Monograph on Computation of RF Hazards

No abstract availabl

Measuring Dielectrics Using Shielded Loop Antennas

abstract: This work is concerned with the use of shielded loop antennas to measure permittivity as a low-cost alternative to expensive probe-based systems for biological tissues and surrogates. Beginning with the development of a model for simulation, the shielded loop was characterized. Following the simulations, the shielded loop was tested in free space and while holding a cup of water. The results were then compared. Because the physical measurements and the simulation results did not line up, simulation results were forgone. The shielded loop antenna was then used to measure a set of NaCl saline solutions with varying molarities. This measurement was used as a calibration set, and the results were analyzed. By taking the peak magnitude of the input impedance of each solution, a trend was created for the molarities. Following this measurement and analysis, a set of unknown solutions was tested. Based on the measurements and the empirical trends from the calibration set of measurements, the molarities of the valid unknown solutions were estimated. It is shown that using the known molarities, permittivity can also be calculated. Using the estimated molarities of the unknown solutions, the permittivity of each solution was calculated. The maximum error for the estimation was 1.07% from the actual data.Dissertation/ThesisMasters Thesis Electrical Engineering 201

Electromagnetic Compatibility Considerations for International Space Station Payload Developers

The International Space Station (ISS) is a laboratory for scientific research, innovative technology development, and global education. The ISS provides a number of facilities and platforms for payload developers and investigators to conduct biological, microgravity, and Earth and space observation science, as well as for performing technology development. Due to the unique nature of the ISS vehicle and its electrical power and data systems, achieving electromagnetic compatibility (EMC) with the vehicle requires special considerations by the payload developer. The ISS electromagnetic interference (EMI) requirements and test methods are based on MIL-STD-461, Electromagnetic Emissions and Susceptibility Requirements for the Control of Electromagnetic Interference, Revision C, and MIL-STD-462, Electromagnetic Interference Characteristics, Measurement of, respectively. The low source impedance of the test setup requires special considerations when designing or selecting EMI power filters and switched mode power supplies. Many filters, suited for later revisions of MIL-STD-461, will result in non-compliant designs. ISS electrical power system power quality requirements, imposed to protect the stability of the system, can also affect EMI filter design. The selection and use of commercial-off-the-shelf (COTS) equipment for ISS applications requires special considerations to meet both EMC and crew safety requirements. Furthermore, the ISS environment can provide unique immunity challenges; if the payload developer ignores these challenges, the result is a possible loss of science or impact to technology demonstration. The ISS provides a unique opportunity for the science and technology development community. However, in order to be successful, the payload developer must incorporate special EMC considerations, many of which will be presented

Design and implementation of near-field measurement probes

The problems of electronics product because of electromagnetic incompatibility are in-creasing constantly. To end this incompatibility the European Union (EU) has decided to empower the Directive 2004/108/EC so devices could operate close to each other properly. The product manufacturers are required to make standardized tests to verify that the product is compliant with the Directive 2004/108/EC. Many times the designer uses a lot of time to design product functions and uses project time for verification of these functions. However, the final product should be tested in according the most recent electromagnetic standards and one of these many tests is the radio disturbance test as a function of frequency and for this disturbance the standard states limit values. This thesis is intended to bring out some phenomena by using calculations to show that how these limit values are easily broken if the product contains some design faults for example in the printed circuit board. The main focus is to design a near-field measure-ment probes which are electric field probes, magnetic field probes and a high-frequency current probe. The standardized test is done in the far field, and sometimes for the designer it is very difficult to spot the origin of interference. According the measurement results of this thesis the designed and implemented near-field probes can be used efficiently to locate the origin of interference. The magnetic field probe and electric field probe can be used to spot interference source from the printed circuit board (PCB) and high-frequency cur-rent probe can be used to search product external cable which carries common-mode current. According the calculations of this thesis the common-mode current is most problematic radiator from electronic product cabling.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Wireless Power Transfer

abstract: A new loop configuration capable of reducing power radiation magnitudes lower than conventional loops has been developed. This configuration is demonstrated for the case of two coaxial loops of 0.1 meter radius coupled via the magnetic reactive field. Utilizing electromagnetism theory, techniques from antenna design and a new near field design initiative, the ability to design a magnetic field has been investigated by using a full wave simulation tool. The method for realization is initiated from first order physics model, ADS and onto a full wave situation tool for the case of a non-radiating helical loop. The exploration into the design of a magnetic near field while mitigating radiation power is demonstrated using an real number of twists to form a helical wire loop while biasing the integer twisted loop in a non-conventional moebius termination. The helix loop setup as a moebius loop convention can also be expressed as a shorted antenna scheme. The 0.1 meter radius helix antenna is biased with a 1MHz frequency that categorized the antenna loop as electrically small. It is then demonstrated that helical configuration reduces the electric field and mitigates power radiation into the far field. In order to compare the radiated power reduction performance of the helical loop a shielded loop is used as a baseline for comparison. The shielded loop system of the same geometric size and frequency is shown to have power radiation expressed as -46.1 dBm. The power radiated mitigation method of the helix loop reduces the power radiated from the two loop system down to -98.72 dBm.Dissertation/ThesisMasters Thesis Electrical Engineering 201

Dual And Triple Feeding For Full-Wave Dipole Antenna [TK7871.67.D56 H677 2007 f rb].

Tesis ini menfokus kepada pembangunan teknik baru untuk suapan antena dwikutub gelombang penuh. Terdapat tujuh cara suapan dalam kajian ini, empat cara untuk dua suapan dan tiga cara untuk tiga suapan. This thesis is focused on the development of a new full-wave dipole antenna feeding technique. Seven such techniques of feeding were tested in the study, in which, four were used with dual feeding and three with triple feeding

Communications techniques and equipment: A compilation

This Compilation is devoted to equipment and techniques in the field of communications. It contains three sections. One section is on telemetry, including articles on radar and antennas. The second section describes techniques and equipment for coding and handling data. The third and final section includes descriptions of amplifiers, receivers, and other communications subsystems

Investigations on electromagnetic noises and interactions in electronic architectures : a tutorial case on a mobile system

Electromagnetic interactions become critic in embedded and smart electronic structures. The increase of electronic performances confined in a finite volume or support for mobile applications defines new electromagnetic environment and compatibility configurations (EMC). With canonical demonstrators developed for tutorials and EMC experiences, this paper present basic principles and experimental techniques to investigate and control these severe interferences. Some issues are reviewed to present actual and future scientific challenges for EMC at electronic circuit level

Cable analysis for electromagnetic compatibility issues

This dissertation consists of three papers. In the first paper, a high-sensitivity resonant electric field probe was designed, consisting of an LC resonator loaded by quarter-wave transformers. At the resonant frequency of 1.577 GHz, the measured |S21| from a matched trace to the resonant probe was approximately 6.6 dB higher than that of an equivalently sized broadband probe. In the second paper, a method for creating a simple SPICE model is proposed such that the SPICE model allows prediction of radiated emissions in component level tests. The radiation from the ground connections between the cables and return plane dominates over the radiation from the horizontal cables. In the third paper, a methodology for measuring coupling parameters and modeling crosstalk within aircraft cable connectors at low frequencies (\u3c 400 MHz) was developed. The accuracy of the model was evaluated through comparison of simulated and measured results. Additionally, a closed-form solution was developed to estimate the worst-case envelope of the differential crosstalk --Abstract, page iv