DIRECTIONAL VS OMNIDIRECTIONAL ANTENNAS

Posted by on Jun 10, 2014 in Articles | Comments Off on DIRECTIONAL VS OMNIDIRECTIONAL ANTENNAS

DIRECTIONAL VS OMNIDIRECTIONAL ANTENNAS

Directional antennas cover signals in a specific direction. The antennas must be directed towards the direction of the signal receiver or transmitter in a Wi-Fi hotspot or router. The user should know the width of his or her directional antenna’s reception cone in order to get signals or greater quality and strength.

Omni directional antennas are utilized in the creation of hot spots by sending signals over a big area in all directions or by receiving the signals from any direction when the location of the transmitter is unknown. Omni directional antennas have radiation cones that transmit at angles of 360 degrees.

Antennas give wireless systems three essential properties that include direction, gain and polarization. Gain is a measure of the increase in energy or power that an antenna appends to a radio frequency signal. Direction is the transmission pattern’s shape. Polarization is the physical alignment of the element in an antenna that emits the radio frequency energy.

Interference Interference in wireless networks comes from sources such as cordless phones, microwave ovens, radar signals from airports and other similar devices that utilize the same frequency band.

Even though directional antennas normally focus the energy in a specified direction which can help to overcome multipath and fading, multipath on itself lowers the focusing power of a rp-sma antenna. Directional antennas utilized in indoor applications have a lower gain, lower front to side lobe ratio and a lower front to back lobe ratio. This leads in a lower ability to reduce or reject interference signals experienced from areas outside the lobe area.

Merits and demerits of Omni directional antennas

Installation of Omni directional antennas is so easy. You can install them in an upside down position from a ceiling in an indoor environment due to its 360 degrees horizontal pattern. You can also attach the antenna easily to the access point devices due to their simple shape.

Omni directional antennas are vertically polarized implying that you cannot utilize cross polarization to eliminate interference while using the antennas.

Merits and demerits of directional antennas

With a directional antenna, you can always direct the radio frequency energy in a single direction in order to increase operation distances. This implies that the beamwidth will decrease while the range will increase.

The major demerit of directional antennas is that they are unable to cover larger areas. This disadvantage is experienced more in an indoor environment where larger angles should be covered around the access point.

Mounting of directional antennas is also a difficult affair. This is so because the antenna arrays should always direct to the desired area of coverage.

Conclusion Utilizing directional antennas for certain indoor applications can be of great value but the majority of installations use Omni directional antennas because of their advantages as sited in the article. To determine the best antenna for your wireless network, you should make sure that you undertake a proper site survey. Perhaps you can erect two or more different types of antennas in your network and switch between them using coaxial switches to ensure that you maximize on the benefits of both the directional and Omni directional antenna.