semi smart antenna
TRANSCRIPT
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)
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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