Indiana University-Purdue University Indianapolis (IUPUI) / This thesis is an examination of one of the main technologies to be developed on the path to Space Solar Power (SSP): Wireless Power Transfer (WPT), specifically power beaming. While SSP has been the main motivation for this body of work, other applications of power beaming include ground-to-ground energy transfer, ground to low-flying satellite wireless power transfer, mother-daughter satellite configurations, and even ground-to-car or ground-to-flying-car power transfer. More broadly, Wireless Power Transfer falls under the category of radio and microwave signals; with that in mind, some of the topics contained within can even be applied to 5G or other RF applications. The main components of WPT are signal transmission, propagation, and reception. This thesis focuses on the transmission and propagation of wireless power signals, including beamforming with Phased Array Antennas (PAAs) and evaluations of transmission and propagation efficiency. Signals used to transmit power long distances must be extremely directive in order to deliver the power at an acceptable efficiency and to prevent excess power from interfering with other RF technology. Phased array antennas offer one method of increasing the directivity of a transmitted beam through off-axis cancellation from the multi-antenna source. Besides beamforming, another focus of this work is on the equations used to describe the efficiency and far field distance of transmitting antennas. Most previously used equations, including the Friis equation and the Goubau equation, are formed by examining singleton antennas, and do not account for the unique properties of antenna arrays. Updated equations and evaluation methods are presented both for the far field and the efficiency of phased array antennas. Experimental results corroborate the far field model and efficiency equation presented, and the implications of these results regarding space solar power and other applications are discussed. The results of this thesis are important to the applications of WPT previously mentioned, and can also be used as a starting point for further WPT and SSP research, especially when looking at the foundations of PAA technology.

No description available.

The Finite-Difference Time-Domain (FDTD) method has gained tremendous popularity in the past decade as a tool for solving Maxwell's equations. Phased Array Antennas find several applications including mobile communications ( cellular, personal communication systems and networks), satellite communications, global positioning system (GPS), aeronautical and radar systems. This dissertation describes the application of the FDTD method for calculating broadband characteristics of finite-sized phased array antennas consisting of microstrip elements fed with coaxial probes. The characterization of such antennas is dependent upon the development of simulation tools that can accurately model general topologies including wires, dielectrics, conductors lumped elements and metallic strips. The use of these simulation tools reduces the cost and effort associated with fabricating and testing phased array antennas. The FDTD formulation is inherently broadband, very general, and easily accorrunodates arbitrary conductor geometry and dielectric configurations. The FDTD method is implemented and applied to determine the input impedance, radiation-patterns and gain of microstrip antennas. Next, the main contributions of this work are described which include the full time-domain characterization of broadband characteristics of finite-sized phased array antennas for different scan conditions. Active reflection coeffici nt gain scan-element patterns and scanning-array radiation patterns are calculated.

Silicon photonics is leading the advent of very-large-scale photonic integrated circuits (PICs) in which lasers, modulators, photodetectors, and multiplexers are integrated on a single chip and synchronized to enable faster data transfer both between and within highly integrated chips. Silicon photonics now extends beyond communication applications, paving new paths for many emerging applications and holding great potential in creating a compact beam projector. Compact beam steering in the visible and near-infrared spectral range is required for emerging applications such as augmented reality (AR) and virtual reality (VR) displays, optical traps for quantum information processing, biosensing, light detection and ranging (LiDAR), and free-space optical communications (FSO). Here we discuss two novel integrated beam steering platforms in the visible and near-infrared wavelengths, optical phased array (OPA) and focal plane switch array (FPSA), that can shape and steer a light beam. Previous OPA demonstrations have been mainly limited to the near-infrared spectral range due to the fabrication and material challenges imposed by the smaller wavelengths. Here we present the first active blue light phased array at the wavelength of 488 nm, leveraging a high confinement silicon nitride (Si₃N₄) platform. We randomly and sparsely place the emitters to remove grating lobes, alleviate fabrication constraints at this short wavelength and achieve a wide-angle 1D beam steering over a 50° field of view (FoV) with a full width at half maximum (FWHM) beam size of 0.17°. This demonstration is a crucial first step in realizing a non-mechanical fully-integrated beam steering device for many emerging applications. Unlike 1D steering OPA, designing 2D OPA impose a different challenge. Numerous issues arise, including complicated waveguide routing and optical crosstalk between channels. Also, creating a highly directional beam without ghost images is required to deploy visible OPAs in emerging applications. However, current demonstrations of visible OPAs, including our first demonstration, suffer from the issue of low directionality due to the presence of grating lobes, high background noise and a low percentage of power in the main beam. We demonstrate an integrated OPA that generates a highly directional beam at blue wavelengths (488 nm) by leveraging a disordered hyperuniform distribution of emitters. This exotic distribution is found in birds’ cone photoreceptor arrangements, the most uniform sampling given intrinsic packing constraints. Such unique distribution allows us to mitigate fabrication and waveguide routing constraints and achieve a beam with low background noise, high percentage of power and no grating lobes. Large-scale integration of the platform enables fully reconfigurable high-efficiency light projection across the entire visible spectrum. The novel platform offers a viable platform for next-generation applications in visible-spectrum addressing, imaging, and scanning displays. Although OPA is an invaluable device for creating a highly directional beam on a chip-scale, OPA has an inherent power consumption issue. Its architecture requires simultaneous control of all the phase shifters in the system for operation. We propose a novel silicon photonics FPSA system for beam steering with orders of magnitude lower electrical power consumption than other state-of-the-art platforms. The demonstrated system operates in the near-infrared wavelength regime; however, this can be extended into different wavelengths. Our demonstration enables low-size, weight, and power (SWaP) LiDAR for precision and autonomous robotics and optical scanners for mobile devices.

Yes / This article presents a unique technique to enhance isolation between transmit/receive radiating elements in densely packed array antenna by embedding a metamaterial (MTM) electromagnetic bandgap (EMBG) structure in the space between the radiating elements to suppress surface currents that would otherwise contribute towards mutual coupling between the array elements. The proposed MTM-EMBG structure is a cross-shaped microstrip transmission line on which are imprinted two outward facing E-shaped slits. Unlike other MTM structures there is no short-circuit grounding using via-holes. With this approach, the maximum measured mutual coupling achieved is -60 dB @ 9.18 GHz between the transmit patches (#1 & #2) and receive patches (#3 & #4) in a four-element array antenna. Across the antenna’s measured operating frequency range of 9.12 to 9.96 GHz, the minimum measured isolation between each element of the array is 34.2 dB @ 9.48 GHz, and there is no degradation in radiation patterns. The average measured isolation over this frequency range is 47 dB. The results presented confirm the proposed technique is suitable in applications such as synthetic aperture radar (SAR) and multiple-input multiple-output (MIMO) systems. / H2020-MSCA-ITN-2016 SECRET-722424 and the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E0/22936/1

The need for a wide bandwidth array is introduced and explained. Basic planar array principles are reviewed as well as previous work performed on wide bandwidth planar array design. An Archimedean spiral is suggested for the array element and a model for the element radiation pattern is presented. A wide bandwidth linear array is then analyzed using the element model. The array is made to operate over a two octave bandwidth by using an alternate number of elements. This idea is then extended to two dimensions to form a wide bandwidth planar array design. An improved array design is then suggested using fewer elements. This array was fabricated and tested and showed close agreement to theoretically predicted radiation patterns. / M.S.

Approved for public release, distribution is unlimited / This thesis is a continuation of the design and development of a three-dimensional 2.4 GHz digital phased array radar antenna. A commercial off-the-shelf quadrature modulator and demodulator were used as phase shifters in the digital transmit and receive arrays. The phase response characteristic of the demodulator was measured and the results show that the phase difference between the received phase and transmit phase is small. In order to increase the bandwidth of the phased array, a method of time-varying phase weights for linear frequency modulated signal was investigated. Using time-varying phase weights on transmit and receive give the best performance, but require the range information of the target. It is more practical to use time-varying phase weights on only one side (transmit or receive but not both), and constant phase weights on the other side. The simulation results showed that by using time-varying phase weights, the matched filter loss is not as severe as it is when using the conventional fixed weights technique. It was also found that this method is only effective for small scan angles when the time-bandwidth product is large. The approach to implement time-varying phase weights on transmit using commercial components such as direct digital synthesizer and quadrature modulator is discussed. / Civilian, Ministry of Defense, Singapore

In this study, the Dual Beam Phased Array Antenna System designed for COST260* project is upgraded to have the abilities of beam steering, tracking and direction finding by providing the necessary computer codes using C++ Programming Language. The functions of new prototype are tested to verify the operation. *COST260 project was an adaptive phased array receiving antenna system for satellite communication, which was operating at 11.49-11.678 GHz band.

Research institutions around the globe are developing phased array feed (PAF) systems for wide-field L-band radio astronomical observations. PAFs offer faster survey speeds and larger fields of view than standard single-pixel feeds, which enable rapid sky surveys and significantly increased scientific capability. Because deep space astronomical signals are inherently weak, PAF systems must meet stringent noise and sensitivity requirements. Meeting these requirements requires detailed modeling of the phased array itself as well as the reflector it is mounted on. This thesis details a novel approach to dual-pol PAF design that models the array and reflector as a complete system in order to achieve a more optimal sensitivity and system noise temperature. The design and construction of two arrays designed using this technique is discussed. The implementation of a data acquisition system to receive data from the first of these arrays is also detailed. Polarization state information plays an important role in understanding cosmological processes for many deep space sources. Because of phase and gain imbalances in the LNAs and receiver chains calibration is required for accurate measurement of polarization by phased array feeds. As a result accurate polarimetric calibration techniques are essential for many observations. Existing polarimetric calibration methods are based on assumptions about the form of the system Mueller matrix that limit the generality of the method or require long observations of a polarized source which is time-consuming for multiple PAF beams. This thesis introduces a more efficient method of calibration that uses only three snapshot observations of bright astronomical calibrator sources, one unpolarized and two partially polarized. The design of an engineering array for the Green Bank Telescope is discussed. Measured results from a prototype element are presented along with simulated on-reflector results for the full array. Simulations predict that the array will be the highest sensitivity dual pol feed built by the Radio Astronomy Systems group at Brigham Young University to date.

A comprehensive study of the High-pass/Low-pass topology has been performed, increasing the understanding of error sources arising from bit layout issues and fabrication tolerances. This included a detailed analysis of error sources in monolithic microwave phase shifters due to device size limitations, inductor parasitics, loading effects, and non-ideal switches. Each component utilized in the implementation of a monolithic high-low pass phase shifter was analyzed, with its influence on phase behavior shown in detail. An emphasis was placed on the net impact on absolute phase variation, which is critical to the system performance of a phased array radar system. The design of the individual phase shifter filter sections, and the influence of bit ordering on overall performance was also addressed. A variety of X-band four- and five-bit phase shifters were fabricated in a 200 GHz SiGe HBT BiCMOS technology platform, and further served to validate the analysis and design methodology. The SiGe phase shifter can be successfully incorporated into a single-chip T/R module forming a system-on-a-chip (SoC). Reduction in the physical size of transmission lines was shown to be a possibility with spinel magnetic nanoparticle films. The signal transmission properties of phase lines treated with nanoparticle thin films were examined, showing the potential for significant size reduction in both delay line and High-pass/Low-pass phase topologies. Wide-band, low-loss, and near-hermetic packaging techniques for RF MEMS devices were presented. A thermal compression bonding technique compatible with standard IC fabrication techniques was shown, that uses a low temperature thermal compression bonding method that avoids plastic deformations of the MEMS membrane. Ultimately, a system-on-a-package (SoP) approach was demonstrated that utilized packaged RF MEMS switches to maintain the performance of the SiGe phase shifter with much lower loss. The extremely competitive performance of the MEMS-based High-pass/Low-pass phase shifter, despite the lack of the extensive toolkits and commercial fabrication facilities employed with the active-based SiGe phase shifters, confirms both the effectiveness of the detailed phase error analysis presented in this work and the robust nature of the High-pass/Low-pass topology.