Mutual Coupling Between Coax-fed
Rectangular Microstrip Antennas Embedded
in Layered Uniaxial Anisotropic Dielectrics
Benjamin D. Braaten*
Dimitrios E. Anagnostou
Keith W. Whites
1
2
2
1. North Dakota State University, Department of Electrical and Computer Engineering, Fargo, North Dakota.2. South Dakota School of Mines and Technology, Department of Electrical and Computer Engineering, Rapid City, South Dakota.
Topics
Problem Definition
Interests and Background
Mutual Coupling Results
Single anisotropic substrate
Single anisotropic superstrate
Separated by an anisotropic layer
Discussion/Conclusion
North Dakota State University
Interests and Background
North Dakota State University
The previous problem is of interest in many fields.
Microstrip antenna arrays [1].
Frequency Selective Structures (FSS) [2].
Radio Frequency Identification (RFID) [3].
IC based antennas.
“Engineered Materials” [4].[1] David M. Pozar and Daniel H. Schaubert, “Microstrip Antennas: The analysis and Design of Microstrip Antennas and Arrays”, IEEE Press, Piscataway, NJ, 1995.
[2] A.L.P.S. Campos an A.G. d'Assuncao, “Scattering parameters of a frequency selective surface
between anisotropic dielectric layers for incident co-polarized plane waves,” IEEE Antennas and Propagation Society International Symposium, 2001, Vol. 4, July 8-13, 2001, p. 382-385.
[3] K. Finkenzeller, RFID Handbook:Fundamentals and Applications in Contactless Smart Cards and Identification, John Wiley and Sons, West Sussex, England, 2003.[4] E. A. Navarro, A. Luximon, I. J. Craddock, D. L. Paul and M. Dean, “Multilayer and conformal antennas using synthetic dielectric substrates,” IEEE Antennas and Propagation, Vol. 51, No. 4, pp. 905-908, 2003.
Microstrip Patch Results
North Dakota State University
Consider:
L = 6.55 cm,
W = 10.57 cm,
d1 = d2 = 1.58 cm
f = 1.41 GHz.
Microstrip Patch Results
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xd = 16.8 mm
zd = 52.85 mm
f = 1.41 GHz
Permittivity = 4.25
(chosen by isolating the patch)
Microstrip Patch Results
North Dakota State University
A single grounded
anisotropic
substrate
(d1 = 1.58 mm and
d2 = 0 mm.):
(Pozar) David M. Pozar and Daniel H. Schaubert, “Microstrip Antennas: The analysis and Design of Microstrip Antennas and Arrays”, IEEE Press, Piscataway, NJ, 1995.
Microstrip Patch Results
North Dakota State University
A single grounded
anisotropic
substrate
(d1 = 1.58 mm and
d2 = 0 mm.):
Microstrip Patch Results
North Dakota State University
A single
anisotropic
cover
(d1 = 1.58 mm
d2 = 1.58 mm
permittivity = 4.25):
Microstrip Patch Results
North Dakota State University
A single
anisotropic
cover
(d1 = 1.58 mm
d2 = 1.58 mm
permittivity = 4.25):
Microstrip Patch Results
North Dakota State University
Separated by a
single anisotropic
layer
(d1 = 1.58 mm
d2 = 1.58 mm
permittivity = 4.25):
Microstrip Patch Results
North Dakota State University
Separated by a
single anisotropic
layer
(d1 = 1.58 mm
d2 = 1.58 mm
permittivity = 4.25):
Conclusion
North Dakota State University
The coupling between two rectangular microstrip patch antennas in layered anisotropic dielectrics was investigated.
Initially, the E- and H-plane coupling between two microstrip antennas on a single anisotropic substrate was investigated. It is shown that the permittivity in the y-direction (direction
of the optical axis) has the largest impact on the mutual coupling in BOTH the E- and H-planes.
An increase in the permittivity of the substrate in the direction of the optical axis reduces the traditionally stronger E-plane coupling while increasing the traditionally weaker H-plane coupling.
Conclusion
North Dakota State University
Next, the E- and H-plane coupling between two microstrip antennas with a single anisotropic superstrate was investigated. It is shown that the mutual coupling is slightly reduced in
both the E- and H-planes by an increase in permittivity in both directions of the superstrate (i.e., in the direction of the optical axis and in the direction orthogonal to the optical axis).
Finally, the two microstrip antennas were separated by a single anisotropic superstrate and the coupling was investigated. It is shown that both components of the permittivity affect
the mutual coupling in both the E- and H-planes.