Antenna Types

Question 1

Omnidirectional Antenna / Rubber Duck Antenna ?

Answer 1

Omnidirectional antennas radiate RF signal in all directions Small, rubber-
coated dipole antenna, often referred to as a rubber duck antenna. The default antenna of many access points.

Question 2

Semi-directional Antenna ?

Answer 2

Semi-directional antennas are designed to direct a signal in a specific direction.

Question 3

Where is semi direction antenna Used ?

Answer 3

Used for short to medium distance communications

Question 4

Types of Semi directional Antenna ?

Answer 4

Patch
Planer
Yagi

Question 5

Patch Antenna ?

Answer 5

Used for outdoor point-to-point communications up to about a mile. More commonly used as a central device to provide unidirectional coverage from the access point to the clients in an indoor environment.

Question 6

Planar Antenna ?

Answer 6

Planar antennas are also often used to provide coverage for long hallways with offices on each side

Question 7

Yagi Antenna ?

Answer 7

They are typically used for short to medium distance point-to-point communications of up to about 2 miles, although high-gain Yagi antennas can be used for longer distances

Question 8

Highly Directional Antenna ?

Answer 8

Highly directional antennas are strictly used for point-to-point communications, typically to provide network bridging between two buildings. They provide the most focused, narrow beamwidth

Question 9

Types of Highly Directional Antenna ?

Answer 9

Parabolic Dish Antenna

Grid Antenna

Question 10

Parabolic Dish Antenna ?

Answer 10

The parabolic dish antenna is similar in appearance to the small digital satellite TV antennas that can be seen on the roofs of many houses

Question 11

Grid Antenna ?

Answer 11

The spacing of the wires on a grid antenna is determined by the wavelength of the frequencies that the antenna is designed for.

Question 12

Antenna Array ?

Answer 12

A group of two or more antennas that are integrated together to provide coverage.

Question 13

Beamforming ?

Answer 13

Beamforming is a method of concentrating RF energy. Concentrating a signal means that the power of the signal will be greater and the SNR at the receiver should therefore also be greater, providing a better transmission

Question 14

Types of Beamforming?

Answer 14

Static
Dynamic
Transit

Question 15

Static Beamforming?

Answer 15

Performed by using directional antennas to provide a fixed radiation pattern. Static beamforming uses multiple directional antennas, all clustered together but aimed away from a center point or location.

Question 16

Dynamic Beamforming

Answer 16

Dynamic beamforming focuses the RF energy in a specific direction and in a particular shape. Like static beamforming, the direction and shape of the signal is focused. The radiation pattern of the signal can change on a frame-by-frame basis.

Question 17

Transit Beamforming?

Answer 17

Transmit beamforming (TxBF) is performed by transmitting multiple phase-shifted signals with the hope and intention that they will arrive in-phase at the location where the transmitter believes that the receiver is located.

Question 18

Antenna Polarization?

Answer 18

As waves radiate from an antenna, the amplitude of the waves can oscillate either vertically or horizontally It is important to have the polarization of the transmitting and
receiving antennas oriented the same in order to receive the strongest possible signal.

Polarization is not as important for indoor communications because the polarization of the RF signal often changes when it is reflected, which is a common occurrence indoors

Question 19

Antenna Diversity?

Answer 19

Antenna diversity exists when an access point has two or more antennas with a receiver functioning together to minimize the negative effects of multipath.

Question 20

Switched Antenna Diversity ?

Answer 20

When the access point senses an RF signal, it compares the signal that it is receiving on both antennas and uses whichever antenna has the higher signal strength to receive the frame of data. This sampling is performed on a frame-by-frame basis, choosing whichever antenna has the higher signal strength.

Question 21

In which Standard Switched Antennas diversity is used ?

Answer 21

In 802.11n Standard

Question 22

Multiple input and Multiple Output (MIMO)

Answer 22

Wireless radio architecture that can receive or transmit using multiple antennas concurrently. These techniques send data by using multiple simultaneous RF signals, and the receiver then reconstructs the data from those signals.

Question 23

Which Standard Use MIMO?

Answer 23

802.11n and 802.11ac

Question 24

Beamwidth ?

Answer 24

Measurement of how broad or narrow the focus of an antenna. Measured both horizontally and vertically from the center
or strongest point, of the antenna signal to each of the points along the horizontal and vertical axes where the signal decreases by half power.

Question 25

Azimuth Chart ?

Answer 25

H-Plane (Top-Down View)

Question 26

Elevation Chart ?

Answer 26

E-Plane (Side View)