Multifunctional Materials Antenna
Array Team
Rachel Anderson, JD Barrera, Amy Bolon,
Stephen Davis, Jamie Edelen, Justin Marshall,
Cameron Peters, David Umana
Frank Drummond, Sean Goldberger
Dr. Gregory H. Huff
Dr. Patrick Fink, Tim Kennedy, Phong Ngo
Space Engineering Institute
Texas A&M University
College Station, TX 77843-3118
Email: ghuff@tamu.edu
Team Breakdown
Materials Team
– Amy Bolon, Senior
Mechanical Engineering
– Stephen Davis,
Sophomore Aerospace
Engineering
– Cameron Peters,
Freshman Aerospace
Engineering
Antenna Team
– Rachel Anderson, Senior
Electrical Engineering
– JD Barrera, Senior
Electrical Engineering
– Jamie Edelen, Freshman
Computer Engineering
– Justin Marshall, Senior
Electrical Engineering
– David Umana, Freshman
Electrical Engineering
Graduate Mentors
– Frank Drummond, Aerospace Engineering
– Sean Goldberger, Electrical Engineering
Outline
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Motivation
Project Goals
Methodology
Materials
Antennas
Integrated System
Results
Future Work
Questions
Motivation
NASA JSC Needs
 Advanced airborne and
space-based platforms
 Antennas that utilize the
electromagnetic spectrum
more effectively
 Operating at multiple
frequencies
 Communication on
multiple channels
Project Goals
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Investigate multidisciplinary concepts, materials, and measurements needed to
simultaneously reconfigure the antenna array
Design and fabricate a 1x2 array of reconfigurable microstrip patch antennas
using electromagnetically functionalized colloidal dispersions (EFCDs)
Determine the limits of reconfiguration and electromagnetic visibility of colloidal
dispersions with different material systems (dielectric, magnetic, etc.)
System Diagram
Reconfigurable Antennas
Other Systems:
 Uses PIN diode switches or
Microelectromechanical
systems (MEMS) actuator
 Thermal issues
Reconfigurable Microstrip Parasitic Array [10]
Our System:
 Pressure Driven Vascular
Network
 No Bias/Control Wires
 Continuous Tuning
 Integrated into Substrate
PIN diode-based reconfigurable antenna [8]
Methodology
Examined concepts for colloidal material with electrical double layer
Materials Team
-Obtain effective
properties of
microfluidic system
-Examine effects of
frequency on the
electrical force
-Prepare EFCDs
Antenna Team
-Develop analytical
model for antenna
-Study materials and
hardware
-Design reconfigurable
antenna array
Perform experiments on microfluidically reconfigurable antenna array
Materials
 Electromagnetically Functionalized Colloidal
Dispersions (EFCDs)
 Barium Strontium Titanate (BSTO)
– High dielectric constant
– Low losses
– Availability
Oil
 Oil
– Low losses
– Easily varied viscosity
– Availability
 Surfactant
– Prevents material aggregation
BSTO
Surfactant
Materials
 Permittivity – describes how an electric field affects
and is affected by a dielectric material
– High permittivity reduces electric field present
 Colloids – system involving small particles of one
substance suspended in another
– ex: milk, Styrofoam, mist
 Surfactant creates the electrical double layer around
the BSTO particles, which deters aggregation
[2]
[3]
Electrostatics
 Gauss’s Law
– Assuming linear dielectric, no magnetic field
– Governing equation used for modeling
 

  E  e
 Electric Fields produced by particles
[5]
Maxwell Garnett Mixing Rule
 Calculate the effective material properties for a colloidal
mixture (permittivity, permeability)
 For non-ideal systems, have to consider:
– Shape (spheres, discs or needles)
– Heterogeneous inclusions (layered sphere)
– Polydispersity (various shapes, sizes and masses)
Seff
Si  S e
 Se  3Se
Si  2 S e    Si  S e 
Maxwell Garnett Mixing Rule Equation [9]
εe = 5
εi = 80
Permittivity Example
 Studied the relationship between permittivity and the
electric field
 Greater permittivities reduces the effect of the electric
field
 Problem set up:
– Single particle within a fluid, voltages on either end
– Particle and fluid have different permittivities
εp
1V
εf
L=1, r=0.1
-1V
Permittivity Example Results
 Case 1:
εf=100ε0, εp=1000ε0
 Case 2:
εf=100ε0, εp=10ε0
Materials Team Goal
 Model the fluid and particle flow for the antenna
– Find effective properties of fluid flowing around particles
εp
εp
εf
εp
εeff
Effective Properties Calculation
 Using periodic boundary conditions to solve for the
effective permittivity of the colloidal fluid
 Vary direction of voltage flow to solve for the electric
field (E) and electric displacement (D) in the x and y
directions
– Solve the following equation:
 Dx  11 012   Ex 
D   
E 

 y  021  22   y 
 Permittivity matrix is in the form of the identity matrix
2D COMSOL Results
50%
Voltage varying
in Y-direction
f
0.1
0.2
0.3
0.4
0.5
COMSOL
2.56
3.14
3.89
4.96
6.43
Voltage varying
in X-direction
MG
2.80
3.66
4.78
6.26
8.32
% Error
8.41
14.27
18.55
20.72
22.73
3D COMSOL Results
10%
f
0.1
0.2
0.3
0.4
0.45
COMSOL
2.79
3.67
4.87
6.79
8.47
MG
2.80
3.66
4.78
6.26
7.20
% Error
0.18
0.20
1.97
8.53
17.70
Frequency Effects on Particle
 A particle between two electrodes with AC voltage
will receive a force dependent upon frequency
120
V
100
Force (10-17N)
80
60
40
V=0
20
0
1001
1003
1005
1007
1009
1011
Patch Antenna Background
Single Patch Antenna [7]
 Substrate clad with two
conductive layers
 Resonant frequency based on
dimensions and substrate
properties
Transmission Line and Electric Field [7]
 Coaxial probe used as transmission
line
 Lowest order mode (TE10)
 Electric Distribution
 Radiation as a result of fringe fields
Calculations: Matlab
Lp 
1
2 f r  eff
vo
Wp 
2 fr
 o o
 2L
2
r 1
[6]
[6]
Antenna Equations
Length of Patch 28.29mm
Width of Patch
36.96mm
Matlab Calculation Results
Graph – Antenna Length vs. Frequency
 Equations used for very 1st order approximations
 Implemented equations in Matlab
HFSS Modeling
Length of Patch 27.9mm
Width of Patch
37mm
a (Distance
from Edge)
5.7mm
HFSS Simulated Results
HFSS Single Patch Antenna Model
 HFSS – Electromagnetic simulator and CAD software
 Simulated single patch antenna
 Obtain better approximations for length and probe positioning
VSWR 
1 
1 
HFSS Modeling Results
 VSWR plot: 1 corresponds to 100% power transmitted
 Water wave hitting a wall
 Smith Chart: 1 corresponds to all min on VSWR
 Bulls eye
VSWR 
1 
1 
Current Research
Integration of Vascular Reconfiguration Mechanisms in a Microstrip Patch Antenna, G. H. Huff and S. Goldberger,
in review IEEE Antennas and Wireless Propagation Letters, submitted Nov. 2007
Patch Array
Antenna Fabrication
Construct Substrate Mold
Complete Antenna Structure
Mix and Bake Substrate
Solder Probe and
Overlapping Copper Tape
Solder Probes to Ground Plane
Cut Copper Tape and Attach
to Substrate
Material Preparation
Gather Materials
Place syringe in system
syringe pump
Weigh EFCD,
Surfactant and Oil
Input material
into syringe
Mix Material with Vortex Machine
Place Material in
Sonicator
Reconfigurable Antenna System
Entire Reconfigurable Antenna Setup
 System connected by tubing, valves and Y-splitters
 Inner capillary of antenna filled with oil
 EFCD material flows through outer capillaries of antenna
Results
Microstrip Patch Array: Experimental Model (3 GHz Design)
Results
(GHz)
Smith Chart
VSWR Plot
Resonant frequency decreased 150MHz
as EFCD introduced into antenna system
Small Array Behavior of Frequency Reconfigurable Antennas Enabled by Functionalized Dispersions of Colloidal Materials,
Sean Goldberger and G. H. Huff, in proc. 2009 URSI North American Radio Science Meeting, Boulder, CO, Jan. 2009
Future Work
 Poly-dispersal systems
 Different EFCD particle
shapes
 Different antenna
designs
 Materials
 Feasibility testing of
system in dynamic
environment
 Closed loop system
 Zero gravity testing
NASA KC-135 [3]
Acknowledgements
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Dr. Gregory H. Huff
Dr. Patrick Fink
Tim Kennedy
Phong Ngo
Dr. James G. Boyd
Mrs. Magda Lagoudas
Stephen A. Long
Jacob McDonald
Bolutife P. Ajayi
Frank Drummond
Sean Goldberger
References
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[1] Ansoft, HFSS© v11.1.2, Pittsburgh, PA 15219
[2] "Capacitor." Chemistry Daily. 4 Jan. 2007. Oct. 2008 <http://www.chemistrydaily.com/chemistry/capacitor>.
[3] Cowing, Keith. "Weightless Over Cleveland - Part 1: Floating Teachers." SpaceRef.com. 1 Oct. 2006. 20 Nov. 2008
<www.spaceref.com/news/viewnews.html?id=1159>.
[4] Davis, Doug. "Gauss's Law." General Physics II. 2002. 20 Nov. 2008
<http://www.ux1.eiu.edu/~cfadd/1360/24gauss/gauss.html>.
[5] "Electrostatic Charge and Bacterial Adhesion." Bite-Sized Tutorials. 7 Nov. 2008
<www.ncl.ac.uk/.../tutorials/electrostatic.htm>.
[6] Goldberger, Sean. “Microstrip Patch Antenna Design using a Hybrid Transmission Line and Cavity Model,” Class
report, Dept. of Elec. and Comp. Engineering, Texas A&M Univ., College Station, Texas, 2008.
[7] Long, S. A. “A Cognitive Compensation Mechanism for Deformable Antennas,” M.S. thesis, Dept. of Elec. and
Comp. Engineering, Texas A&M Univ., College Station, Texas, 2008.
[8] Piazza, Daniele, Nicholas J. Kirsch, Antonio Forenza, Robert W. Heath, Jr., and Kapil R. Dandekar. “Design and
Evaluation of Reconfigurable Antenna Array for MIMO Systems." IEEE TRANSACTIONS ON ANTENNAS AND
PROPAGATION 56 (2008): 869-881.
[9] Sihvola, A. Electromagnetic Mixing Formulas and Applications. Washington, D.C.: Institution of Engineering and
Technology (IET), 1999. 40-78.
[10] Zhang, S., G. H. Huff, J. Feng, and J. T. Bernhard. "A Pattern Reconfigurable Microstrip Parasitic Array." IEEE
TRANSACTIONS ON ANTENNAS AND PROPAGATION 52 (2004): 2773-2776.
Project Team
Back Center: Joel Barrera
Third Row: Justin Marshall and Cameron Peters
Second Row: Rachel Anderson, Amy Bolon, and Stephen Davis
Front Row: Sean Goldberger, David Umana, Jamie Edelen, and Frank Drummond