Single Layered Periodic Structure Loaded Textile Patch Antennas

This thesis provides an investigation of a Single Layered Periodic Structure Loaded Textile Patch Antenna with probe feed excitation. Specifically, this thesis is concentrated on the application of wearable antenna arrays with space suit, since this thesis has collaboration with the University of North Dakota (UND) Space Suit Laboratory in the Space Studies Department. Topics include; platform interaction and placement of the antenna system. The goal is to increase antenna gain by loading the antenna with periodic cells. First, an introduction to items contained within this thesis will be given. The second chapter introduces microstrip patch antennas, their basic characteristics, and their feeding excitation methods. Continuing with microstip patch antennas, and how they are viewed with their fringing field effects. Then the theoretical designs of the physical dimensions of a patch antenna relative to its electrical length are included. This part then ends with a basic introduction to periodic structures, namely Electromagnetic Band Gap (EBG) structures. The third chapter covers wearable antennas, with and without periodic structures, and their applications. A review of surface waves and wave modes is given. This review produces a picture of how this once un-utilized energy (i.e. surface waves) can be recycled and reused to benefit positively increased gain. This can be accomplished by use of periodic structures loaded with the antenna. The fourth chapter covers the material, manufacturing, assembling, and measuring processes of textile antennas. This range of processes is journeyed as a joint collaboration between UNDs Electrical Engineering Department\u27s Applied Electromagnetics Laboratory, and the Technology Department\u27s Machine Shop. Lastly, simulation and design of a periodic loaded patch antenna are analyzed. This begins by first designing and simulating a free standing periodic cell coined C-mirror . The simulation results for reflection and dispersion characteristics are given. A 1 GHz antenna with specifications of textile material was designed. Once this antenna was realized, it was then loaded uni-planar with periodic cells with no vias. Experiments included varying the orientation, number of rows, and the placement of the cells with respect to the antenna. It was found that the Up-Down (UD) orientation with 2 rows and λo/12 placement demonstrated the greatest increase in gain. Furthermore, surface currents were seen to interact with the periodic cells. It could be seen that the arrangement of the cells adapted a network internally with the current flowing through the cells obtaining an inductive behavior and the capacitive behavior occurred between the cells stubs as well as between the cells defined by the Periodic Boundary Conditions (PBC). This surface current behavior, with the orientation of the periodic array with no vias became known as a Uni-Planar Parasitic Loaded Patch Antenna

Space Solar Power Satellite Systems, Modern Small Satellites, And Space Rectenna

Space solar power satellite (SSPS) systems is the concept of placing large satellite into geostationary Earth orbit (GEO) to harvest and convert massive amounts of solar energy into microwave energy, and to transmit the microwaves to a rectifying antenna (rectenna) array on Earth. The rectenna array captures and converts the microwave power into usable power that is injected into the terrestrial electric grid for use. This work approached the microwave power beam as an additional source of power (with solar) for lower orbiting satellites. Assuming the concept of retrodirectivity, a GEO-SSPS antenna array system tracks and delivers microwave power to lower orbiting satellites. The lower orbiting satellites are equipped with a stacked photovoltaic (PV)/rectenna array hybrid power generation unit (HPGU) in order to harvest solar and/or microwave energy for on-board use during orbit. The area, and mass of the PV array part of the HPGU was reduced at about 32% beginning-of-life power in order to achieve the spacecraft power requirements. The HPGU proved to offer a mass decrease in the PGU, and an increase in mission life due to longer living component life of the rectenna array. Moreover, greater mission flexibility is achieved through a track and power delivery concept. To validate the potential advantages offered by a HPGU, a mission concept was presented that utilizes modern small satellites as technology demonstrators. During launch, a smaller power receiving “daughter” satellite sits inside a larger power transmitting “mother” satellite. Once separated from the launch vehicle the daughter satellite is ejected away from the mother satellite, and each satellite deploys its respective power transmitting or power receiving hardware’s for experimentation. The concept of close proximity mission operations between the satellites is considered. To validate the technology of the space rectenna array part of the HPGU, six milestones were completed in the design. The first milestone considers thermal analysis for antennas, and the second milestone compares commercial off-the-shelve high frequency substrates for thermal, and outgassing characteristics. Since the design of the rectenna system is centralized around the diode component, a diode analysis was conducted for the third milestone. Next, to efficiently transfer power between the different parts of the rectenna system a coplanar stripline was consider for the fourth milestone. The fifth milestone is a balanced-to-unbalanced transition structure that is needed to properly feed and measure different systems of the rectenna. The last milestone proposes laboratory measurement setups. Each of these milestones is a separate research question that is answered in this dissertation. The results of these rectenna milestones can be integrated into a HPGU

Selecting a Center Pivot

This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Space Solar Rectifying Antenna On Earth

The realization of solar power from space is becoming increasingly closer as a solution to solving the continued growth in energy demand. Space based solar power is also being perceived as an alternative solution for non-renewable energy resources. Future solar power satellites will be positioned in orbit around the Earth where they will collect solar radiation. That radiation will be transformed into a microwave energy beam that is targeted to a receiving rectifying antenna or “rectenna” located on Earth’s surface. The received microwave energy will be converted into direct current electricity. This presentation focuses on the microwave patch antennas used with integrated rectifiers in ground receivers on Earth. Inset feed and quarter-wave microwave patch antennas and a microwave rectifier were engineered, manufactured, and tested in-house at the University of North Dakota. The results showed a resonant frequency close to the desired 2.45 GHz, but the rectifier demonstrated 21% power conversion efficiency from AC to DC at 15dBm. The antenna and rectifier were combined and analysis was performed for the parameters of distance of the receiving rectenna from the transmitter and power output upon rectification. The innovation of this project is the “Multi-Combinational Renewable Energy Efficient Generator ” that allows such energy attachments as terrestrial solar and wind, geo-thermal facilities, energy storage systems, and the rectenna itself to be integrated into the base structure. The future Global Electrical Grid will use solar power satellites as a space electrical node and, it is hoped, the MCREEG generator will serve as a ground electrical node. Advisors: Dr. Sima Noghanian, Dr. Hossein Salehfar, Dr. Isaac Chang, Dr. James Casler, Dr. Ron Fevi