Yagi antennas are also known as Yagi-Uda antennas. They were named after two inventors who were both Japanese nationals. The technology behind these antennas has found practical application in ham radio and TV reception. It can also serve as a bridge antenna, linking a site to a particular access point on WiFi.
As a driven element, the Yagi system of the antenna comes with a dipole. Normally, the “reflector” can be found behind the driven element and may add the forward gain of around 4dB to 5dB. However, it must be noted that not all Yagi system of antenna comes with or is bundled with a reflector. Should the antenna come with extra directors, it will get an average gain of 1dB.
If they don’t radiate signal, parasitic elements can be added to the main element. This measure will help a lot in altering its performance for the better. The signal amplitude and phase will directly depend upon the parasitic element’s size and spacing with respect to the driven element.
So, what could be the possible advantages of yagi antennas? Can we anticipate any kind of disadvantage from these types of antenna? When is the best time to utilize a Yagi system of antenna?
Yagi Antennas Advantages
When it comes to antennas, we qualify Yagis as somewhat directional. Yagi-uda antennas usually come with a beamwidth of about 50° to 70°. They tend to produce high gain with omnidirectional antennas since they have a natural tendency to focus their input only in one direction. Hence, this explains the reason why they are best to have when it comes to obtaining or receiving signals of lower strength.
The high gain attribute of the Yagi system antenna is working to their advantage in the sense that it is giving them a good range. With respect to their physical size, they tend to have the most gain as opposed to other antennas such as a log-periodic type.
The design for this antenna works in such a way that it effectively filters out signal noise, originating from a completely different or opposite direction. This is the underlying reason why the Yagi system antenna is the right choice to use for high demand applications. A typical example of this is telecommunications.
Yagi system antennas are much easier to aim as opposed to some arrays. The manner in which they are formed and constructed makes it easy for them to get mounted on vertical towers or any other available structure there is.
Normally, Yagi antennas come with a cheaper tag price than their counterpart LP antenna and this is due to the fact that they are simpler when placed side by side with antennas of periodic log type.
Yagi circuit boards can be built, with the use of printed circuit boards, even just by the use of simple rods. Just make it sure though that you have them positioned properly.
Our Collective Observation on Yagi-type of Antenna
You can tell from the manner in which this type of antenna is designed so that they are made for balance, but there are instances this can get disrupted, too. This is likely to occur if you place a balun at the feed joint line, that point where the drive element gets connected.
With respect to the driven element’s design, it can bring about balance or imbalance. Keep in mind that cheap or reasonably priced Yagis are balanced. This eliminates the need for the balun.
If elements will be added to a Yagi type of antenna, it’s a tendency now to increase its directionality. Its focus becomes narrower, but will likely receive a better signal from that particular direction since there is a dramatic improvement in the signal to ratio.
In simple terms, there is a significant reduction on the interference levels, most especially coming from the sides.