A Review: Substrate Integrated Waveguide Antennas and Arrays

This study aims to provide an overview and deployment of Substrate-Integrated Waveguide (SIW) based antenna and arrays, with different configurations, feeding mechanisms, and performances. Their performance improvement methods, including bandwidth enhancement, size reduction, and gain improvement are also discussed based on available literature. SIW technology, which acts as a bridge between planar and non-planar technology, is a very favorable candidate for the development of components operating at microwave and millimeter wave band. Due to this, SIW antennas and array take the advantages of both classical metallic waveguide, which includes high gain, high power capacity, low cross polarization, and high selectivity, and that of planar antennas which comprises low profile, light weight, low fabrication cost, conformability to planar or bent surfaces, and easy integration with planar circuits

Bandwidth Enhancement of Substrate Integrated Waveguide Cavity-backed Bow-tie-complementary-ring-slot Antenna using a Shorted-via

In this study, a planar cavity-backed bow-tie-complementary-ring-slot antenna is proposed, and a new approach for bandwidth enhancement using a shorted-via is introduced. A shorted-via concept overcomes the narrow impedance bandwidth of a conventional substrate integrated waveguide cavity-backed antenna. By adjusting the location of the shorted-via (placed just above the centroid of the radiating slot), the individual bandwidth of the lower and higher order resonances has been tuned below -10 dB criterion, which results in the broadening of the bandwidth. Finally, the antenna is proficient to operate for an impedance bandwidth of 15.71 per cent, ranging from 12.02~14.07 GHz. The proposed antenna shows a gain of better than 4 dBi within the operating band with less than 0.5 dBi variation. Moreover, the antenna preserves good radiation characteristics, which is similar to that of the conventional metallic counterpart. To validate the simulated results, an antenna is fabricated and tested. The simulated results in terms of the reflection coefficient, gain, and radiation patterns are in good agreement with the measured results

PV ENABLED NET ZERO EV CHARGING STATION: SYSTEM DESIGN AND SIMULATION STUDY

A paradigm shift in the transportation sector is being witnessed due to resurgence of electric vehicles (EVs). They are ideally considered to be non-polluting and eco-friendly, however it has its own demerits of overloading existing grid infrastructure and, could significantly contribute towards carbon emissions depending on the source used for charging them. The ideal solution to counteract the critical shortcomings is by developing a charging infrastructure integrated with renewable energy technology. The main aim of this thesis is to design such a charging station coupled with solar energy for urban cities. Simplified EV load models are developed by considering most popular commercial EV in the market. The designed solar powered charging station is tested with the developed EV load models and, would be located in selected urban cities within Ontario. Firstly, literature review on effects of EV charging directly from grid, benefits of EV charging with renewables, and amalgamation of EV charging with Net Zero (NZ) concepts is introduced. Later, three types of system architectures are studied for solar powered charging station. Selection of architecture for this work is done considering the economics of installation, and operation. Optimization in design of solar powered charging station is presented by varying the power ratio and, obtaining the annual energy yield for different types of orientation considering all EV load models. Then, NZ Photovoltaic (PV) enabled charging station is designed and, is tested with selected load models and, energy economic analysis is done for all designs. Finally, recommendations are made encompassing the selection of net-zero based charging stations along with economic considerations and its short and long term effects on environment

H.264 Decoder: A Case Study in Multiple Design Points

H.264, a state-of-the-art video compression standard, is used across a range of products from cell phones to HDTV. These products have vastly different performance, power and cost requirements, necessitating different hardware-software solutions for H.264 decoding. We show that a de-sign methodology and associated tools which support syn-thesis from high-level descriptions and which allow mod-ular refinement throughout the design cycle, can share the majority of design effort across multiple design points. Us-ing Bluespec SystemVerilog, we have created a variety of designs for the H.264 decoder tuned to support decod-ing at resolutions ranging from QCIF video (176 × 14

Human Evaluation of Text-to-Image Models on a Multi-Task Benchmark

We provide a new multi-task benchmark for evaluating text-to-image models. We perform a human evaluation comparing the most common open-source (Stable Diffusion) and commercial (DALL-E 2) models. Twenty computer science AI graduate students evaluated the two models, on three tasks, at three difficulty levels, across ten prompts each, providing 3,600 ratings. Text-to-image generation has seen rapid progress to the point that many recent models have demonstrated their ability to create realistic high-resolution images for various prompts. However, current text-to-image methods and the broader body of research in vision-language understanding still struggle with intricate text prompts that contain many objects with multiple attributes and relationships. We introduce a new text-to-image benchmark that contains a suite of thirty-two tasks over multiple applications that capture a model's ability to handle different features of a text prompt. For example, asking a model to generate a varying number of the same object to measure its ability to count or providing a text prompt with several objects that each have a different attribute to identify its ability to match objects and attributes correctly. Rather than subjectively evaluating text-to-image results on a set of prompts, our new multi-task benchmark consists of challenge tasks at three difficulty levels (easy, medium, and hard) and human ratings for each generated image.Comment: NeurIPS 2022 Workshop on Human Evaluation of Generative Models (HEGM

Bipolar large-signal modeling and power amplifier design

Ph.D.Joy Laska

Image segmentation for depth region identification

Several recent applications require landscape photographs to be divided into depth- regions (foreground, middleground, background, sky). Currently, this segmentation is done manually, since depth-perception is itself a very subjective area, and none of the recent advances in image segmentation cater specifically to the unique features of depth-planes in landscapes. A method to automate or semi-automate this segmentation would make these applications considerably less cumbersome, especially in areas where large volumes of images are to be analysed. This project explores the theory behind depth perception, the recent research done on landscape photographs and the currently dominant segmentation approaches, and proposes a method to effect depth-segmentation in landscape photographs. The proposed method isolates specific image attributes of interest to landscapes, such as inter-region contrast, intra-region contrast, lightness, saturation and hue, to arrive at effective parameters to identify these depth planes. This project also explores techniques that could enhance the segmentation results of the proposed method and presents the performance analysis from the evaluation of those techniques.Bachelor of Engineerin

Guanosine tetraphosphate-induced dissociation of open complexes at the Escherichia coli ribosomal protein promoters rplJ and rpsA P1: nanosecond depolarization spectroscopic studies

We have measured the fluorescence anisotropy decays of various transcription complexes formed between Escherichia coli RNA polymerase (RNAP) and the rplJ, rpsA P1 and lacUV5 promoters, where the &#963;<SUP>70</SUP>-subunit of RNAP is covalently labeled with the fluorescent probe 1,5-IAEDANS. The observed changes in the rotational correlation times (&#966;<SUB>r</SUB>) of the &#963;<SUP>70</SUP>-bound probe upon ppGpp or NTP addition to preformed open complexes, were used to directly infer the extent of association of the &#963;-subunit with these transcription complexes. At the rplJ and rpsA P1 promoters, the addition of ppGpp (in the absence of heparin and nucleotides), results in the dissociation of RNAP from the binary complex. This is either accompanied by, or leads to the dissociation of a fraction of the holoenzyme-bound &#963;<SUP>70</SUP>. At the lacUV5 promoter, only a marginal dissociation of RNAP is observed. We propose a model where two types of ppGpp-bound RNAP interact with the ribosomal protein promoters. One is transcription-competent and releases &#963;<SUP>70</SUP> upon elongation, while the other dissociates from the open complex. A fraction of the latter species releases the &#963;<SUP>70</SUP> subunit and is unable to form a transcription-competent holoenzyme. Our data supports the mechanism of open complex-destabilization at stringent promoters by ppGpp

Modeling and design techniques for RF power amplifiers

The book covers RF power amplifier design, from device and modeling considerations to advanced circuit design architectures and techniques. It focuses on recent developments and advanced topics in this area, including numerous practical designs to back the theoretical considerations. It presents the challenges in designing power amplifiers in silicon and helps the reader improve the efficiency of linear power amplifiers, and design more accurate compact device models, with faster extraction routines, to create cost effective and reliable circuits