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: [email protected]
Advisor: Dr. Mohammod Ali
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
Biography
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Outline
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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
Introduction
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Personal Communication
Systems
Mobile Data System
GPS
Commercial & Defense Applications
UAV
Satellite
Dual band antenna on Modified ground plane
Novel Design Concept for Mobile Antennas
Dual band antenna on Conventional ground plane
Application: Mobile Antennas
Printed internal antenna
Cell phone back cover
Proposed a Novel Slow-wave Structure
90 mm
35 mm
h=10 mm
Feed
Metal Ground
Antenna
Ground90 mm
h=4 mm
FeedGround
Metal Gap Antenna
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Novel Design Concept for Mobile Antennas
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.
Antenna prototype
Accomplishments 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
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Current Distribution
Conventional Antenna
Proposed Antenna
Higher Current Density
Maximum Current
Minimum Current
Antenna Miniaturization using Engineered Structures
Applications of Dipole Antenna Array
Ground-based
Vehicular
Air-borne applications
Z
X
height ≈ 0.25 wavelength
Array of Dipole Antennas
Dielectric substrate
Metal Ground
Conventional Dipole Array Configuration
UAV
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Antenna Miniaturization using Engineered Structures
Thin antenna structure Light-weight and compact Directional Wideband
Dipole Antenna
h= 0.01 wavelength
Engineered Structure (EBG)
Goals
Challenges
Generates surface wave
Costly Increases Radar Cross-section
Reduces antenna efficiency
Requires 0.25 wavelength height
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Metal plates
Dipole Antenna
Metal Ground
Proposed Solution
Phase Profile of EBG Structures
Antenna Miniaturization using Engineered Structures
Ph
ase
(Deg
rees
)
Frequency (GHz)
Metal Ground
EBG Surface
Phase profile
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h << λ/4
In phase
Engineered Structure
h < λ/4
Out of phase
Dielectric Substrate
Antenna
In phase
h =
λ/4
Direct wave
Reflected wave
Metal Ground
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).
EBG Top View
Dipole Antenna Balun circuitry
Coaxial cable
Accomplishments Reduced antenna height by 9 times
Attained sufficient antenna bandwidth
Increased antenna Gain and Efficiency
Antenna Miniaturization using Engineered Structures
Dipole Antenna Performance on Proposed EBG Structure
2.8 mm ≡ 0.03λ
Metal PlatesDipole Antenna
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Ref
lect
ion
(d
ecib
els)
Novel Planar EBG Structures
Applications: Planar EBG
▪ Mobile phones ▪ Wireless LAN ▪ Satellite ▪ JTRS ▪ Global Positioning System
Stopband3.5 – 4.5 GHz
Top-view
Advantages: Planar EBG
▪ Extremely low cost
▪ Easy to fabricate
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Unit cell of proposed Planar EBG Structure
Tra
nsm
iss
ion
(d
ecib
els)
Application of Planar EBG Structures
d = 51 mm
Dielectric Substrate
Dipole Antennas
EBG Structure
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Coupling reduced by 13 dB
Mu
tual
Co
up
lin
g (
dec
ibel
s)
Application of Planar EBG Structures
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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Without EBG
Null Points – No Signal
With EBGNulls
Eliminated
Accomplishments Increased bandwidth by 31%
Reduced coupling by 13 dB
Eliminated Nulls in Radiation Pattern
Increased antenna Gain
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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