rudra pratap singh-microstrip antenna

7/31/2019 Rudra Pratap Singh-Microstrip Antenna

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In its most fundamental form, a Microstrip Patch antenna

consists of a radiating patch on one side of a dielectric

substrate which has a ground plane on the other side. In order to simplify analysis and performance prediction, the

patch is generally square, rectangular, circular, triangular, and

elliptical or some other common shape.

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Waves in microstrip patch antenna

1. Surface waves

2. Leaky waves

3. Guided waves


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1. Surface waves

2. Leaky waves


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Feed techniques

Feed techniques

Contacting Feed Non contacting feed

Microstrip feed

Coaxial feed

Aperture-coupled feed

Proximity-coupled feed


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1. Contacting feed

(a). Microstrip feed

(b). Coaxial feed


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2. Non contacting feed

(a). Aperture coupled feed

(b). Proximity coupled feed


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Low profile (can even be conformal)

Easy to fabricate(use etching and phototlithography)

Easy to feed(coaxiale cable, microstrip line etc.)

Easy to use in array or incorporate with other

microstrip circuit elements.

Patterns are somewhat hemispherical with a

moderate directivity(about 6-8 dB typical)

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Low bandwidth( but can be improved by a variety of

techniques). Bandwidth of a few percent are typical.

Efficiency may be lower than other antennas.Efficiency is limited by conductor and dielectric

losses, and by surface-wave loss.

Low gain.

Extraneous radiation from feeds and junctions.

Poor end fire radiator except tapered slot antennas.

Low power handling capacity.

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Directivity:

In view of the cavity model, the

simplified expression for directivity D can be written

as-

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Gain:

Gain of the patch antenna from the directivity

relative to the vertical axis is normally 2 dB.

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Bandwidth:

Bandwidth is related as-

where, S= voltage standing ratio,

Q0= unloaded radiation quality factor.

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Efficiency:

where, = efficiency,

Pr= radiated power,

Pt=power dissipated due to conductor loss,

Pd= power dissipated due to dielectric.

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Applications:

Microstrip antennas are increasingly gaining popularity

for use in wireless application due to their low profile

structure.

Some applications of microstrip patch antenna are

tabled as below-

Cellular phone & video

Collision avoidance radar

Direct broadcast satellite

Global positioning satellite

GSM & Paging

Personal communication system

Wide area computer networks

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rudra pratap singh-microstrip antenna

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