1. Multi-Parametric Antenna Test Visualization for Optimization Session Information Here
Dr. Eric K. Walton The Ohio State University; ElectroScience Laboratory Columbus, Ohio
Dr. Wladimiro Villarroel AGC Automotive Americas R&D Ypsilanti, MI

2. INTRODUCTION
There are a large number of antennas needed for modern automotive communications systems
AM, FM, FM diversity
TV & TV diversity
Remote keyless entry/start
Cellular; Bluetooth
Automatic toll systems
Smart highway information systems
GPS and GPS information systems (traffic information)
Radar systems (backup, side impact, lane departure, intelligent cruise control)).
Manufacturers are looking for ways to reduce the total number of such antennas by using combinations of a smaller number of antennas.
This paper will discuss a software approach that permits the engineer to visualize the antenna performance effects of variations in geometry for a group of antennas based on either test data or simulation.

3. ACKNOWLEDGEMENT
MUCH OF THIS WORK IS TAKEN FROM AN UNDERGRADUATE INTERN PROJECT BY
MR. RYAN TOKOLA
A 2009 UNDERGRADUATE INTERN
AT THE OHIO ST. UNIV. ELECTROSCIENCE LAB.
THE PROJECT WAS SUPPORTED BY
AGC AMERICA INC., YPSILANTI, MI.

4. AGC AMERICA Asahi Glass Company (AGC) A core Mitsubishi company
World-class manufacturer and innovator in the fields of glass and fluorine chemistry
AGC Automotive Americas R&D, Inc.
AGC subsidiary in Ypsilanti, Michigan
Dedicated to the development of new technologies and new products for processed automotive glass 4

5. Why Designing Car Antennas is Difficult
On-glass (conformal) antennas are becoming more popular
Low-cost
Easy to manufacture
Unobtrusive
Limited available set of possible locations
Must have minimal visual obstruction on side and rear windows
Limited to fade band of windshield 5

6. Why Designing Car Antennas Is Difficult
Even a simple antenna has a very large number of possible geometric distributions
Today's codes can predict the performance of an antenna, but not “design” an antenna 6

7. EXAMPLE PARAMETRIC VARIABLES
INTERCONNECTION
LOCATION
FEED POINT LOCATION
THERE IS ALSO AN ANTENNA IN THE FRONT OR SIDE
ELEMENT
LENGTHS
FOR EACH PARAMETER, THERE ARE DIFFERENCES IN THE GAIN PATTERN AND IMPEDANCES
THUS THERE ARE A VERY LARGE NUMBER OF POSSIBLE COMBINATIONS AND PERMUTATIONS
WE NEED A WAY TO CHOOSE THE BEST.

8. VISUALIZATION MOTIVATION
Simply plugging a cost function into an optimization algorithm is insufficient. Human interaction (judgment) is required to:
Refine the cost function
Analyze the solution space and determine which optimization algorithms are appropriate
Identify regions of interest for optimization 8

9. Software Outline The software has the following sequence: Using
Theoretical modeling data sets
Experimental measurement data sets.
Create a data set of antenna gain performance as a function of
Polarization
Frequency
Increments in antenna geometry
Graphically Display the Consequences
Gain vs. Azimuth vs. Antenna wire locations
Polarization vs. Azimuth vs. Antenna wire locations
Overall dual antenna gain vs. Azimuth
As diversity
As phase combined
Cost function behavior
Vs. wire and interconnect locations
Vs. antenna 1 and antenna 2

10. GUI TO DEFINE PARAMETERS FOR A THEORETICAL MODEL (ESP5)
WE DEFINE ANTENNA WIRES WITH PARAMETRIC GEOMETRICAL INCREMENTS

11. Setup and Simulation
Each endpoint may be swept in one or two directions
Example: [min = -4, step = 2, max = 4] results in five simulations with the wire endpoint at {-4, -2, 0, 2, 4}
step = 0 if not swept
“xxxx” indicates unnecessary info
(vert. wires have only one x-coordinate, horiz. wires have only one y-coordinate)

12. DISPLAY THE WIRE LAYOUT FOR EACH ANTENNA

13. DEFINE THE VEHICLE AND INSERT THE ANTENNA
VEHICLE WIRE GRID MODEL WITH INITIAL ANTENNA GEOMETRY
INSERTED
ANTENNAS
EXAMPLE FOR SEDAN
USER CAN DOUBLE CHECK THE LAYOUT
PRIOR TO THE (OVERNIGHT) CALCULATION

14. SUB-SCALE MEASUREMENTS
FOR COMPARISON
GROUND
PLANE
NOT
SHOWN

15. Example Simulation for a Van:15
Example Simulation for a Van:
Created using make car mesh of VAAR Z Z Y X X Y
EXAMPLE FOR VAN
GMC Van Mesh Wireframe with Front & Rear Antenna Apertures

16. Measurement of a full scale van
WE CAN COMPARE MEASUREMENT AND SIMULATION

17. Data Visualization
User-defined functions have access to four arrays of data for each specific parameter combinations:
FGth (Vertically polarized gain of front antenna)
FGph (Horizontally polarized gain of front antenna)
RGth (Vertically polarized gain of rear antenna)
RGph (Horizontally polarized gain of rear antenna)
Each of these is a 1x360 array giving the 360° azimuthal antenna radiation pattern in dBi 17

18. GUI FOR SETTING UP PARTICULAR VISUALIZATION

19. Data Visualization
User-defined variables (a-f) can contain FGth, FGph, RGth, RGph, or any previous variable (b can contain a as an argument)
Any MATLAB functions (max, mean, etc.) can be used 19

20. Comparing Data Visualizations

21. EXAMPLE VISUALIZATION ( AZIMUTH PLOTS)
FGph
a=FGth
Plot(a)
a=FGph
b=RGph
c=max(a,b)
d=FGth
e=RGth
f=max(d,e)
Plot:Max(c,f)
a=RGph
Plot(a)

22. EXAMPLE: GAIN VS. FREQ. & AZIMUTH

23. VISUALIZATIONS FOR MEAN REAR GAIN (φ POL) AND MIN OF MAX
a=RGph
Plot(mean(a))
WIRE
LOCATION
a=FGph; b=RGph; c=max(a,b)
d=FGth; e=RGth; f=max(d,e)
Plot(min(max(c,f))
FREQ

24. Optimum Antenna Configuration
Mean front antenna gain phi & theta of wire location vs. frequency
Minimum front antenna gain phi & theta of wire location vs. frequency
Maximum front antenna gain phi & theta of wire location vs. frequency

25. Conclusion (What I’ve Learned & Where I’m Going)25
Conclusion (What I’ve Learned & Where I’m Going)
Ryan’s code has shown a considerable amount of thought and effort using programming and antenna theory to visualize & then optimize an antenna configuration on a vehicle.
Future studies
Study various types of cost functions and there impact on antenna configuration.
Modify the code to allow the user to create only one antenna.
Modify the code to allow the user to have an antenna with static geometry.
Finally we plan to discuss future project options with AGC personnel.
Comments & Questions

26. References
[1] Kraus J. D. and R. J. Marhefka, Antennas for All Applications, 3rd Ed., McGraw-Hill, N.Y., N. Y., 2002.
[2] Abou-Jaoude, R., and Walton, E. K., “Numerical Modeling of On-Glass Conformal Automobile Antennas”, IEEE Trans. Antennas Prop., vol. 46, pp , June 1998
[3] Tokola, Ryan and Walton E. K., “Visualization Software for Vehicle Antenna Design,” OSU ElectroScience Laboratory Department of Electrical and Computer Engineering, Columbus, Ohio, Technical Report and , January 29, 2010
[4] Newman, E.H., “A User’s Manual for The Electromagnetic Surface Patch Code ESP Version 5”, Technical Report , The Ohio State University ElectroScience Laboratory, Department of Electrical Engineering, 1995