Miniaturization and Gain Enhancement of
Wideband Low-profile Antennas on
Engineered Structures
Presented by -
Faisal Abedin
(Doctoral Candidate)
Department of Electrical Engineering
University of South Carolina, Columbia, SC 29208
E-mail: abedin@engr.sc.edu
Advisor: Dr. Mohammod Ali
Biography
Education
 Doctoral Candidate (GPA: 3.92)
Major: Electrical Engineering (Start Date: Spring 2003)
Department of Electrical Engineering
University of South Carolina, Columbia, SC
 M.S. in Electrical Engineering, May 2001
Department of Electrical and Computer Engineering
North Carolina State University, Raleigh, NC
 B.S. in Electrical Engineering, September 1999
Department of Electrical Engineering
Bangladesh University of Engineering and Technology, Dhaka, Bangladesh
Research Interest
 Electromagnetic Band-gap (EBG) Structures and their Antenna Applications
 Antenna miniaturization
 Diversity antennas
2
Outline
 Introduction
 Novel concept to design ultra-thin Mobile Phone Antennas
 Introduction to Engineered Structures called Electromagnetic
Bandgap (EBG) structures
 Three-dimensional EBG structures
 Planar EBG structures
 Phase profile of EBG structures
 Application of Planar EBG structures
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Introduction
Personal
Communication
Systems
Commercial & Defense Applications
UAV
Satellite
Mobile Data
System
GPS
3
Novel Design Concept for Mobile Antennas
Printed internal antenna
Application:
Mobile Antennas
Cell phone back cover
Antenna
Metal
Gap
h=10 mm
35 mm
Antenna
h=4 mm
Metal
Ground
90 mm
Dual band antenna on
Conventional ground plane
Feed
Ground
Feed
Ground
90 mm
Proposed a Novel
Slow-wave Structure
Dual band antenna on
Modified ground plane
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Novel Design Concept for Mobile Antennas
Maximum Current
Accomplishments
Conventional
Antenna
 Increases the antenna electrical
length by uniformly spreading
current
 Increases the antenna bandwidth
by 3 to 4 times
 Reduces the antenna height by
2.5 times
Proposed
Antenna
Higher Current Density
Antenna prototype
Current Distribution
Minimum Current
M. F. Abedin and M. Ali, “Modifying the Ground Plane and its Effect on Planar Inverted-F Antennas (PIFAs) for
Mobile Phone Handsets,’’ IEEE Antennas and Wireless Propagation Letters, vol.2, no. 15, pp. 226-229, 2003. 5
Antenna Miniaturization using Engineered Structures
Applications of Dipole Antenna Array
UAV
 Ground-based
 Vehicular
 Air-borne applications
Array of Dipole Antennas
height ≈ 0.25
wavelength
Dielectric
substrate
Z
Metal Ground
X
Conventional Dipole Array Configuration
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Antenna Miniaturization using Engineered Structures
Metal plates
Challenges
Dipole
Antenna
Proposed Solution
Requires 0.25
wavelength height
Metal Ground
Costly
Increases Radar
Cross-section
Engineered Structure (EBG)
Dipole Antenna
Generates
surface wave
h= 0.01
wavelength
Reduces antenna
efficiency
Goals
 Thin antenna structure
 Light-weight and compact
 Directional
 Wideband
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Antenna Miniaturization using Engineered Structures
Phase Profile of EBG Structures
In phase
Out of phase
Reflected
wave
h = λ/4
Direct
wave
h < λ/4
Antenna
Metal Ground
Dielectric Substrate
h << λ/4
Phase (Degrees)
In phase
Phase profile
Metal Ground
EBG Surface
Engineered Structure
Frequency (GHz)
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Antenna Miniaturization using Engineered Structures
Dipole Antenna
Dipole Antenna Performance on
Proposed EBG Structure
Metal Plates
EBG Top View
Dipole Antenna
Balun
circuitry
Reflection (decibels)
2.8 mm ≡ 0.03λ
Accomplishments
 Reduced antenna height by 9 times
Coaxial
cable
 Attained sufficient antenna bandwidth
 Increased antenna Gain and Efficiency
M. F. Abedin and M. Ali, “Effects of EBG Reflection Phase Profiles on the Input Impedance and Bandwidth of
Ultra-thin Directional Dipoles,’’ IEEE Transactions on Antennas and Propagation (under revision).
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Novel Planar EBG Structures
Applications: Planar EBG
▪ Mobile phones ▪ Wireless LAN
▪ Satellite
▪ JTRS
▪ Global Positioning System
Unit cell of proposed Planar EBG Structure
Advantages: Planar EBG
▪ Extremely low cost
▪ Easy to fabricate
Transmission (decibels)
Top-view
Stopband
3.5 – 4.5 GHz
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Application of Planar EBG Structures
Dipole
Antennas
Dielectric
Substrate
Mutual Coupling (decibels)
d = 51 mm
EBG
Structure
Coupling reduced
by 13 dB
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Application of Planar EBG Structures
Without
EBG
Nulls
Eliminated
With
EBG
Null Points – No Signal
Accomplishments
 Increased bandwidth by 31%
 Reduced coupling by 13 dB
 Eliminated Nulls in Radiation Pattern
 Increased antenna Gain
M. F. Abedin and M. Ali, “Application of EBG Structures to Reduce the Mutual Coupling between Linear Antenna
Elements of an Array,’’ IEEE Antennas and Wireless Propagation Letters (submitted March 2005).
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Broader Dissemination
Actively involved in disseminating knowledge to the broader community –

Mentored two High School Seniors through SPRI program in previous years

This summer an 11th Grade student will be mentored to conduct research

An undergraduate EE student of USC will be guided this summer funded
through an NSF REU grant
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Relevant Publications
1.
M. F. Abedin and M. Ali, “Modifying the Ground Plane and its Effect on Planar Inverted-F Antennas (PIFAs) for
Mobile Phone Handsets,’’ IEEE Antennas and Wireless Propagation Letters, vol. 2, no. 15, pp. 226-229, 2003.
2.
M. F. Abedin and M. Ali, “Effects of EBG Reflection Phase Profiles on the Input Impedance and Bandwidth of
Ultra-thin Directional Dipoles,’’ IEEE Transactions on Antennas Propagation (under revision).
3.
M. F. Abedin and M. Ali, “Application of EBG Structures to Reduce the Mutual Coupling between Linear Antenna
Elements of an Array,’’ IEEE Antennas and Wireless Propagation Letters (submitted).
4.
M. Ali and M. F. Abedin, “Designing Ultra-Thin Planar Inverted-F Antennas,” in Proc. IEEE Antennas and
Propagation Society International Symposium Digest, vol. 3, pp. 78-81, Columbus, OH, June 2003.
5.
M. F. Abedin and M. Ali, “Application of EBG Substrates to Design Ultra-Thin Wideband Directional Dipoles,’’ in
Proc. IEEE Antennas and Propagation Society International Symposium, vol. 2, pp. 2071-2074, Monterey, CA,
June 2004.
6.
M. F. Abedin and M. Ali, “Designing Ultra-Thin Printed Dipole Arrays based on EBG Reflection Phase Profile,”
IEEE Wireless and Microwave Technology (WAMI) Conference 2005, Clearwater, FL, April 2005 (accepted).
7.
M. F. Abedin and M. Ali, “Reducing the Mutual-Coupling between the Elements of a Printed Dipole Array Using
Planar EBG Structures,” IEEE Antennas and Propagation Society International Symposium, Washington, DC, July
2005 (submitted).
8.
M. F. Abedin, M. Ali and P. F. Wahid, “Bandwidth, Efficiency and Pattern Characteristics of Miniaturized
Embedded Antennas at 900/1900 MHz,” 9th edition of the Biennial International Conference on Electromagnetics
in Advanced Applications.(ICEAA 2005), Torino, Italy, September 2005 (under preparation).
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