How is electrical antenna length calculated?

How is electrical antenna length calculated?

To calculate the electrical length of the line you need to multiply the velocity factor of the line (available from the supplier of the line) by the free space length. For the length in feet, this is (983.6 / frequency in MHz) * velocity. For the length in meters, this is (299.8 / frequency in MHz) * velocity.

What is antenna voltage?

As the electric field (V/m) hits the antenna it impresses a voltage along its length (m*V/m = V) relative to ground. The receiver detects the voltage between the antenna and ground. Another way to think of this type of antenna is as one lead of a voltmeter measuring the potential in space.

What is antenna size unit?

Antenna directivity is the ratio of maximum radiation intensity (power per unit surface) radiated by the antenna in the maximum direction divided by the intensity radiated by a hypothetical isotropic antenna radiating the same total power as that antenna.

What is electrical antenna?

An antenna is a device used to transmit or receive radio waves, which are electromagnetic waves with wavelengths longer than that of infrared light. Antennas mediate between electrical signals flowing in a wire or waveguide and electromagnetic waves moving through air, water, a vacuum, or some other medium.

Is an antenna a circuit?

Thus, antennas have capacitance and inductance. They also have resistive losses (unless they are made of superconductors) and radiation resistance. Putting all these together, antennas can be modeled as an RLC circuit.

Why is antenna size half the wavelength?

Since the speed of light in a vacuum or air is very close to the speed of light in an antenna (~80\%), the length of the antenna will be close to the wavelength of the EM wave. In fact, most simple antennas have a length close to half the wavelength of the signal they are built to receive.