How does antenna gain work

Additionally, a high gain antenna will not reach users sat down as the wireless signal is projected better horizontally rather than vertically. The lower dBi antenna will provide more of a round shaped signal pattern, which will then project the WiFi signal lower to the ground with better vertical reach, as illustrated in the diagram below.

You may want to take some manufacturers' published gain figures with a pinch of salt, as figures can often published with the highest possible gain, in an ideal environment for the antenna. Even omnidirectional antennas can potentially have their 'blind spots' or 'nulls' in radiation patterns. Understanding the radiation pattern of an antenna can be a great way to identify important parameters, like the beam width of an antenna.

Moreover, you can be looking at two different antennas that have the same gain according to the spec sheets, but one of them can have the potential to perform better than the other.

An understanding of where and how the antenna will be deployed is key to help determine which environmental parameters are important and in turn which antenna would suit you best. Some antenna manufacturers, such as Ubiquiti and Poynting, publish their Radiation patterns. This insight will give you the confidence to choose which antenna is best for your application. We would recommend that you look at the gain across the required frequency band s and not just the published maximum gain, because antenna radiation patterns and gain change as the frequency changes.

Another thing that you have to be aware of is that walls or objects can weaken the signal. In addition, certain radios work better transmitting more power and using smaller antenna while others like to transmit less power but use larger antenna.

Having a bigger antenna does not always increase usability of the signal. It may increase the total signal strength but it also can increase the noise in the signal. Example Gain Pattern for an Antenna. However, more often a single number is quoted the gain is the 'peak gain' over all directions.

Antenna Gain G can be related to directivity D and antenna efficiency by: [Equation 1] The gain of a real antenna can be as high as dB for very large dish antennas although this is rare. Directivity can be as low as 1.

However, the peak gain of an antenna can be arbitrarily low because of losses or low efficiency. Electrically small antennas small relative to the wavelength of the frequency that the antenna operates at can be very inefficient, with antenna gains lower than dB even without accounting for impedance mismatch loss. Is a High Gain Antenna Advantageous? Often manufacturers of antennas be they wifi antennas, gps antennas, or tv antennas specify the antenna gain.

For instance, manufacturers of wifi antennas may market the wifi antenna as a "high gain antenna", which is more expensive than a similar low gain antenna. The question is: do we want high gain? The answer is: it depends. If you know exactly where your desired signal is coming from, you would like to have maximum gain towards the desired direction.

However, if you don't know where the desired signal will be coming from, it is better to have a low gain antenna. A couple examples will make this clear. As you can see in the illustration, using a gain antenna may cause poor performance in a hilly environment. Mobile antenna choice has a lot to do with the physical terrain.

On an open and flat highway, a high gain antenna will be better…3 dB, 6 dB, etc. The other type of gain is directional and is important for base stations. When you turn the bezel of a flashlight you are not increasing the power, you are focusing the light and making the energy denser in that area.

In RF, for every 3db of gain you double the power. In the world of antennas, you do not double the output, you double the density of signal level in a given area.