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LOG PERIODIC ANTENNA
Most families in Kenya have T.V receiver due to the fact that most of their antennas do not receive required signal clearer in every family there is a member who always pulls lifts, lowers turns the antenna as he/she tries to get clearer picture. Usually their results are not worth the efforts.
|language || ||english
|wordcount || ||7464 (cca 21 pages)
|contextual quality || ||N/A
|language level || ||N/A
|price || ||free
|sources || ||3
Table of contents
Scope and limitation 1
Study of electromagnetic waves and electromagnetic 1
Electromagnetic wave 2
Properties of electromagnetic waves 2
Electromagnetic spectrum and radio spectrum 3
Electromagnetic spectrum 4
Antenna operation 4
How antenna radiates 5
Antenna performance and associated parameters 7
Types of polarizations 7
Application of polarization 8
Antenna gain 8
Radiation pattern and beam width 9
Input impedance 11
Voltage standing wave ratio (vswr) 11
Return loss (rl) 12
Antenna efficiency 12
CHAPTER II (TWO).
Log- periodic concept and design 13
Brief history of log periodic 13
Log-periodic concept 13
Log –periodic operation 14
Basic design theory equations 14
Design procedure 17
Log periodic antenna design for uhf TV band 19
Input feeding 20
Antenna fabrication (materials) 21
Test and measurements 22
How to obtain gain 24
Preview of the essay: LOG PERIODIC ANTENNA
INTRODUCTION THE NEED Most families in Kenya have T.V receiver due to the fact that most of their antennas do not receive required signal clearer in every family there is a member who always pulls lifts, lowers turns the antenna as he/she tries to get clearer picture. Usually their results are not worth the efforts. If these people will adopt log-periodic antenna their problem will have been iron out and their Television will never be same again. OBJECTIVES The objective of this research is to design, construct, and test operation of an antenna that receives UHF T.V signal. SPECIFICATIONS Bandwidth (0.3 Ghz-3Ghz) Standing wave ratio (1.8-1) Directivity 9.5dB Gain 7.4dB over half wave dipole (1/2) SCOPE AND LIMITATION SCOPE My research will include:- ϕ Study of electromagnetic waves ϕ Antenna fundamentals ϕ Antenna performance parameters ϕ Antenna measurements ϕ Log- periodic antenna design and Assembly LIMITATIONS. The antenna design is based on UHF band only that is (0.3 GHz to 3 GHz) considering the design procedures of a log periodic antenna. The limitation of the study arises from the fact that most Kenyan TV broadcast companies uses the UHF band for the transmission ...
... is given by: -(Power gain) G1= W2/W1 Factors that may produce error in measurement. • Receiving and transmitting antennas are too close together and thus are not in the far zone. • Reflection from the ground and nearby objects interferes with direct radiation. MEASUREMENT PERFORMED. After design and construction the antenna should be tested to see its performance compared with existing antennas in the market. The reference aerial is the existing market aerial both aerials are located in constant field strength. The T.V receiver is first connected to the reference aerial and output signal is measured in terms of picture Quality an then T.V receiver is connected to the LPDA (antenna under test) and the output of the receiver is measured. The two results are compared.
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