Project Presentation on

Designing of Microstrip Antenna

For RFID

OUTLINE • What is MICROSTRIP ANTENNA?• Microstrip antenna structure• Feed technique• What is RFID• RFID implementation • Design of microstrip• Results• Bibliography

What is Microstrip antenna?

Microstrip antenna is a metallic patch printed on a thin ,grounded dielectric substrate .

Feed with coaxial line or coplanar microstrip line.

It radiates a broad beam broadside to the plane of the substrate.

After the original configuration was proposed, dozens of variations in patch shape, feeding techniques, substrate confg. and array geometries have been developed.

Basic Structure

Consists of a radiating patch of metal usually a copper conductor (thickness t<<λo)

A dielectric substrate (of thickness h<<λo and dielectric constant Єr)

A microstrip feed line is generally used to excite the patch antenna.

Microstrip antenna

Parameter affecting antenna

Patch Geometry

Substrate property

Feed technique

Patch Geometry

Square Rectangular Dipole Circular

Elliptical Ring Sector Triangular

Dielectric Substrate A dielectric substrate with properties such as low

loss, low dielectric, and sufficiently thick substrate can provide maximum radiation efficiency and bandwidth.

However, the antenna dimensions are large when low dielectric substrates are used.

Low loss substrates provide good radiation efficiency.

But also make the microstrip antenna a high-Q device, resulting in narrow bandwidth.

high dielectric substrates , higher loss , reduced performance.

Feed Techniques Classified on two broad categories:-

Directly connected to patch. Eg:-microstrip line, coaxial line.

microstrip line coaxial line

Coupled to the patch. Eg:- aperture coupling and proximity.

aperture coupling proximity coupling.

What is RFID?

Radio Frequency Identification Device.

RFID is an automatic identification method.

It stores and remotely retrieves data from RFID tag/transponders.

RFID system block representation

Implementation

Implementation of RFID The reader is connected to host computer. It programs the reader & store information

received from the transponder. Transponder is placed on the object to be

identified. Reader is radio transceiver connected to

antennas. The tag consists of an antenna & the RFID IC

that contains data.

Classification of RFID

Based on tags• Active tags• Passive tags

Based on frequency• LFID (30–300 kHz) • HFID (3-30 MHz)• UHFID (300 MHz-3 GHz)

Why Microstrip antenna in RFID?

Easily mountable.

Structurally robust and light weight.

“Metal -water “problem in dipoles.

Designing of antenna

It is possible to design the rectangular microstrip antenna using the following equations with the aid of the software package SONNET LITE -11.55

Select the substrate material of relative permittivity

Єr=2.45 Taconic TLX0 Dielectric height (h) h<<λo ,taken to be

0.787mm (apprx.) Metallization thickness of 0.2mm (copper) Calculation of the practical width of the

microstrip patch conductor

Calculation of the practical length width of the microstrip patch conductor width by:

Substituting values of εeff and ΔL in formulae of L ,Calculate L Cell size should be < λo/20 .

Using sonnet we simulate the design of antenna done on the calculated dimensions and specifications

Finally we got the response graph of frequency and negative return loss in dB.

TXLINE Calculator

PARAMETER CALCULATED

Parameters Values

Length of antenna patch

39.15mm

Width of antenna patch

46.99mm

Thickness of patch 0.2mm

Dielectric material Taconic-TLX0

Dielectric constant of substrate

2.45

Width of substrate 0.787mm

Cell size 2 × 1.5 mm

ANTENNA STRUCTURE

PATCH

MATCHING

DEVICE

MICROSTRIP LINE

RESULT

SMITH CHART

Bibliography

RFID transponder by Stevan Preradovic,Nemai C. Karmakar, Issac Balbin.

Novel microstrip antenna on RFID by Madhuri Eunni.

Notes on microstrip antenna by Sanjeev Gupta.

Microstrip anteena by D.M.Pozar

THANK YOU…

FOR ANY QUERIES… YOU ARE WELCOMED..