andy marvin
University of York, Electronics, Faculty Member
The electromagnetic absorption cross-section (ACS) averaged over polarization and angle-of-incidence of 60 ungrounded adult subjects was measured at microwave frequencies of 1-12 GHz in a reverberation chamber. Average ACS is important in... more
The electromagnetic absorption cross-section (ACS) averaged over polarization and angle-of-incidence of 60 ungrounded adult subjects was measured at microwave frequencies of 1-12 GHz in a reverberation chamber. Average ACS is important in non-ionizing dosimetry and exposure studies, and is closely related to the whole-body averaged specific absorption rate (WBSAR). The average ACS was measured with a statistical uncertainty of less than 3% and high frequency resolution for individuals with a range of body shapes and sizes allowing the statistical distribution of WBSAR over a real population with individual internal and external morphologies to be determined. The average ACS of all subjects was found to vary from 0.15 to 0.4 m(2); for an individual subject it falls with frequency over 1-6 GHz, and then rises slowly over the 6-12 GHz range in which few other studies have been conducted. Average ACS and WBSAR are then used as a surrogate for worst-case ACS/WBSAR, in order to study thei...
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Research Interests: Physics and Reverberation
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KULeuven. ...
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ABSTRACT Anechoic chambers are used for both emission and immunity testing but the ferrite tiles used to line the inside of the chamber are extremely expensive. This paper describes a method of reducing the number of tiles, whilst... more
ABSTRACT Anechoic chambers are used for both emission and immunity testing but the ferrite tiles used to line the inside of the chamber are extremely expensive. This paper describes a method of reducing the number of tiles, whilst ensuring a reliable test environment. The quality of a chamber is assessed by the magnitude of the difference between the normalised site attenuation (NSA) inside the chamber, and the theoretical NSA of free space. The chamber being acceptable if this is less than 4 dB at all frequencies in the range of interest. A genetic algorithm is used to optimise the layout of tiles with only 80% of the chamber walls covered. Transmission line matrix (TLM) modelling is used to determine the NSA in the chamber. Measurements provided for comparison show that the optimised tile layout with 80% coverage gives results as good as a fully lined chamber
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The issues of measuring, and predicting, the anisotropic electromagnetic shielding properties of electrically conductive, non-woven materials are considered. An efficient method for measuring the shielding properties is along with a... more
The issues of measuring, and predicting, the anisotropic electromagnetic shielding properties of electrically conductive, non-woven materials are considered. An efficient method for measuring the shielding properties is along with a stochastic model which can predict the sheet conductance is described.
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Some preliminary results are presented for the statistical coupling of EM radiation to a transmission line inside a lossy chamber with an aperture. The rapid Intermediate Level Circuit Modelling (ILCM) technique has been used to obtain... more
Some preliminary results are presented for the statistical coupling of EM radiation to a transmission line inside a lossy chamber with an aperture. The rapid Intermediate Level Circuit Modelling (ILCM) technique has been used to obtain the results, which have relevance to the calculation of the probability of failure of a vehicle subsystem in situ.
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Research Interests: Business and Accounting
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... The operation of the antenna in a screened enclosure is not under plane wave conditions and so the validity of the antenna factor is suspect. ... electric dipole placed on the test site are measured by the monopole (stored in file... more
... The operation of the antenna in a screened enclosure is not under plane wave conditions and so the validity of the antenna factor is suspect. ... electric dipole placed on the test site are measured by the monopole (stored in file Osee) and loop (stored in file OSem) antennas. ...
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... It should be noted that the results are not those that would be obtained for free space wave impedance, indicating the different propagation mechanisms ... dipole placed on the test site are measured by the monopole (stored in file... more
... It should be noted that the results are not those that would be obtained for free space wave impedance, indicating the different propagation mechanisms ... dipole placed on the test site are measured by the monopole (stored in file Osee) and loop (stored in file OSem) antennas. ...
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... by the elemental electric dipole placed on the test site are measured by the monopole (stored in file Osee) and loop (stored in file OSem) antennas. ... dipole is placed on top of the EUT at the centre of its front face as shown in... more
... by the elemental electric dipole placed on the test site are measured by the monopole (stored in file Osee) and loop (stored in file OSem) antennas. ... dipole is placed on top of the EUT at the centre of its front face as shown in Fig 2 oriented to produce a vertically polarised wave. ...
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The ground plane plays a major role in a printed circuit board (PCB) EMC characteristics but usually its effect can not be evaluated until the final design stages when the circuit is finished and the EMC tests are carried out. In this... more
The ground plane plays a major role in a printed circuit board (PCB) EMC characteristics but usually its effect can not be evaluated until the final design stages when the circuit is finished and the EMC tests are carried out. In this paper a new method to evaluate the PCB ground plane goodness at earlier design stages is presented. The method uses an indirect measurement of the power dissipated by the PCB based on the resonance inside an enclosure. The radiated EMI from several PCB showing a good correlation with the resonance measurement are presented.
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ABSTRACT Not Available
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In this paper we present an exposure assessment for a low profile distributed antenna fitted within an archway for a walk-through counter surveillance application. A numerical electromagnetic model, based on the method-of-moments, is used... more
In this paper we present an exposure assessment for a low profile distributed antenna fitted within an archway for a walk-through counter surveillance application. A numerical electromagnetic model, based on the method-of-moments, is used to develop a simple distributed structure antenna with optimum return loss factor in the frequency band of interest. An exposure assessment is then made using the
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Emerging telecommunication systems, with new devices and new transmission techniques modify the exposure of the population to electromagnetic fields [UMTS Forum, October 2000] [UMTS Forum, January 2002]. Although the risk for human health... more
Emerging telecommunication systems, with new devices and new transmission techniques modify the exposure of the population to electromagnetic fields [UMTS Forum, October 2000] [UMTS Forum, January 2002]. Although the risk for human health is currently thought to be low, there is a need to clarify these changes. This work involves analyzing typical scenarios and worst cases and developing new techniques
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... the same construction and the same en-vironment. This problem has been discussed in [3]. GTEM cells are all constructed in the same way and are independent of the location. However, as long as the OATS is the standard en-vironment the... more
... the same construction and the same en-vironment. This problem has been discussed in [3]. GTEM cells are all constructed in the same way and are independent of the location. However, as long as the OATS is the standard en-vironment the GTEM cell measurements have to ...
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... Learn From The Experts: Neville Thiele Neville Thiele "On Alan Blumlein"; Oral History Project Gallery; Other AES Publications. ... Authors: Angus, James A.; Marvin, Andrew C.; Clegg, Janet... more
... Learn From The Experts: Neville Thiele Neville Thiele "On Alan Blumlein"; Oral History Project Gallery; Other AES Publications. ... Authors: Angus, James A.; Marvin, Andrew C.; Clegg, Janet Affiliation: Department of Electronics,University of York, York, England AES Convention:96 ...
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... Its purpose is to help them achieve good practice in EMC emission and immunity tests with theirGTEM cell. Reference is made to the IEC Standard 61000-4-20 on the EMC uses of GTEM cells. Page 3. ... repeated the emission measurements... more
... Its purpose is to help them achieve good practice in EMC emission and immunity tests with theirGTEM cell. Reference is made to the IEC Standard 61000-4-20 on the EMC uses of GTEM cells. Page 3. ... repeated the emission measurements in their GTEM cell. Page 4. ...
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This paper considers the use of a slot antenna in the calibration of a reverberation chamber. In using a slot antenna the need for a balun is reduced which simplifies antenna construction. The behaviour of a slot antenna is compared to a... more
This paper considers the use of a slot antenna in the calibration of a reverberation chamber. In using a slot antenna the need for a balun is reduced which simplifies antenna construction. The behaviour of a slot antenna is compared to a dipole antenna and it is found that the field uniformity results obtained with a slot are more pessimistic
Research Interests: EMC and Slot Antenna
PCB-level shielding enclosures differ from the other shielding products in several aspects due to their small volume and therefore pose new challenges to the evaluation of performance. This paper describes several possible approaches, and... more
PCB-level shielding enclosures differ from the other shielding products in several aspects due to their small volume and therefore pose new challenges to the evaluation of performance. This paper describes several possible approaches, and issues about using a reverberation chamber to accomplish a fast and reliable measurement. The interaction between the internal source and the enclosure is also investigated. In
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The magnitude of a component of the electric field ERec inside a single mechanical stirred chamber is known to follow Rayleigh distribution, however, for the field inside an enclosure nested in a larger chamber, the probability... more
The magnitude of a component of the electric field ERec inside a single mechanical stirred chamber is known to follow Rayleigh distribution, however, for the field inside an enclosure nested in a larger chamber, the probability distribution function (PDF) of the ERec is unclear. In this paper the hypothesis of the PDF of a frequency stirred ERec is provided and