SIMULATION OF A FM BAND SELF-STRUCTURING ANTENNA IN AN AUTOMOBILE - - PDF document

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SIMULATION OF A FM BAND SELF-STRUCTURING ANTENNA IN AN AUTOMOBILE - - PDF document

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SIMULATION OF A FM BAND SELF-STRUCTURING ANTENNA IN AN AUTOMOBILE ENVIRONENT B. T. Perry*, E.J. Rothwell J. E. Ross L.L. Nagy ECE Department John Ross & Associates Delphi Research Labs Michigan State University 422 N. Chicago Street

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SLIDE 1

SIMULATION OF A FM BAND SELF-STRUCTURING ANTENNA IN AN AUTOMOBILE ENVIRONENT

  • B. T. Perry*, E.J. Rothwell
  • J. E. Ross

L.L. Nagy ECE Department John Ross & Associates Delphi Research Labs Michigan State University 422 N. Chicago Street 51786 Shelby Pkwy East Lansing, MI 48824 Salt Lake City, Utah Shelby Township, MI rothwell@egr.msu.edu johnross@johnross.com Antennas are often placed in environments where their interaction with surrounding objects effects their overall performance. Some are deployed in environments where the designer is unsure of the effect on the performance of the

  • antenna. This is especially true in automotive applications where the car body, as

well as other components of the vehicle, play a role in the functionality of the

  • antennas. Self-structuring antennas (SSAs) are subject to this uncertainty during

their design and analysis. For this reason, a simulation-based assessment of a self-structuring antenna placed in the rear window of an automobile was undertaken. Using GA-NEC, a software package developed by John Ross & Associates, the states of the self-structuring antenna are chosen by way of a genetic algorithm. Chromosomes used in the GA consist of the states of switches residing on the self-structuring antenna template. Variations in the switch states give rise to changes in the electrical shape of the antenna, as described in previous work on the subject of SSAs. Analysis is done using NEC in the FM band (88-108MHz). Performance criteria such as input impedance, VSWR, and gain are used in the determination of the fitness of a certain SSA state. The simulation of SSAs presented here is meant to provide a cost effective approach to the design of self-structuring antennas in environments that are not

  • ptimal for performance of an antenna. This study helps to provide a framework

for a simulation-based approach to the study of self-structuring antennas in various environments, including automotive applications. As a specific example, an SSA placed in the upper rear window of a vehicle is considered. The results are compared to the simulation of a passive backlight antenna placed in the same environment.

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SLIDE 2

SIMULATION OF A FM BAND SELF-STRUCTURING ANTENNA IN AN AUTOMOBILE ENVIRONENT

  • B. T. Perry*, E.J. Rothwell
  • J. E. Ross

L.L. Nagy ECE Department John Ross & Associates Delphi Research Labs Michigan State University 422 N. Chicago Street 51786 Shelby Pkwy East Lansing, MI 48824 Salt Lake City, Utah Shelby Township, MI rothwell@egr.msu.edu johnross@johnross.com

  • 1. Commission and session topic: B1.1 Antenna Analysis and Design
  • 2. Required presentation equipment: PowerPoint display
  • 3. Corresponding author:

Edward J. Rothwell Department of Electrical and Computer Engineering Michigan State University East Lansing, MI 48824 Phone: 517-355-5231 e-mail: rothwell@egr.msu.edu FAX: 517-353-1980

  • 6. New knowledge contributed by paper: This is the first comprehensive

examination of the effect of an automobile on the performance of a self-structuring antenna.

  • 7. Relationship to previous work: Self-structuring antennas were introduced by

the authors at the 2000, 2001, and 2002 URSI National Radio Science Meetings. The basic operation and analysis of the antenna were described in these papers.

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SLIDE 3

1 June 24, 2003

Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment

B.T. Perry*, E.J. Rothwell, L.C. Kempel Department of Electrical and Computer Engineering Michigan State University, East Lansing, MI J.E. Ross John Ross & Associates, Salt Lake City, UT L.L.Nagy Delphi Research Labs, Shelby Township, MI URSI B Session 56: Vehicle Electromagnetics and Inverse Scattering Tuesday, June 24, 2003 8:00 a.m. Knox

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SLIDE 4

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 2

Overview

Self-Structuring Antenna (SSA) Overview Goals Motivation Automobile Environment Simulation Results Conclusions Future Work

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SLIDE 5

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 3

SSA Overview

The SSA automatically configures itself to accommodate changes in signal strength, orientation, and atmospheric conditions through the control of simple on/off switches Changes in switch states cause the electrical shape of the antenna to be altered, allowing it to adjust to changes in its electromagnetic environment The effect of different antenna configurations is unknown to the designer, only a statistical approach is utilized in testing

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SLIDE 6

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 4

Goals of Research

Application of self-structuring antennas in automobile environments Gauge the interaction of the self-structuring antenna with components of the automobile, such as the heater grid and the car body

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SLIDE 7

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 5

Motivation

High end automobiles built today can have 11 or more antennas

FM Radio (multiple) AM Radio (multiple) GPS Satellite Radio Cellular Telephone Keyless Entry Television

Self-structuring antennas could be used to replace multiple antennas

Savings in both money and space Multitasking-broadband antennas

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SLIDE 8

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 6

Automobile Environment

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SLIDE 9

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 7

Automobile Environment

Heater Grid Self-Structuring Antenna Rear Window Frame Antenna Feed

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SLIDE 10

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 8

Simulation Results

Self-Structuring Antenna over a ground plane VSWR vs. Frequency Optimized for constrained VSWR between 1 and 3 across the FM Band simultaneously Approximate Antenna Size

0.33? by 0.05? at 100 MHz

88 90 92 94 96 98 100 102 104 106 108 Frequency (MHz) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 VSWR First Configuration Second Configuration

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SLIDE 11

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 9

Simulation Results

Current Distribution for Self Structuring Antenna

  • ver a ground plane

92 MHz VSWR of 1.56 VSWR of 15.8

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SLIDE 12

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 10

Simulation Results

Self-Structuring Antenna on Car without Heater Grid VSWR vs. Frequency

88 90 92 94 96 98 100 102 104 106 108 Frequency (MHz) 1 2 3 4 5 6 7 VSWR First Configuration Second Configuration

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SLIDE 13

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 11

Simulation Results SSA on Car – 88 MHz

VSWR of 4.03 VSWR of 6.67

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SLIDE 14

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 12

Simulation Results SSA on Car – 88 MHz

VSWR of 4.03 VSWR of 6.67

Elevation

E - Theta E - Phi

Elevation

E - Theta E - Phi

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SLIDE 15

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 13

Simulation Results SSA on Car – 88 MHz

VSWR of 4.03 VSWR of 6.67

Azimuthal

E - Theta

Azimuthal

E - Theta

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SLIDE 16

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 14

Simulation Results SSA on Car – 108 MHz

VSWR of 3.33 VSWR of 1.47

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SLIDE 17

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 15

Simulation Results SSA on Car – 108 MHz

VSWR of 3.33 VSWR of 1.47

Azimuthal

E - Theta

Azimuthal

E - Theta

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SLIDE 18

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 16

Simulation Results

SSA on Car with Heater Grid VSWR vs. Frequency

88 90 92 94 96 98 100 102 104 106 108 Frequency (MHz) 1 2 3 4 VSWR First Configuration Second Configuration

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SLIDE 19

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 17

Simulation Results SSA and Heater on Car – 88 MHz

VSWR of 3.19 VSWR of 2.71

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SLIDE 20

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 18

Simulation Results SSA and Heater on Car – 88 MHz

VSWR of 3.19 VSWR of 2.71

Azimuthal

E - Theta

Azimuthal

E - Theta

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SLIDE 21

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 19

Simulation Results SSA and Heater on Car - 108 MHz

VSWR of 1.50 VSWR of 3.99

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SLIDE 22

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 20

Simulation Results SSA and Heater on Car - 108 MHz

VSWR of 1.50 VSWR of 3.99

Azimuthal

E - Theta

Azimuthal

E - Theta

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SLIDE 23

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 21

Simulation Results

Self Structuring Antenna on Car without Heater Grid Optimized for VSWR less than 1.1 at individual frequencies

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 88 92 96 100 104 108 Frequency (MHz) VSWR

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SLIDE 24

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 22

Simulation Results

Self Structuring Antenna on Car without Heater Grid – 88 MHz Optimized for VSWR less than 1.1 at individual frequencies

Elevation - 88 MHz

E - Theta E - Phi

Azimuthal - 88 MHz

E - Theta

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SLIDE 25

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 23

Simulation Results

Self Structuring Antenna on Car without Heater Grid – 108 MHz Optimized for VSWR less than 1.1 at individual frequencies

Elevation - 108 MHz

E - Theta E - Phi

Azimuthal - 108 MHz

E - Theta

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SLIDE 26

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 24

Simulation Results

Self Structuring Antenna on Car with Heater Grid Optimized for VSWR less than 1.1 at individual frequencies

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 88 92 96 100 104 108 Frequency (MHz) VSWR

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SLIDE 27

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 25

Simulation Results

Self Structuring Antenna on Car with Heater Grid – 88 MHz Optimized for VSWR less than 1.1 at individual frequencies

Elevation - 88 MHz

E - Theta E - Phi E - Theta

Azimuthal - 88 MHz

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SLIDE 28

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 26

Simulation Results

Self Structuring Antenna on Car with Heater Grid – 108 MHz Optimized for VSWR less than 1.1 at individual frequencies

Elevation - 108 MHz

E - Theta E - Phi

Azimuthal - 108 MHz

E - Theta

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SLIDE 29

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 27

Conclusions

Algorithm converged faster and to a lower VSWR for increasingly complex environments when optimized for the entire FM Band VSWR decreased when the SSA interacted strongly with the Car and Heater Grid Optimization at individual frequencies yielded better results, i.e. lower VSWR and better convergence, than optimizing for the entire FM Band

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SLIDE 30

June 24, 2003 2003 AP-S/URSI Symposium -- Simulation of a FM Band Self-Structuring Antenna in an Automobile Environment 28

Future Work

Optimization based on pattern measurements and VSWR simultaneously Study of various switch models Alternative placement of the SSA