## Geometrical Theory of Diffraction Formulation for On-Body Propagation

Research output: Contribution to journal › Journal article – Annual report year: 2019 › Research › peer-review

### Standard

**Geometrical Theory of Diffraction Formulation for On-Body Propagation.** / Kammersgaard, Nikolaj Peter Brunvoll; Kvist, Søren H.; Thaysen, Jesper; Jakobsen, Kaj Bjarne.

Research output: Contribution to journal › Journal article – Annual report year: 2019 › Research › peer-review

### Harvard

*IEEE Transactions on Antennas and Propagation*, vol. 67, no. 2, pp. 1143-1152. https://doi.org/10.1109/TAP.2018.2882596

### APA

*IEEE Transactions on Antennas and Propagation*,

*67*(2), 1143-1152. https://doi.org/10.1109/TAP.2018.2882596

### CBE

### MLA

*IEEE Transactions on Antennas and Propagation*. 2019, 67(2). 1143-1152. https://doi.org/10.1109/TAP.2018.2882596

### Vancouver

### Author

### Bibtex

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### RIS

TY - JOUR

T1 - Geometrical Theory of Diffraction Formulation for On-Body Propagation

AU - Kammersgaard, Nikolaj Peter Brunvoll

AU - Kvist, Søren H.

AU - Thaysen, Jesper

AU - Jakobsen, Kaj Bjarne

PY - 2019

Y1 - 2019

N2 - A Geometrical Theory of Diffraction model for onbody propagation is developed in the article. The exact solution to the canonical problem of a plane wave incident on an infinitely long cylinder, with arbitrary constitutive parameters, is found. The same is done for a magnetic and an electric infinitesimal dipole source of any orientation, located on the surface of the cylinder. The exact solutions are transformed with the Watson transformation to yield asymptotic expressions that are valid in the deep shadow region. These asymptotic expressions are validated by comparison to the numerically evaluated exact solution. It is found that the expressions are valid as long as the object is opaque, with a geometry down to the size of κ/κ2+τ2 > λ0/2, and the rays not too torsional τ/κ < 2, where κ and τ are the curvature and torsion of the local geometry, respectively. The asymptotic expressions are found to approximate the exact solution significantly better than the asymptotic expression of an equivalent perfect electric conductor geometry. The same is the case for the impedance boundary condition asymptotic approximation for low dielectric constant materials. Finally, the asymptotic expressions are generalized so they can be applied to any convex geometry of the human body or an opaque lossy dielectric of electrically large size.

AB - A Geometrical Theory of Diffraction model for onbody propagation is developed in the article. The exact solution to the canonical problem of a plane wave incident on an infinitely long cylinder, with arbitrary constitutive parameters, is found. The same is done for a magnetic and an electric infinitesimal dipole source of any orientation, located on the surface of the cylinder. The exact solutions are transformed with the Watson transformation to yield asymptotic expressions that are valid in the deep shadow region. These asymptotic expressions are validated by comparison to the numerically evaluated exact solution. It is found that the expressions are valid as long as the object is opaque, with a geometry down to the size of κ/κ2+τ2 > λ0/2, and the rays not too torsional τ/κ < 2, where κ and τ are the curvature and torsion of the local geometry, respectively. The asymptotic expressions are found to approximate the exact solution significantly better than the asymptotic expression of an equivalent perfect electric conductor geometry. The same is the case for the impedance boundary condition asymptotic approximation for low dielectric constant materials. Finally, the asymptotic expressions are generalized so they can be applied to any convex geometry of the human body or an opaque lossy dielectric of electrically large size.

KW - Asymptotic approximation

KW - Geometrical theory of diffraction (GTD)

KW - Lossy dielectric cylinder

KW - On-body communication

KW - Wireless body area network (WBAN)

U2 - 10.1109/TAP.2018.2882596

DO - 10.1109/TAP.2018.2882596

M3 - Journal article

VL - 67

SP - 1143

EP - 1152

JO - I E E E Transactions on Antennas and Propagation

JF - I E E E Transactions on Antennas and Propagation

SN - 0018-926X

IS - 2

ER -