Enhancement of Tools for Design of Antennas for Mobile Devices

2003 Clemson SURE Program

Presented By: Robert J. Loeven

Advisor: Dr. Anthony Martin

Modern Mobile Device Antennas Very Small Multi-Band Used in Cell Phones,

Wireless Laptops, etc. PIFA – Planar Inverted

F-type Antenna

Project Goals

Use MATLAB to model antenna structures and performance, using Makarov programs Antenna and EM Modeling, Sergey N. Makarov, John Wiley and Sons Inc. 2002

Alter Makarov programs to show more detail and enhance quality of output

Use new programs to analyze antennas, specifically patch antennas designed for cell phones and wireless notebook connections

Triangular Surface-Patch Meshes and the Rao-Wilton-Glisson Basis Functions First requires a 3D

“Mesh” antenna structure which can be created using MATLAB PDE Toolbox

Plate Example

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RWG1.m

RWG2.m

RWG3.m

RWG4.m

RWG5.m

AntennaMesh

Mesh1.mat

Mesh2.mat

Imedance.mat

Current.mat

These two routinesgenerally are devotedto geometry setup and

bookkeeping tasks

Fills the all-importantimpedance matrix [Z]

Solve system ofequations for the

current coefficients [I]

Displays graph of theantenna with surface

currents included

Efield1.m

Efield2.m

Efield3.m

Mesh2.mat (Antennamesh)

Current.mat (AntennaCurrent Density)

Computes thefield at a point in

space

Conputesradiation intensityU over a facetedspherical surface

Creates 2D PolarPlots

Point.m

Point.m

Point.m

Equations

Surface Currents –

Current Interpolation

( / 2 ) ( ),

( / 2 ) ( ),

0, otherwise

m m m m

m m m m m

l A T

l A T

r r

f r r r

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2 3

Bowtie Example to Demonstrate Color Modifications in RWG5.m and plotcurr5.m

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Bowtie – RWG5 - Old vs. New

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Bowtie Example – New Plotcurr5 Output

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3D Far-Field Patterns: Old Efield2.m

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New Efield3D.m with Antenna and Transparency

Efield3D.m 3D Rotation

Simulated Dipole Frequency Sweep

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Dipole Frequency Demonstration λ/2 (75MHz) λ (150MHz)

3λ/2 (225MHz)

2λ (300 MHz)

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Patch Antenna Design Simulation

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Frequency Sweep Results 500 MHz to 6 GHz

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resis

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Current Distribution at 2 GHz

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Patch Antenna E-Field

Patch E-field with Antenna Included

E-Shaped Patch Antenna Simulation

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E-Shape Analysis

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E-Shape Surface Currents

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E-Shape 3D E-Field

E-Shape 3D with Antenna Included

Future Work

Speed up code by using matrix interpolation

Modify plotcurr5.m code to work in 3D

Modify codes to allow for the inclusion of dielectric materials into the antennas

Use program to simulate and study real world antenna designs