3 Element Yagi Antenna Basics | Yagi Antenna calculator
This page covers 3 element Yagi Antenna basics. It mentions Yagi Antenna Calculator and mentions formula used for calculations. The links to other antenna calculators are also mentioned.
The simple Yagi Antenna is shown in the figure-1. It consists of three elements viz. director, dipole and
reflector. It may have one or multiple directors.
Dipole (i.e. Driven Element): It is the feed point where feedline is usually attached from transmitter. This helps in transfer of energy from transmitter module to antenna. The feed point is located at the center of the driven element. It becomes resonant when its electrical length is about half of wavelength of frequency.
Director: It is designed mainly for receiving EM waves. It is shortest of parasitic elements. It has length which is 5% short compare to driven element. It has resonant higher compare to driven element. It helps to achieve desired gain and directional pattern. The spacing between directors usually range from 0.1λ to 0.5λ or more. The Gain of Yagi Antenna depends on length of antenna array and do not depend on number of directors used in the design.
Reflector: It is placed at rear of dipole or driven element. The length is usually 5% more compare to driven element. The spacing of reflector from driven element is about 0.1 λ to 0.25 λ. The spacing also depend on bandwidth, gain, F/B ratio and sidelobe pattern specifications.
The following are the basic specifications considered in selecting Yagi Antenna:
• Front to Back Ratio
Yagi Antenna Calculator
EXAMPLE of 3 element Yagi Antenna:
INPUTS : Operating Frequency (MHz) = 200
OUTPUTS: Reflector Length = 0.7425 meters, Dipole Length = 0.7095 meters, Director Length = 0.66 meters
Reflector to Dipole Spacing = 0.1875 meters, Dipole to Director Spacing = 0.1875 meters
Formula/Equations used in Yagi Antenna Calculator
Following formula/equations are used in the Yagi Antenna Calculator.
This 3-element Yagi Antenna calculator is useful to design the Yagi Antenna.