mutual coupling between coax-fed rectangular microstrip ...braaten/aps_2010.pdfmutual coupling...

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

Problem DefinitionConsider:


Optical axis is in the y-

direction.

Interests and Background


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


Consider:

L = 6.55 cm,

W = 10.57 cm,

d1 = d2 = 1.58 cm

f = 1.41 GHz.



xd = 16.8 mm

zd = 52.85 mm

f = 1.41 GHz

Permittivity = 4.25

(chosen by isolating the patch)



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.



A single grounded

anisotropic

substrate

(d1 = 1.58 mm and

d2 = 0 mm.):



A single

anisotropic

cover

(d1 = 1.58 mm

d2 = 1.58 mm

permittivity = 4.25):



Separated by a

single anisotropic

layer

(d1 = 1.58 mm

d2 = 1.58 mm

permittivity = 4.25):

Conclusion


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


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.

Questions

Thank you for listening!


mutual coupling between coax-fed rectangular microstrip ...braaten/aps_2010.pdfmutual coupling...

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