design of a dual band antenna

8/22/2019 Design of a Dual Band Antenna

1/27

Design of a Dual Band Antenna

Guided By: By:

Dr.Abhishek Tomar Akanksha

38737 Archana Rawat38748 Noorie Khan

38773

Vineeta Rani 38810


2/27

OBJECTIVE

This project focuses on the software simulation

of microstrip dual band antenna.


3/27

Review of Antenna

An electrical conductor or system of

conductors

Some important parameters are:-

(a). Gain - measure of the concentration of

radiative power in a particular direction

(b).Efficiency- a measure of the relative power

radiated by the antenna.(c).Effective area - measure of the ability of

the antenna to extract energy from a passing

EM wave.


4/27

(d).Directivity- measure of the concentration of

radiation in the direction of the maximum.

(e).Input Impedence-the impedance presented

by an antenna at its terminals

(f).Radiation Loss - the amount of power that is

lost to the load and does not return as a

reflection(g).Radiation Pattern- plot of the far-field

radiation properties of an antenna as a

function of the spatial co-ordinates


5/27

(h).Beamwidth-the angular separation of the

half-power points of the radiated pattern


6/27

MICROSTRIP ANTENNA

Planar resonant cavities that leak from their

edges and radiate

Consists of a radiating patch on one side of a

dielectric substrate which has a ground planeon the other side

Patch is of conducting material and of any

possible shape.


7/27


8/27

patch radiates from fringing fields around its

edges


9/27

Advantages of Patch Antennas

Light weight and low volume.

Low fabrication cost, hence can be

manufactured in large quantities.

Supports both, linear as well as circular

polarization.

Can be easily integrated with microwave

integrated circuits (MICs).


10/27

Disadvantages of Patch

Antennas

Narrow bandwidth

Low efficiency

Low Gain

Extraneous radiation from feeds and junctions

Poor end fire radiator except tapered slot

antennas

Low power handling capacity.


11/27

Coaxial Feed

common technique used for feeding Microstrip

patch antennas

the inner conductor of the coaxial connector

extends through the dielectric and is solderedto the radiating patch, while the outer

conductor is connected to the ground plane


12/27

main advantage-the feed can be placed at anydesired location inside the patch

major disadvantage-provides narrow

bandwidth and is difficult to model


13/27

Transmission Line Model

Represents the microstrip antenna by two slots

of width W and height h, separated by a

transmission line of length L.

The microstrip is a non homogeneous line oftwo dielectrics


14/27

EQUATIONS USED

reff= (reff+ 1)/2 + (reff- 1)/2[1+12h/W]-1/2

L=0.412h(reff+ 0.3)(W/h + 0.264)/((reff-0.258)(W/h + 0.8))

Leff=L+2 L

Leff=c/(2fo(reff)

W=c/(2fo((r+1)/2))


15/27

Simulation Software IE3D

full-wave electromagnetic simulator

analyzes 3D and multilayer structures of

general shapes


16/27

Proposed Antenna Design

The software part of design is determination of

the radiation pattern and return loss curve

three essential parameters for the design-

1) Frequency of operation (fo)

2) Dielectric constant of the substrate (r)

3) Height of dielectric substrate (h)

a dual band antenna that uses tworectangular patches connected to each other

using 4-briges.


17/27

Parameters used

Permittivity of substrate = 3.18

Height of substrate = 3.400 mm

Frequency =2.4 GHz (due to outer patch)=5.5

GHz (due to inner patch)

Bridge width = 2 mm


18/27

The dimensions of the patch are as follows

Ground plane Lg = Wg = 40 mm (Square

ground plane)

Outer Patch L = W = w2 = 28 mm (Square

outer patch)

Inner Patch L = 18mm

W = 15.13 mm .


19/27

Meshed dual band patch

antenna


20/27

Directivity vs Frequency


21/27

Gain vs Frequency


22/27

VSWR


23/27

RETURN LOSS CURVE


24/27

True 3D Radiation Pattern


25/27

Conclusion


26/27

References


27/27

THANK YOU

design of a dual band antenna

Documents