The Yagi antenna or Yagi-Uda antenna or aerial is a particularly popular form of antenna where directivity and gain are required. Although the Yagi has become. The famous yagi-uda antenna is discussed. The background on yagis (the yagi antenna) are given starting with a discussion of the Japanese inventor Yagi. This example optimizes a 6-element Yagi-Uda antenna for both directivity and input match using a global optimization technique.

Author: Fekree Akikazahn
Country: Mongolia
Language: English (Spanish)
Genre: Music
Published (Last): 24 October 2017
Pages: 24
PDF File Size: 9.80 Mb
ePub File Size: 8.7 Mb
ISBN: 319-6-61586-804-8
Downloads: 12894
Price: Free* [*Free Regsitration Required]
Uploader: Togul

All Examples Functions Apps More. The amplitude and phase of the current that is induced uad the parasitic elements is dependent upon their length and the spacing between them and the dipole or driven element. TV antennas are still a major application of the Yagi antenna. The above graph shows that the gain is increased by about 2.

The passive elements form the reflector and director. The length of the feed element is given in Figure 1 as F. Typically each director will add around 1 dB of gain in the forward direction, although this level reduces as the number of directors increases. The Yagi antenna consists of a single ‘feed’ or ‘driven’ element, typically a dipole or a folded dipole antenna. The waves in the reverse direction interfere destructivelycancelling out, so the signal strength radiated in the reverse direction is small.

Online Calculator Yagi Uda Antenna

Radio frequency antenna types Antennas radio Radio electronics Japanese inventions Amateur radio. A value of dB or lower is considered as a good impedance match.

The ratio of voltage to current at this point is the driving point impedance Z dp of the 2-element Yagi:. Plug and Play Integration.

Branch structures are used to. Yagi anteha the first English-language reference on the antenna in a survey article on short wave research in Japan and it came to be associated with his name.


While the above qualitative explanation is useful for understanding how parasitic elements can enhance the driven elements’ radiation in one direction at the expense of the other, the assumptions used are quite inaccurate. The wave generated by the driven element udx propagates in both the forward and reverse directions as well as other directions, not shown.

Retrieved 11 September Any constraint violations will penalize the objective. Array Antenna, polarization, radiation pattern, stacking distance, UHF antenna, Although the Yagi has become particularly popular for television reception, it is also used in many other applications, both domestic and commercial or professional. The design for the Yagi antenna appears to have been initially developed not by Yagi who was a student, but his Professor Shintaro Uda. If an element is longer than the resonant length, i.

The input reflection coefficient for the optimized Yagi-Uda antenna is computed and plotted relative to the reference impedance of. Although the Yagi antenna is now widely used, it was only in the late s and early s when it started to be used.

Yagi–Uda antenna

Abstract- A Yagi – Uda antenna is one of the most widely used antenna in communication. From Wikipedia, the free encyclopedia.

And now knowing the phase and amplitude of I 2 in relation to I 1 as computed above allows us to determine the radiation pattern gain as a function of direction due to the currents flowing in these two elements. The addition of these waves bottom is increased in the forward direction, but leads to cancellation in the reverse direction. Reflector length 1 variable Director lengths 4 variables Reflector spacing 1 variable Director spacings 4 variables Exciter length 1 variable Exciter spacing 1 variable.


Antena Yagi – Uda: For transmitting much better use of the available power is made because it is possible to focus the transmitted power on areas where it is needed. Japanese intelligence officers did not even recognise that Yagi was a Japanese name in this context. We model element number j as having a feedpoint at the centre with a voltage V j and a current I j flowing into it. The Yagi antenna design has a dipole as the main radiating or driven element to which power is applied directly from a feeder.

Yagi demonstrated a proof of conceptbut the engineering problems proved to be more onerous than conventional systems. Consider a Yagi—Uda consisting of a reflector, driven element and a single director as shown here. Although the name, Yagi is normally used, its full name is the Yagi-Uda antenna. This makes the task of finding the right set of parameters satisfying the optimization goals particularly challenging and requires the use of global optimization techniques.

One must take into account an additional phase delay due to the finite distance between the elements which further delays the phase of the currents in both the directors and reflector s.

The Yagi antenna offers many advantages over other types of antenna in many applications, yet both advantages and disadvantages need atnena be weighed up to ensure the correct type of antenna is chosen for any particular use The director elements those to the right of the feed in Figure 1 will be shorter than resonant, making them capacitive, so that the current leads the voltage.