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 77843-3118Email: 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

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

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

Our System: Pressure Driven Vascular

Network No Bias/Control Wires Continuous Tuning Integrated into Substrate

Reconfigurable Microstrip Parasitic Array [10]

PIN diode-based reconfigurable antenna [8]

Methodology

Examined concepts for colloidal material with electrical double layer

Perform experiments on microfluidically reconfigurable antenna array

Electromagnetically Functionalized Colloidal Dispersions (EFCDs)

Barium Strontium Titanate (BSTO)– High dielectric constant– Low losses– Availability

Oil– Low losses– Easily varied viscosity– Availability

Surfactant– Prevents material aggregation

Materials

Oil

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

Electric Fields produced by particles

eE

[5]

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)

Maxwell Garnett Mixing Rule

3

2i e

eff e e

i e i e

S SS S S

S S S S

Maxwell Garnett Mixing Rule Equation [9]

εe = 5

εi = 80

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

Permittivity Example

εfεp

1V -1VL=1, r=0.1

Permittivity Example Results

Case 2:

εf=100ε0, εp=10ε0

Case 1:

εf=100ε0, εp=1000ε0

Model the fluid and particle flow for the antenna– Find effective properties of fluid flowing around particles

Materials Team Goal

εpεp

εp

εf

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:

Permittivity matrix is in the form of the identity matrix

y

x

y

x

E

E

D

D

2221

1211

0

0

2D COMSOL Results

f COMSOL MG % Error0.1 2.56 2.80 8.410.2 3.14 3.66 14.270.3 3.89 4.78 18.550.4 4.96 6.26 20.720.5 6.43 8.32 22.73

Voltage varying in X-direction

Voltage varying in Y-direction

50%

3D COMSOL Results

f COMSOL MG % Error0.1 2.79 2.80 0.180.2 3.67 3.66 0.200.3 4.87 4.78 1.970.4 6.79 6.26 8.53

0.45 8.47 7.20 17.70

10%

1001 1003 1005 1007 1009 1011

Fo

rce

(10-1

7N

)

120

100

80

60

40

20

0

Frequency Effects on Particle

A particle between two electrodes with AC voltage will receive a force dependent upon frequency

V

V=0

Patch Antenna Background

Substrate clad with two conductive layers

Resonant frequency based on dimensions and substrate properties

Coaxial probe used as transmission line

Lowest order mode (TE10)

Electric Distribution Radiation as a result of fringe fields

Single Patch Antenna [7] Transmission Line and Electric Field [7]

Calculations: Matlab

Equations used for very 1st order approximations Implemented equations in Matlab

Length of Patch 28.29mm

Width of Patch 36.96mm

Matlab Calculation Results Graph – Antenna Length vs. Frequency

2

2 1o

pr r

vW

f

Antenna Equations

Lf

Looeffr

p 22

1

[6]

[6]

HFSS Modeling

HFSS – Electromagnetic simulator and CAD software Simulated single patch antenna Obtain better approximations for length and probe positioning

HFSS Single Patch Antenna Model

HFSS Simulated Results

Length of Patch 27.9mm

Width of Patch 37mm

a (Distance from Edge)

5.7mm

HFSS Modeling Results1

1SWRV

VSWR plot: 1 corresponds to 100% power transmitted Water wave hitting a wall

Smith Chart: 1 corresponds to all min on VSWR Bulls eye

1

1VSWR

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 Mix and Bake Substrate Solder Probes to Ground Plane

Complete Antenna Structure Solder Probe and Overlapping Copper Tape

Cut Copper Tape and Attach to Substrate

Material Preparation

Gather Materials Weigh EFCD, Surfactant and Oil

Input material into syringe

Mix Material with Vortex Machine

Place Material in Sonicator

Place syringe in system syringe pump

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

Smith Chart VSWR Plot

(GHz)

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

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

[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 BarreraThird Row: Justin Marshall and Cameron Peters

Second Row: Rachel Anderson, Amy Bolon, and Stephen DavisFront Row: Sean Goldberger, David Umana, Jamie Edelen, and Frank Drummond