RF Power Harvesting Rectenna

Sustainability is one of today\u27s primary engineering objectives. This principle involves system design that minimizes environmentally harmful energy emissions and resource consumption, and maximizes renewable energy practices [1]. Communication antennas transmit wireless signals that can be converted into usable energy. The Rectenna system described in this report, shown in Figure 1, was designed to accomplish this energy conversion, with -5dBm (316µW) minimum power at the rectifier input. Since typical ambient signal power is in the -70dBm (0.1nW) range, the proposed system could only convert passive, relatively high-power microwave band AC signals to DC. The Rectenna system was designed for 1.9GHz signal reception; however, the greatest ambient 1.9GHz signal power measured in Cal Poly’s Microwave Lab was in the -75dBm (31pW) to -70dBm (100pW) range, shown in Table 1. The team provided an external 1.9GHz source (-20dBm to 3dBm) to verify the design. An inset-fed microstrip patch is used as an energy harvesting antenna; the single patch was then arrayed into a 2x2 planar configuration. The designed patch antenna array has a 3dB larger gain, and 1% increased frequency bandwidth compared to the single patch. However, it is unable to harvest sufficient RF power for energy storage. When capturing multiple-source ambient RF signals, an omnidirectional antenna (captures energy in all directions) should be implemented, rather than a directional patch antenna array. The Greinacher rectifier [2] converts RF energy into usable DC power which is multiple times the input RF peak voltage. Simulations show the Greinacher rectifier output voltage is a function of the number of stages and peak input voltage. The antenna and rectifier are matched with |S11| less than -21dB and -5dB, respectively, at 1.9GHz to mitigate power losses. A high-efficiency Main Boost Converter (BQ25504) increases rectifier output DC voltage to 3.1V for charge storage on a capacitor (battery). A Self-Oscillating Boost Converter (SOBC) handles startup when the capacitor is initially discharged. A passive switching circuit was developed to enable source-free switching from the SOBC to the Main Boost Converter. The system yields 29% and 12% maximum power efficiency with -1dBm (794µW) and -5dBm (316µW) input power to the rectifier, respectively

System level power integrity transient analysis using a physics-based approach

With decreasing supply voltage level and massive demanding current on system chipset, power integrity design becomes more and more critical for system stability. The ultimate goal of well-designed power delivery network (PDN) is to deliver desired voltage level from the source to destination, in other words, to minimize voltage noise delivered to digital devices. The thesis is composed of three parts. The first part focuses on-die level power models including simplified chip power model (CPM) for system level analysis and the worst scenario current profile. The second part of this work introduces the physics-based equivalent circuit model to simplify the passive PDN model to RLC circuit netlist, to be compatible with any spice simulators and tremendously boost simulation speed. Then a novel system/chip level end-to-end transient model is proposed, including the die model and passive PDN model discussed in previous two chapters as well as a SIMPLIS based small signal VRM model. In the last part of the thesis, how to model voltage regulator module (VRM) is explicitly discussed. Different linear approximated VRM modeling approaches have been compared with the SIMPLIS small signal VRM model in both frequency domain and time domain. The comparison provides PI engineers a guideline to choose specific VRM model under specific circumstances. Finally yet importantly, a PDN optimization example was given. Other than previous PDN optimization approaches, a novel hybrid target impedance concept was proposed in this thesis, in order to improve system level PDN optimization process --Abstract, page iv

Space programs summary no. 37-65, volume 1 for the period 1 July - 31 August 1970. Flight projects

Mariner Mars 1971 projec

Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver

The mariner 9 power subsystem design and flight performance

The design and flight performance of the Mariner Mars 1971 power subsystem are presented. Mariner 9 was the first spacecraft to orbit another planet, and some of the power management techniques employed to support an orbital mission far from earth with marginal sunlight for its photovoltaic-battery power source are described. The performance of its nickel-cadmium battery during repetitive sun occultation phases of the mission, and the results of unique tests in flight to assess the performance capability of its solar array are reported

Review of world experience and properties of materials for encapsulation of terrestrial photovoltaic arrays

Published and unpublished information relating to encapsulation systems and materials properties was collected by searching the literature and appropriate data bases (over 1,300 documents were selected and reviewed) and by personal contacts including site and company visits. A data tabulation summarizing world experience with terrestrial photovoltaic arrays (50 installations) is presented in the report. Based on criteria of properties, processability, availability, and cost, candidate materials were identified which have potential for use in encapsulation systems for arrays with a lifetime of over 20 years high reliability, an efficiency greater than 10 percent, a total price less than $500/kW, and a production capacity of 500,000 kW/yr. The recommended materials (all commercially available) include, depending upon the device design, various borosilicate and soda-lime glasses and numerous polymerics suitable for specific encapsulation system functions

Family language policy of trilingual families in Japan: how parents try to raise multilingual children in a monolingual society

With increasing interest in early multilingual acquisition in the recent decades, Family Language Policy (FLP) has emerged as a fast-growing field of study exploring parents’ and children’s language-related ideologies, practices, and management within the family unit (Spolsky, 2004). However, a substantial part of the current body of FLP and early multilingual acquisition research is based on a) bilingual families b) living in Europe or Northern America c) with school-aged children and above. This study expands on current literature by investigating the parents’ role in early multilingual acquisition in trilingual families in Japan with young children between one and four years of age. After completing online questionnaires on their families’ demographic and language backgrounds, n=5 parents (n=4 mothers; n=1 father) participated in semi-structured online interviews to share their views on early multilingualism; their goals and expectations for their own children’s language development; their strategies and use of resources; and the challenges they have experienced in trying to pass on multiple languages to their children. The qualitative analysis through inductive coding revealed that individual backgrounds and experiences seem to shape their FLPs. Most parents seemed determined to provide their children with a multilingual upbringing and were highly emotionally invested in their children’s success. The parents worries and regrets for not supporting their children in the best way seemed to have been exacerbated by the limited access to FLP resources and support in the predominantly monolingual context of Japan

A model-based methodology for the evaluation of computerized group decision making

Increased global competition is forcing organizations to increase their use of group decision making today. Computerized group decision support aids (CGDSAs) are being developed to improve the efficiency of these groups and to improve decision quality. Even though the use of CGDSAs has increased, very little research has been done on the evaluation of CGDSAs. The purpose of this research was to develop a model-based generalized methodology for CGDSA evaluation from the user's perspective. Two models were developed as a foundation for the CGDSA evaluation methodology. The first model was a model of group decision making and the second model was a model of computer-aided group decision making. The group decision making model was based upon a basic input-output model with the problem as the input and the selected alternative as the output. Analogous to how problems are viewed in terms of classical design of experiments, independent variables affect the outcome (problem solution the dependent variable) of the decision making process. As in design of experiments, independent variables are either noise variables or control variables. In the model presented, the independent variables are further divided into four categories (internal, external, process, and problem) in the group decision making model as a way to help develop an exhaustive list of independent variables affecting the decision making process. The generalized methodology for CGDSA evaluation mapped directly to the computer-aided group decision making model. Solution quality is measured directly or by measuring independent variables that have been previously been correlated to solution quality using standard design of experiment techniques. The generalized methodology for CGDSA evaluation was applied to the assessment of ConsensusBuilder, an example of a CGDSA. As prescribed by the CGDSA evaluation methodology, usability was also assessed and practical use considerations were followed when designing the evaluation. The value of the ConsensusBuilder evaluation for this research was that it was possible to perform a thorough evaluation of ConsensusBuilder, a CGDSA, using the CGDSA Evaluation Methodology developed in this research. In addition to the ConsensusBuilder evaluation, six different CGDSA evaluations cited in the literature were assessed in terms of the CGDSA evaluation methodology

The Conference on High Temperature Electronics

The status of and directions for high temperature electronics research and development were evaluated. Major objectives were to (1) identify common user needs; (2) put into perspective the directions for future work; and (3) address the problem of bringing to practical fruition the results of these efforts. More than half of the presentations dealt with materials and devices, rather than circuits and systems. Conference session titles and an example of a paper presented in each session are (1) User requirements: High temperature electronics applications in space explorations; (2) Devices: Passive components for high temperature operation; (3) Circuits and systems: Process characteristics and design methods for a 300 degree QUAD or AMP; and (4) Packaging: Presently available energy supply for high temperature environment