What is Antenna?
Simply speaking, Antenna is a device which converts electrical signals to EM waves or vice versa. In the case of a transmitting antenna, the electrical signal from the transmitting circuit is converted to EM waves and is radiated into the atmosphere. In the case of a receiving antenna, the EM waves in the atmosphere is captured and is converted back to electrical signals for further processing. The dimensions of various parts of antenna depends up on the frequency of the EM waves that are being transmitted. The dimensions of components of the antennas will vary to match the frequency or wavelength of the signal to be transmitted.
Types of Wireless Antenna
Omni directional antennas– The Wireless Antennas belonging to this type equally distribute the signals in a 360o pattern. This enables a wider coverage for both indoor and outdoor wireless systems. The router for our Wi-Fi at home usually has a Rubber Duck Antenna which is a sub-type of Omni directional antennas. It is attached in a flexible manner so that it can be rotated vertically and horizontally to achieve the best signals. In some routers, the antenna is internally set and not visible outside.
Directional Antennas- As the name suggests, these antennas are made in a way to concentrate the signals in a single direction. In most cases, a narrower range of signal results in consolidation of energy. This, in turn, implies a higher gain and therefore greater strength. Directional antennas are very good for point-to-point wireless connections. The most common types under Directional Antennas are Yagi, Dish, Horn and Patch.
One cannot compare these two types of Wireless Antennas because they work with distinct mechanisms and have different applications. Their usefulness and performance should be reviewed individually. Also, there are many other factors such as placing, environmental conditions and obstructions around that can affect the efficiency of a Wireless Antenna.