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How to Calculate Radiation Patterns

Antennas help convert the electromagnetic radiation from in the free space into a guided wave in a transmission line. When a signal is fed into an antenna, it distributes the signals into space in a specific pattern. The radiation pattern of an antenna is the strength of the radiations in various directions from the antenna at a constant distance. The patterns can be omnidirectional or highly focused. This three-dimensional pattern emitted by the antenna is one of the most important factors for the proper functioning of a communication system. It can, however, be manipulated to suit the needs of the project. Calculating the radiation pattern of the antenna is often the first step in designing the antenna and its communication system.

Things You'll Need

12-volt battery
Antenna
Transmitter
450-megahertz receiver
Coaxial cable
Computer with Matlab

Instructions

- 1
  Connect a radio receiver to a 12-volt battery. Connect your antenna to the female jack on the back of the receiver and turn on the receiver. Select the FM mode on the receiver, and enter the frequency using the numeric pad on the upper-right corner of the receiver.
- 2
  Connect the radio transmitter to the coaxial cable from the antenna, and connect the antenna to the 12-volt battery. The LED power indicator of the transmitter should light up.
- 3
  Connect an AC/DC power inverter to the battery, and flip the switch on the transmitter to start transmitting the signals.
- 4
  Record the measurements on the signal meter of the receiver. The values are measured in terms of the attenuation factor and are represented as decibles or dB. Repeat the measurements by transmitting the waves at different angles. Plot the data on a graph or enter the data into the Matlab software to plot the data and determine the pattern automatically.

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