andy marvin | University of York (original) (raw)

Papers by andy marvin

Research paper thumbnail of Average absorption cross-section of the human body measured at 1-12 GHz in a reverberant chamber: results of a human volunteer study

Physics in medicine and biology, Jan 7, 2014

The electromagnetic absorption cross-section (ACS) averaged over polarization and angle-of-incide... 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...

Research paper thumbnail of Changes in a printed circuit board's absorption cross section due to proximity to walls in a reverberant environment

2016 IEEE International Symposium on Electromagnetic Compatibility (EMC), 2016

Knowledge of the absorption cross section (ACS) of a printed circuit board (PCB) is essential whe... more Knowledge of the absorption cross section (ACS) of a printed circuit board (PCB) is essential when defining an enclosure's shielding effectiveness as it will determine how a PCB affects the internal electromagnetic (EM) field inside the enclosure. In this paper we show how the ACS changes when a PCB is in the vicinity of the enclosure walls by making measurements in a small reverberation chamber. We find that when the PCB is perpendicular to the chamber wall different measurement positions have little effect on the ACS, even when the PCB is positioned close to the wall. However, placing the PCB parallel to the chamber wall did show some differences in ACS. This information could be useful when considering situations where PCBS are stacked together or close to enclosure walls when in a reverberant environment.

Research paper thumbnail of A wide-band hybrid antenna for use in reverberation chambers

2013 IEEE International Symposium on Electromagnetic Compatibility, 2013

This paper describes the design and performance of a wide-band hybrid antenna suitable for use in... more This paper describes the design and performance of a wide-band hybrid antenna suitable for use in reverberation chambers. The antenna is characterised over the frequency range 100 MHz to 25 GHz showing that it performs well above 200 MHz although its ultimate highest operating frequency has not been established.

Research paper thumbnail of Using integral equation methods to incorporate open area test site effects in finite modelling techniques

9th International Conference on Electromagnetic Compatibility, 1994

ABSTRACT

Research paper thumbnail of Effect of power state on absorption cross section of personal computer components: Applications to enclosure shielding

2017 International Symposium on Electromagnetic Compatibility - EMC EUROPE, 2017

Knowledge of the shielding effectiveness of an enclosure is important for the electromagnetic com... more Knowledge of the shielding effectiveness of an enclosure is important for the electromagnetic compatibility of electronic systems. The shielding effectiveness of an enclosure depends on the absorption cross section of its contents. It might be expected that the energy absorption in an electronic circuit changes according to the operating state of the semiconductor devices which compose the active components. In most published research, the absorption cross section measurements were performed when the contents were unpowered. In this paper we compare the measured absorption cross sections of the components of a personal computer in powered and unpowered states. Comparisons indicate that power and the particular operating configuration do not have a significant influence on the absorption cross section. This means that the process of determining absorption cross sections of circuit boards and other components can be easily achieved without the need to provide power and define a particular operating state.

Research paper thumbnail of Thermal Noise Measurements in a Reverberation Chamber

IEEE Transactions on Electromagnetic Compatibility, 2022

Two models describing properties of the thermal noise power emerging from an antenna mounted in a... more Two models describing properties of the thermal noise power emerging from an antenna mounted in a reverberation chamber are described. The first compares the reverberation chamber to an over-moded cavity acting as a blackbody source; the second describes the noise in terms of the antenna noise temperature. Measurements based on the antenna noise temperature model show the noise power to be dependent on the position of the rotating mechanical stirrer. The correlation of the antenna noise temperature with the stirrer position dependent antenna mis-match factor is shown. When a signal is injected into the chamber measurements of the signal to noise power ratio show that this ratio is dependent on the stirrer position and also the position of the signal source within the chamber. These results have significant consequences for the detection of weak signals from radiating sources in a reverberation chamber. Index Terms-reverberation chamber, antenna noise temperature, signal-to-noise ratio.

Research paper thumbnail of A 1.3 GHz, High Voltage Mesoband Dipole Antenna for IEMI Testing

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

A resonant dipole antenna for testing immunity of equipment to intentional electromagnetic interf... more A resonant dipole antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI) is described, along with simulated and measured test results which are in good agreement and demonstrate the high voltage operation.

Research paper thumbnail of Proposed Methods to Measure the Shielding Performance of PCB Level Enclosures

IEICE Proceeding Series

KULeuven. ...

Research paper thumbnail of Enclosure shielding assessment using surrogate contents fabricated from radio absorbing material

2016 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC), 2016

The electromagnetic environment inside an equipment enclosure at high frequencies is strongly dep... more The electromagnetic environment inside an equipment enclosure at high frequencies is strongly dependent on the absorption of energy by the contents. This effect is neglected by current shielding measurement standards. Here we extended the concept of shielding measurements using surrogate "representative contents" proposed at lower frequencies into the regime were the enclosure is electrically large. We demonstrate how a surrogate fabricated from radio absorbing material can be made to give the same overall absorption as a real printed circuit board and hence produce the same internal environment inside an enclosure during a shielding measurement.

Research paper thumbnail of A method of reducing the number of ferrite tiles in an absorber lined chamber

EMC York 99. International Conference and Exhibition on Electromagnetic Compatibility, 1999

ABSTRACT Anechoic chambers are used for both emission and immunity testing but the ferrite tiles ... 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

Research paper thumbnail of Determining the Electromagnetic Shielding Properties of Non-Woven Materials

The issues of measuring, and predicting, the anisotropic electromagnetic shielding properties of ... 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.

Research paper thumbnail of Efficient simulations for automotive design

Some preliminary results are presented for the statistical coupling of EM radiation to a transmis... 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.

Research paper thumbnail of BOARD OF DIRECTORS Executive Officers

Research paper thumbnail of A 150 MHz, High Voltage Mesoband Dipole Antenna for IEMI Testing

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

An antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI) i... more An antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI) is described, along with simulated and measured test results which show a good agreement and demonstrate the high-voltage operation.

Research paper thumbnail of A Lightweight, Compact, High voltage Hyperband Antenna for IEMI Testing

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

A robust lightweight antenna for testing immunity of equipment to intentional electromagnetic int... more A robust lightweight antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI), based on a planar Vivaldi design, is described, along with simulated and measured test results.

Research paper thumbnail of Analysis and Estimation of Electromagnetic Energy Coupled into IC packages

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

Interference analysis and prediction in integrated circuits (ICs) is of significant interest to t... more Interference analysis and prediction in integrated circuits (ICs) is of significant interest to the Electromagnetic Compatibility (EMC) community. In this paper, an easy method is introduced to estimate the level of RF interference coupled into ICs through the package. Although IC packages are in different forms with large number of pins, the presented analysis method provides a general solution and greatly shortens the computation time by creating a simplified model with consideration of the cross coupling between pins. The expected voltage range at the outer ends and inner ends of the pins are also investigated for resistive loads. The levels of energy coupled into PCB traces and packages are also compared for immunity analysis.

Research paper thumbnail of Experience of correlating measurements in the frequency range 1 MHz to 30 MHz

IEE Colloquium on `The Correlation Between Measurements in Screened Rooms and in Open Area Test Sites', 1996

... The operation of the antenna in a screened enclosure is not under plane wave conditions and s... 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. ...

Research paper thumbnail of Experience of using a spherical dipole as a transfer standard for radiated emissions measurements below 30 MHz

IEE Seminar on Measurement Dissemination by Transfer Methods, 1999

... It should be noted that the results are not those that would be obtained for free space wave ... 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. ...

Research paper thumbnail of Considerations leading to a strategy for the prediction of radiated emissions

Research paper thumbnail of New developments in the calibration of screened enclosure-antenna combinations for radiated emission measurements in the 1 MHz to 30 MHz frequency range

... by the elemental electric dipole placed on the test site are measured by the monopole (stored... 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. ...

Research paper thumbnail of Average absorption cross-section of the human body measured at 1-12 GHz in a reverberant chamber: results of a human volunteer study

Physics in medicine and biology, Jan 7, 2014

The electromagnetic absorption cross-section (ACS) averaged over polarization and angle-of-incide... 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...

Research paper thumbnail of Changes in a printed circuit board's absorption cross section due to proximity to walls in a reverberant environment

2016 IEEE International Symposium on Electromagnetic Compatibility (EMC), 2016

Knowledge of the absorption cross section (ACS) of a printed circuit board (PCB) is essential whe... more Knowledge of the absorption cross section (ACS) of a printed circuit board (PCB) is essential when defining an enclosure's shielding effectiveness as it will determine how a PCB affects the internal electromagnetic (EM) field inside the enclosure. In this paper we show how the ACS changes when a PCB is in the vicinity of the enclosure walls by making measurements in a small reverberation chamber. We find that when the PCB is perpendicular to the chamber wall different measurement positions have little effect on the ACS, even when the PCB is positioned close to the wall. However, placing the PCB parallel to the chamber wall did show some differences in ACS. This information could be useful when considering situations where PCBS are stacked together or close to enclosure walls when in a reverberant environment.

Research paper thumbnail of A wide-band hybrid antenna for use in reverberation chambers

2013 IEEE International Symposium on Electromagnetic Compatibility, 2013

This paper describes the design and performance of a wide-band hybrid antenna suitable for use in... more This paper describes the design and performance of a wide-band hybrid antenna suitable for use in reverberation chambers. The antenna is characterised over the frequency range 100 MHz to 25 GHz showing that it performs well above 200 MHz although its ultimate highest operating frequency has not been established.

Research paper thumbnail of Using integral equation methods to incorporate open area test site effects in finite modelling techniques

9th International Conference on Electromagnetic Compatibility, 1994

ABSTRACT

Research paper thumbnail of Effect of power state on absorption cross section of personal computer components: Applications to enclosure shielding

2017 International Symposium on Electromagnetic Compatibility - EMC EUROPE, 2017

Knowledge of the shielding effectiveness of an enclosure is important for the electromagnetic com... more Knowledge of the shielding effectiveness of an enclosure is important for the electromagnetic compatibility of electronic systems. The shielding effectiveness of an enclosure depends on the absorption cross section of its contents. It might be expected that the energy absorption in an electronic circuit changes according to the operating state of the semiconductor devices which compose the active components. In most published research, the absorption cross section measurements were performed when the contents were unpowered. In this paper we compare the measured absorption cross sections of the components of a personal computer in powered and unpowered states. Comparisons indicate that power and the particular operating configuration do not have a significant influence on the absorption cross section. This means that the process of determining absorption cross sections of circuit boards and other components can be easily achieved without the need to provide power and define a particular operating state.

Research paper thumbnail of Thermal Noise Measurements in a Reverberation Chamber

IEEE Transactions on Electromagnetic Compatibility, 2022

Two models describing properties of the thermal noise power emerging from an antenna mounted in a... more Two models describing properties of the thermal noise power emerging from an antenna mounted in a reverberation chamber are described. The first compares the reverberation chamber to an over-moded cavity acting as a blackbody source; the second describes the noise in terms of the antenna noise temperature. Measurements based on the antenna noise temperature model show the noise power to be dependent on the position of the rotating mechanical stirrer. The correlation of the antenna noise temperature with the stirrer position dependent antenna mis-match factor is shown. When a signal is injected into the chamber measurements of the signal to noise power ratio show that this ratio is dependent on the stirrer position and also the position of the signal source within the chamber. These results have significant consequences for the detection of weak signals from radiating sources in a reverberation chamber. Index Terms-reverberation chamber, antenna noise temperature, signal-to-noise ratio.

Research paper thumbnail of A 1.3 GHz, High Voltage Mesoband Dipole Antenna for IEMI Testing

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

A resonant dipole antenna for testing immunity of equipment to intentional electromagnetic interf... more A resonant dipole antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI) is described, along with simulated and measured test results which are in good agreement and demonstrate the high voltage operation.

Research paper thumbnail of Proposed Methods to Measure the Shielding Performance of PCB Level Enclosures

IEICE Proceeding Series

KULeuven. ...

Research paper thumbnail of Enclosure shielding assessment using surrogate contents fabricated from radio absorbing material

2016 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC), 2016

The electromagnetic environment inside an equipment enclosure at high frequencies is strongly dep... more The electromagnetic environment inside an equipment enclosure at high frequencies is strongly dependent on the absorption of energy by the contents. This effect is neglected by current shielding measurement standards. Here we extended the concept of shielding measurements using surrogate "representative contents" proposed at lower frequencies into the regime were the enclosure is electrically large. We demonstrate how a surrogate fabricated from radio absorbing material can be made to give the same overall absorption as a real printed circuit board and hence produce the same internal environment inside an enclosure during a shielding measurement.

Research paper thumbnail of A method of reducing the number of ferrite tiles in an absorber lined chamber

EMC York 99. International Conference and Exhibition on Electromagnetic Compatibility, 1999

ABSTRACT Anechoic chambers are used for both emission and immunity testing but the ferrite tiles ... 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

Research paper thumbnail of Determining the Electromagnetic Shielding Properties of Non-Woven Materials

The issues of measuring, and predicting, the anisotropic electromagnetic shielding properties of ... 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.

Research paper thumbnail of Efficient simulations for automotive design

Some preliminary results are presented for the statistical coupling of EM radiation to a transmis... 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.

Research paper thumbnail of BOARD OF DIRECTORS Executive Officers

Research paper thumbnail of A 150 MHz, High Voltage Mesoband Dipole Antenna for IEMI Testing

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

An antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI) i... more An antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI) is described, along with simulated and measured test results which show a good agreement and demonstrate the high-voltage operation.

Research paper thumbnail of A Lightweight, Compact, High voltage Hyperband Antenna for IEMI Testing

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

A robust lightweight antenna for testing immunity of equipment to intentional electromagnetic int... more A robust lightweight antenna for testing immunity of equipment to intentional electromagnetic interference (IEMI), based on a planar Vivaldi design, is described, along with simulated and measured test results.

Research paper thumbnail of Analysis and Estimation of Electromagnetic Energy Coupled into IC packages

2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium, 2021

Interference analysis and prediction in integrated circuits (ICs) is of significant interest to t... more Interference analysis and prediction in integrated circuits (ICs) is of significant interest to the Electromagnetic Compatibility (EMC) community. In this paper, an easy method is introduced to estimate the level of RF interference coupled into ICs through the package. Although IC packages are in different forms with large number of pins, the presented analysis method provides a general solution and greatly shortens the computation time by creating a simplified model with consideration of the cross coupling between pins. The expected voltage range at the outer ends and inner ends of the pins are also investigated for resistive loads. The levels of energy coupled into PCB traces and packages are also compared for immunity analysis.

Research paper thumbnail of Experience of correlating measurements in the frequency range 1 MHz to 30 MHz

IEE Colloquium on `The Correlation Between Measurements in Screened Rooms and in Open Area Test Sites', 1996

... The operation of the antenna in a screened enclosure is not under plane wave conditions and s... 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. ...

Research paper thumbnail of Experience of using a spherical dipole as a transfer standard for radiated emissions measurements below 30 MHz

IEE Seminar on Measurement Dissemination by Transfer Methods, 1999

... It should be noted that the results are not those that would be obtained for free space wave ... 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. ...

Research paper thumbnail of Considerations leading to a strategy for the prediction of radiated emissions

Research paper thumbnail of New developments in the calibration of screened enclosure-antenna combinations for radiated emission measurements in the 1 MHz to 30 MHz frequency range

... by the elemental electric dipole placed on the test site are measured by the monopole (stored... 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. ...