Advanced

Sum rules and constraints on passive systems - a general approach and applications to electromagnetic scattering

Bernland, Anders LU (2010)
Abstract
Physical processes are often modeled as input-output systems. Many such systems obey passivity, which means that power is dissipated in the process.

This thesis deals with the inevitable constraints imposed on physical systems due to passivity. A general approach to derive sum rules and physical limitations on passive systems is presented.

The sum rules relate the dynamical behaviour of a system to its static and/or high-frequency properties. This is beneficial, since static properties are in general easier to determine.

The physical limitations indicate what can, and what can not, be expected from certain passive systems.

At the core of the general approach is a set of integral identities for... (More)
Physical processes are often modeled as input-output systems. Many such systems obey passivity, which means that power is dissipated in the process.

This thesis deals with the inevitable constraints imposed on physical systems due to passivity. A general approach to derive sum rules and physical limitations on passive systems is presented.

The sum rules relate the dynamical behaviour of a system to its static and/or high-frequency properties. This is beneficial, since static properties are in general easier to determine.

The physical limitations indicate what can, and what can not, be expected from certain passive systems.

At the core of the general approach is a set of integral identities for Herglotz functions, a function class intimately related to the transfer functions of passive systems.



In this thesis, the general approach is also applied to a specific problem: the scattering and absorption of electromagnetic vector spherical waves by

various objects.

Physical limitations are derived, which limit the absorption of power from each individual spherical wave. They are particularly useful for electrically small scatterers. The results can be used in many fields where an understanding of the interaction between electromagnetic

waves and matter is vital.

One interesting application is within antenna theory, where the limitations are helpful from a designer's viewpoint; they can give an understanding as to what factors limit performance, and also indicate if there is room for improvement or not. (Less)
Please use this url to cite or link to this publication:
author
supervisor
organization
publishing date
type
Thesis
publication status
published
subject
pages
100 pages
publisher
Department of Electrical and Information Technology, Lund University
project
EIT_HSWC:Antenna MIMO antennas and channels
language
English
LU publication?
yes
id
afee4a8f-af69-44b5-b62b-fda6bd4c5961 (old id 1607148)
date added to LUP
2010-05-21 12:17:22
date last changed
2018-05-29 10:02:26
@misc{afee4a8f-af69-44b5-b62b-fda6bd4c5961,
  abstract     = {Physical processes are often modeled as input-output systems. Many such systems obey passivity, which means that power is dissipated in the process. <br/><br>
This thesis deals with the inevitable constraints imposed on physical systems due to passivity. A general approach to derive sum rules and physical limitations on passive systems is presented. <br/><br>
The sum rules relate the dynamical behaviour of a system to its static and/or high-frequency properties. This is beneficial, since static properties are in general easier to determine. <br/><br>
The physical limitations indicate what can, and what can not, be expected from certain passive systems. <br/><br>
At the core of the general approach is a set of integral identities for Herglotz functions, a function class intimately related to the transfer functions of passive systems. <br/><br>
<br/><br>
In this thesis, the general approach is also applied to a specific problem: the scattering and absorption of electromagnetic vector spherical waves by<br/><br>
various objects. <br/><br>
Physical limitations are derived, which limit the absorption of power from each individual spherical wave. They are particularly useful for electrically small scatterers. The results can be used in many fields where an understanding of the interaction between electromagnetic<br/><br>
waves and matter is vital. <br/><br>
One interesting application is within antenna theory, where the limitations are helpful from a designer's viewpoint; they can give an understanding as to what factors limit performance, and also indicate if there is room for improvement or not.},
  author       = {Bernland, Anders},
  language     = {eng},
  note         = {Licentiate Thesis},
  pages        = {100},
  publisher    = {Department of Electrical and Information Technology, Lund University},
  title        = {Sum rules and constraints on passive systems - a general approach and applications to electromagnetic scattering},
  year         = {2010},
}