Semi Smart Antenna

Islamic University-GazaFaculty of Engineering

Electrical and Computer Engineering

Antenna Theory

PRESENTATIONSemi Smart Antenna using phased dipole

array

Prepared by:

Shadi Y. El-Tanani ( 120041525 )Ali M. Al-Saqqa ( 120040246 )

Instructor:

Dr. Mohammad Ouda

Agenda• Introduction.• Main Idea.• Switching.• Design outline.• Simulations.

Using Matlab Using NEC-Win+ Using PCAAD 5.0

• Final Specification. Using Power Tools

• Conclusion.

Introduction

Semi smart antennas divides the plane into several sectors .

Main Idea

Usually , the Transmission antenna radiation covers all the intended area (cell).

In Semi-Smart systems , an additional antenna array is utilized , it will cover only one sector at a time ,which has the most traffic.

Cont’d

Our application is a transmission tower for cellular systems.

F= 916 ~ 960 MHz we choosed : f= 920MHz

Design Outline

The basic antenna is a an array of 3 dipoles.

Amplitude : λ/2Spacing : λ/4Phase : 0

Cont’d

The semi smart antenna is a scanning The semi smart antenna is a scanning endfire array using 10 elements.endfire array using 10 elements.Amplitude : Amplitude : λλ/2 , Spacing : /2 , Spacing : λλ/4 , Phase /4 , Phase : : ββ

Example :Example :There is a high traffic at sector 3.There is a high traffic at sector 3.sector 3 starts from 45º to 67.5º . sector 3 starts from 45º to 67.5º . Choose Choose θθ=60º ,hence =60º ,hence ββ= -Kd cos = -Kd cos θθ = - = -ππ/4/4

Switching

The switching circuit is based on HPDL-100A

Specifications :Step Size : 10 psMax. Delay Range: 10.23 ns -3.0 dB point @ min.  delay1.26 GHz -3.0 dB point @ max. delay665.0 MHz

Central Base Station

SimulationsUsing MatlabSimulating the semi smart antenna

lamda=input('enter the value of wave length= ');N=input('enter the no. of elements= ');beta=input('enter your progressive phase= ');d=input('enter the seperation distance = ');k=(2*pi/lamda);theta= pi/100:pi/100:2*pi;w=beta+k*d.*cos(theta);AF=sinc(N*(w./2))./sinc(w./2);subplot(2,3,3);polar(theta,AF)

0.2

0.4

0.6

0.8

1

30

210

60

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180 0

β = - kd cosθ ºWe have : θ = 60 ºK d =[2π/λ] * [λ/4] = π/2 Thus , β = - 45º

Using NEC-Win + First , simulating the basic antenna

Azimuth

Elevation

Second , ‘semi-smart’ array θ=60º β=-45º

Elevation azimuth

Azimuth

Elevation

Cont’d θ=30º β=-77.42º

Elevation azimuth

Azimuth

Elevation

Using PCAAD 5.0

Simulating the semi smart antenna when θ=60 º , β=-45º

D = 7.4 DB , HPBW=21.88º

Final Specifications

Since we can’t add our own antennas (dipole), we are restricted to the antennas provided by the software..

The chosen antenna is DB848H35-E whichis a directed dipole antenna with G=

20DBiAnd has the following pattern :

Cont’d - Feeder

Conclusion We have designed a semi smart

transmission tower for cellular GSM .

We faced a lot of problems. For example we didn’t find the equation to calculate the power radiated from the scanning array antenna.

We learned how to BEGIN in designing an antenna application

References

1- C.A. Balanis , ‘Antenna Theory Analysis and Design’ , 3e .

2- Low Cost Scanning Array Antenna , http://

telecom.esa.int/telecom/www/object/index.cfm?fobjectid=14508

3- Microwave and millimeter wave switched-line type phase shifter

http://www.freepatentsonline.com/4616196.html 4- The ARRL Antenna Book; 19th Edition , ARRL