Week 2 iLab Report
DeVry University
NETW360: Wireless Technologies and Services
ANTENNA TYPES AND COMPUTE RF BEHAVIOR
Submitted to:
Professor
Date: 1/18/14
Antenna Types
Directions: Provide the basic differentiating characteristic of each of the three antenna types listed below. Also provide that typical use of the antenna type.
1. Omnidirectional:
The basic differentiating characteristic of an omnidirectional antenna is that it radiates its signal out equally in all directions depending on the antenna’s orientation. If the antenna is placed vertically the signal will radiate horizontally equally in all directions and if the antenna is placed horizontally the signal ...view middle of the document...
APs using an omnidirectional antenna should be placed in the center of the coverage area. To delve a bit further, the most common type of omnidirectional antenna used for WLANs is a thin, straight metal rod encased in plastic, called a dipole antenna. These diploe antennas are located on APs and are usually hinged so the antenna can be turned 90 degrees in the horizontal position to provide increased coverage vertically, if needed. In addition omnidirectional antennas are used for cellphones, cordless phones, portable radios, and radio broadcasting.
2. Semidirectional:
A semidirectional antenna radiates its signal in one single direction, 180 degrees or less. Semidirectional antennas can also be used indoors and outdoors, but as opposed to omnidirectional antennas, they are not commonly used for indoor WLANs. If a semidirectional antenna is used for indoor purposes it’s generally used for a group of users who are clustered tightly together where a broad coverage area is not needed. In that particular scenario the AP which is housing the semidirectional antenna should be placed in one corner of the room where it can be focused to the clustered group of users. Another way that a semidirectional antenna is different than an omnidirectional antenna in that they can be installed high on a wall and tilted downward toward the coverage area. An omnidirectional antenna cannot do this without causing the signal on the other side of the antenna to be tilted upward.
Semi-directional antennas are used for short to medium distance communications and is commonly used to provide a network bridge between two buildings in a campus environment or down the street from each other. Basically this is a point-to-point configuration in where two buildings are connected via a wireless network. Now that I am thinking about the aspects of a semidirectional antenna, I think that they would work well in facilities with long rows/corridors stacked high like in factories, warehouses, libraries, and hospitals. See these semidirectional antennas can focus their signals down the long corridors.
Although, I know it is not needed for this question, I want to close with the some types of semidirectional antennas which are sectorized, patch, panel, Yagi.
3. Highly-directional:
Highly-directional antennas are different than semidirectional antennas because of their shape, duties, and high gain. They are reflective, parabola shaped devices that cast narrow signal beams very long distances. Whereas semidirectional antennas focus their signal in one direction, but nowhere near as far as a highly directional antenna. The reflector of a highly-directional antenna creates a large surface area that the antenna uses to receive and transmit signals. The shape of the highly-directional antenna allows it to concentrate the signal into a transmitter/receiver that protrudes from the center of the antenna (dish). They have the most focused, narrow beamwidth of...
