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8/14/2019 En Micro Strip Anteena
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Compact Microstrip Antenna
By
Danish Kumar Hotta
Roll No: EC 200117169
Under the guidance of
Mr. Rowdra Ghatak
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Introduction
The microstrip antenna is a very thin metallic strip,
placed a small fraction of a wavelength above a
ground plane, separated by a dielectric.
Where size, weight, cost, performance, ease of
installation, are of primary concern, microstrip
antennas are the best solutions.
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Construction and Geometry
2.2 < r < 12. Low dielectric=>better efficiency, larger B/W. A microstrip patch antenna is a radiating patch on one side of
a dielectric substrate, which has a ground plane on the
underside. The EM waves fringe off the top patch into the
substrate, reflecting off the ground plane and radiates out intothe air.
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Types of Microstrip antennas
a) Single radiating patches
Square, rectangular, dipole, circular, elliptical,
triangular, etc.
b) Single slot radiator
Narrow slot, circular ring slot, wide slot, circularpatch slot.
c) Microstrip traveling wave antennas
Comb, meander line type, rectangular loop type,
Franklin type MTWA.d) Microstrip antenna arrays
Consists of series of antennas connected with each
other to give better performance.
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Feeding methodsa) Microstrip feed
Easy to fabricate, simple to match by controlling the inset
position and relatively simple to model.
b) Coaxial probe feed
Easy to fabricate, low spurious radiation; difficult to
model accurately; narrow bandwidth of impedancematching.
c) Aperture coupling (no contact), microstrip feed line and
radiating patch are on both sides of the ground plane, the
coupling aperture is in ground plane
Low spurious radiation, easy to model; difficult to match,narrow bandwidth.
d) Proximity coupling (no contact), microstrip feed line and
radiating patch are on the same side of the ground plane
Largest bandwidth (up to 13%).
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Criteria for substrate selection
a) Possibility for surface-wave excitation
b) Effects of dispersion on the dielectric constant and low
tangent of the substrate
c) Magnitude of copper loss and dielectric lossd) Anisotropy in the substrate
e) Effects of temperature, humidity, and aging
f) Mechanical requirements: conformability, machinability,
solderability, weight, elasticity, etc.g) Cost
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Polarization types
Linear polarization
Circular polarization
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Bandwidth consideration
Narrowband Vs. Broadband Bandwidth measurement
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Design methodology
Research
Determining substrate Permittivity
Bench mark with commercially available antenna
Design feed impedance
Investigate broad band techniques
Design the broadband patch
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Some important structures
Rectangular patch
Transmission model
Cavity model
Circular patch
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
Conclusion
Disadvantages: Relatively low efficiency (due to dielectric
and conductor losses) Low power
Spurious feed radiation (surface waves,strips, etc) Narrow frequency bandwidth (at most a
couple of percent) Relatively high level of cross polarization
radiation Applications:
Radio and wireless communications, aircrafts,
spacecraft and missile.
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Technical Seminar Presentation-2004
Presented By: Danish Kumar Hotta [EC200117169]
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