microwave technology for simultaneously achieving component minimization and higher performance in mobile communications, medical, and optoelectronics applications. To realize this potential, more research on metamaterials is needed. In this dissertation, new bandpass filter and diplexer as microwave metamaterial applications have been developed. Unlike the conventional complementary split ring (CSRR) filters, coupled lines are used to provide larger coupling capacitance, resulting in better bandpass characteristics with two CSRRs only. The modified bandpass filters are used to deisgn a compact diplexer. A new CSRR antenna fed by coplanar waveguide has also been developed as another metamaterial application. The rectangular shape CSRRs antenna achieves dual band frequency properties without any special matching network. The higher resonant frequency is dominantly determined by the outer slot ring, while the lower resonant frequency is generated by the coupling between two CSRRs. The proposed antenna achieves about 35 percent size reduction, compared with the conventional slot antennas at the low resonant frequencies. As a future alternative energy solution, space solar power transmission and wireless power transmission have received much attention. The design of efficient rectifying antennas called rectennas is very critical in the wireless power transmission system. The conventional method to obtain long distance range and high output power is to use a large antenna array in rectenna design. However, the use of array antennas has several problems: the relatively high loss of the array feed networks, difficultiy in feeding network design, and antenna radiator coupling that degrades rectenna array performance. In this dissertation, to overcome the above problems, a reflectarray is used to build a rectenna system. The spatial feeding method of the reflectarray eliminates the energy loss and design complexity of a feeding network. A high gain rectifying antenna has been developed and located at the focal point of the reflectarray to receive the reflected RF singals and genterate DC power. The technologies are very useful for high power wireless power transmission applications.

This dissertation introduces new technologies and techniques for low-cost phased arrays and scanning antennas. Special emphasis is placed on new approaches for low-cost millimeter-wave beam control. Several topics are covered. A novel reconfigurable grating antenna is presented for low-cost millimeter-wave beam steering. The versatility of the approach is proven by adapting the design to dual-beam and circular-polarized operation. In addition, a simple and accurate procedure is developed for analyzing these antennas. Designs are presented for low-cost microwave/millimeter-wave phased-array transceivers with extremely broad bandwidth. The target applications for these systems are mobile satellite communications and ultra-wideband radar. Monolithic PIN diodes are a useful technology, especially suited for building miniaturized control components in microwave and millimeter-wave phased arrays. This dissertation demonstrates a new strategy for extracting bias-dependent small-signal models for monolithic PIN diodes. The space solar-power satellite (SPS) is a visionary plan that involves beaming electrical power from outer space to the earth using a high-power microwave beam. Such a system must have retrodirective control so that the high-power beam always points on target. This dissertation presents a new phased-array architecture for the SPS system that could considerably reduce its overall cost and complexity. In short, this dissertation presents technologies and techniques that reduce the cost of beam steering at microwave and millimeter-wave frequencies. The results of this work should have a far-ranging impact on the future of wireless systems.

This thesis proposes a novel technique using a phase-lock loop (PLL) style phase control loop to achieve retrodirective phased array antenna steering. This novel approach introduces the concept of phase scaling and frequency translation. It releases the retrodirective transmit-receive frequency ratio from integer constraints and avoids steering approximation errors. The concept was developed to achieve automatic and precise beam steering for the solar power satellite (SPS). The testing was performed using a transceiver converting a pair of received 2.9 GHz signals down to 10 MHz, and up converting two 10 MHz signals to 5.8 GHz. Phase scaling and conjugation was performed at the 10 MHz IF using linear XOR phase detectors and a PLL loop to synthesize a 10 MHz signal with conjugate phase. A phase control loop design is presented using PLL design theory achieving a full 2π steering range. The concept of retrodirective beam steering is also presented in detail. Operational theory and techniques of the proposed method are presented. The prototype circuit is built and the fabrication details are presented. Measured performance is presented along with measurement techniques. Pilot phase detectors and PCL achieve good linearity as required. The achieved performance is benchmarked with standards derived from likely performance requirements of the SPS and beam steering of small versus large arrays are considered.

In conventional design of power delivery networks (PDNs), the PDN impedance is required to be less than the target impedance over the frequency range of interest to minimize the IR drop and to suppress the inductive noise during data transitions. As a result, most PDNs in high-speed systems consist of power and ground planes to provide a low-impedance path between the voltage regulator module (VRM) and the integrated circuit (IC) on the printed circuit board (PCB). For off-chip signaling, charging and discharging signal transmission lines induce return currents on the power and ground planes. The return current always follows the path of least impedance on the reference plane closest to the signal transmission line. The return current path plays a critical role in maintaining the signal integrity of the bits propagating on the signal transmission lines. The problem is that the disruption between the power and ground planes induces return path discontinuities (RPDs), which create displacement current sources between the power and ground planes. The current sources excite the plane cavity and cause voltage fluctuations. These fluctuations are proportional to the plane impedance since the current is drawn through the PDN by the driver. Therefore, low PDN impedance is required for power supply noise reduction. Alternatively, methods of preventing RPDs can be used to suppress power supply noise. Using a power transmission line (PTL) eliminates the discontinuity between the power and ground planes, thereby preventing the RPD effects. In this approach, transmission lines replace the power plane for conveying power from the VRM to each IC on the PCB. The PTL-based PDN enables both power and signal transmission lines to be referenced to the same ground plane so that a continuous current path can be formed, unlike the power-plane-based PDN. As a result, a closed current loop is achieved, and the voltage fluctuation caused by RPDs is removed in idealistic situations. Without the RPD-related voltage fluctuation, reducing the PDN impedance is not as critical as in the power-plane-based approach. Instead, the impedance of the PTL is determined by the impedance of the signaling circuits. To use the PTL-based PDN in a practical signaling environment, several issues need to be solved. First, the dc drop coming from the source termination of the PTL needs to be addressed. The driver being turned on and off dictates the current flow through the PTL, causing the dc drop to be dynamic, which depends on the data pattern. Second, impedance mismatch between the PTL and termination can occur due to manufacturing variations. Third, an increase in the number of PCB traces should be addressed by devising a method to feed more than one driver with one PTL. Lastly, the power required to transmit 1 bit of data should be optimized for the PTL by using a new signaling scheme and adjusting the impedance of the signaling circuit. Constant flow of current through the PDN is one solution proposed to address the first two issues. Constant current removes the dynamic characteristics of the dc drop by inducing a fixed amount of dc drop over the PTL. Moreover, constant current keeps the PTL fully charged at all times, and thereby eliminates the process of repeatedly charging and discharging the power transmission line. The constant current PTL (CCPTL) scheme maintains constant current flow regardless of the input data pattern. Early results on the CCPTL scheme have been discussed along with the measurements. The CCPTL scheme severs the link between the current flowing through the PTL and the output data of the I/O driver connected to it. Also, it eliminates the charging and discharging process of the PTL, thereby completely eliminating power supply noise in idealistic situations. To reduce any associated power penalty, a pseudo-balanced PTL (PBPTL) scheme is also proposed using the PTL concept. A pseudo-balanced (PB) signaling scheme, which uses an encoding technique to map N-bit data onto M-bit encoded data with fixed number of 1s and 0s, is applied. When the PB signaling scheme is combined with the PTL, the jitter performance improves significantly as compared to currently practiced design approach.