5029200000TECHNOLOGICAL UNIVERSITY OF THE PHILIPPINES
COLLEGE OF ENGINEERING
ELECTRONICS ENGINEERING DEPARTMENT
Combination of Yagi-Uda and Folded Dipole
Alvarez, Adrian D.
Munda, John David C.
Reyes, Ricca May Q.
Rivo, Keenan Dave D.
Torrejos, Rayn Louise M.
Ventura, Camille H.
Submitted to:Engr. Cherry G. Pascion
Combination of Yagi-Uda and Folded Dipole Antenna
Adrian ALVAREZ, John David MUNDA, Allyssa OCAMPO, Ricca May REYES, Keenan Dave RIVO, Rayn Louise TORREJOS, Camille VENTURA
The goal of this project is to design and construct a model of an antenna that can be utilized to skim 80% of Metro Manila, Philippines’ local channels. The students chose to combine Yagi-Uda and Folded Dipole antenna. Table 1.1 presents these channels.
Table 1.1. Television Channels in Metro Manila Philippines
Frequency range in MHz TV Station Channel
VHF 54 – 60 ABS-CBN 2
66 – 72 PTV 4
76 – 82 ABC 5
174 – 180 GMA 7
186 – 192 RPN 9
198 – 204 QTV 11
210 – 216 IBC 13
UHF 512 – 518 SBN 21
524 – 530 STUDIO 23
572 – 578 BEAM 31
608 – 614 UNTV 37
620 – 626 SMNI 39
656 – 662 AKSYON TV 41
674 – 680 INC-TV 48
The Yagi antenna often called the Yagi-Uda RF antenna is commonly used where directivity and gain are essential in designing an RF antenna. The Yagi has become common for television reception, but it is also used in various commercial and domestic applications where an RF antenna is required that has directivity and gain.
The Yagi antenna originates its name from its two Japanese inventors Hidetsugu Yagi and Shintaro Uda. In 1928, the RF antenna design idea was first drawn in a paper that Yagi presented. Then, its use has grown rapidly to the point where today a television antenna is the same with an RF antenna having a central boom with lots of elements involved. (Yagi Antenna/Yagi-Uda Antenna, n.d.)
Folded Dipole Antenna
The folded dipole antenna for FM broadcasting was developed by Aram in 1946. It is composed of a basic dipole with two ends connected by an additional conductor. It is called folded dipole antenna since the ends seem to be folded back.
This antenna is preferred because it serves as a driven element of the Yagi-uda antenna CITATION Sar06 l 1033 (Sarkar, Mailloux, Oliner, Salazar-Palma, ; Sengupta, 2006).
III. Design Considerations
For the Dipoles :
f = 213MHz
f = 555MHz
f = 677 MHz
For the Yagi uda:
f = 555MHz
Table 3.1.a. Element Length Computation
Element Formula Length (mm)
Reflector ?/2 D1 ?/2-.5(?/2) D2 D1-.5(D1) D3 D2-.5(D2) Table 3.1.b. Element Distance Computation
Distance Formula Distance (mm)
D-R 0.2 ? D-D 0.125 ? The previous tables show the computed values for the lengths and distances of the elements of the antenna. These data would be used to construct the actual antenna.
The physical design and structure of the antenna depends on the frequency considerations. The students have come up with the following design for the antenna.
For the Dipoles:
The formula used is:
Length in inches = 468fMHz(12)1st Dipole:
L = 468213(12)L = 26.36 in.
L = 468555(12)L = 10.12 in.
31849319889L = 468677(12)L = 8.3 in.
For the Yagi uda:
The formula used is:
Length in inches = (12)*(0.440)* ?
Length of directors:
L = (12)*(0.125)*( 3×108555MHz)
L = 9.363 in.
Spacing from Driven Element:
The Formula used is:
Length in inches = (12)*(0.125)* ?
L = (12)*(0.125)* ( 3×108555MHz)
L = 2.85 in.
Figure 3.2. Physical Design of Antenna
The table presents the over-all cost for the construction of the antenna.
Quantity Type Price Total
1 Balun 25 25
1 Coaxial cable 150 150
1 Antenna 250 250
1 2-m dipole stick 100 100
1 Female-female coax connector 50 50
1 Lightning Arrester 50 50
10 Rubber cap/cover – –
Grand total Table 3.1.c. Cost of Antenna Construction
IV. Results and Discussion
285751490980With the combination of both the Yagi-Uda and folded dipole, we can see an effective antenna. The following figure shows the channels received using the constructed antenna. A total of 12 channels were received, which surpassed the target quota of 80% of the total channels in Metro Manila.
Table 4.1. Channels Received by the Antenna
The resulting video needs improvement. However, the audio received by the antenna were good in terms of quality and audibility.
In this project, theoretical computations for the antenna parameters are proven true with the corresponding results.A combination of a Yagi-Uda and folded dipole antenna is an effective and low-cost antenna that can receive more than 80% of the total channels in Metro Manila. This was also based on the modification of a practical classic Yagi Uda antenna.
Our group would like to express our deepest gratitude to those who has given us the resources and time to accomplish this project. We have come to appreciate deeply our project supervisor and guide, Prof. Cherry G. Pascion, who has given us her suggestions and advice in the completion of this project.
Yagi Antenna / Yagi-Uda Antenna. (n.d.). Retrieved September 29, 2018, from https://www.radio-electronics.com/info/antennas/yagi/yagi.php
Sarkar, T. K., Mailloux, R., Oliner, A. A., Salazar-Palma, M., ; Sengupta, D. L. (2006). History of Wireless. John Wiley ; Sons.
Television Frequency Table. (n.d.). Retrieved September 29, 2018, from http://www.csgnetwork.com/tvfreqtable.html