# Pathloss Calculation Using the Transmission Line Matrix and Finite Difference Time Domain Methods With Coarse Grids

## Abstract

Numerical simulations of the wave equation that are intended to provide accurate time domain solutions require a computational mesh with grid points separated by a distance less than the wavelength of the source term and initial data. However, calculations of radio signal pathloss generally do not require accurate time domain solutions. This paper describes an approach for calculating pathloss by using the finite difference time domain and transmission line matrix models of wave propagation on a grid with points separated by distances much greater than the signal wavelength. The calculated pathloss can be kept close to the true value for freespace propagation with an appropriate selection of initial conditions. This method can also simulate diffraction with an error governed by the ratio of the signal wavelength to the grid spacing.

- Authors:

- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

- Publication Date:

- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1349775

- Alternate Identifier(s):
- OSTI ID: 1349776; OSTI ID: 1408652

- Grant/Contract Number:
- AC05-00OR22725

- Resource Type:
- Journal Article: Published Article

- Journal Name:
- IEEE Transactions on Antennas and Propagation

- Additional Journal Information:
- Journal Volume: 65; Journal Issue: 4; Journal ID: ISSN 0018-926X

- Publisher:
- IEEE

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 97 MATHEMATICS AND COMPUTING

### Citation Formats

```
Nutaro, James, and Kuruganti, Teja.
```*Pathloss Calculation Using the Transmission Line Matrix and Finite Difference Time Domain Methods With Coarse Grids*. United States: N. p., 2017.
Web. doi:10.1109/TAP.2017.2657494.

```
Nutaro, James, & Kuruganti, Teja.
```*Pathloss Calculation Using the Transmission Line Matrix and Finite Difference Time Domain Methods With Coarse Grids*. United States. doi:10.1109/TAP.2017.2657494.

```
Nutaro, James, and Kuruganti, Teja. Fri .
"Pathloss Calculation Using the Transmission Line Matrix and Finite Difference Time Domain Methods With Coarse Grids". United States.
doi:10.1109/TAP.2017.2657494.
```

```
@article{osti_1349775,
```

title = {Pathloss Calculation Using the Transmission Line Matrix and Finite Difference Time Domain Methods With Coarse Grids},

author = {Nutaro, James and Kuruganti, Teja},

abstractNote = {Numerical simulations of the wave equation that are intended to provide accurate time domain solutions require a computational mesh with grid points separated by a distance less than the wavelength of the source term and initial data. However, calculations of radio signal pathloss generally do not require accurate time domain solutions. This paper describes an approach for calculating pathloss by using the finite difference time domain and transmission line matrix models of wave propagation on a grid with points separated by distances much greater than the signal wavelength. The calculated pathloss can be kept close to the true value for freespace propagation with an appropriate selection of initial conditions. This method can also simulate diffraction with an error governed by the ratio of the signal wavelength to the grid spacing.},

doi = {10.1109/TAP.2017.2657494},

journal = {IEEE Transactions on Antennas and Propagation},

number = 4,

volume = 65,

place = {United States},

year = {Fri Feb 24 00:00:00 EST 2017},

month = {Fri Feb 24 00:00:00 EST 2017}

}