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When a net current flows from point A to point B (i.e. there is a net flow of electrons induced by a potential difference), the net movement of the electrons creates an electromagnetic field which can be described by the set of vector equations published by James Maxwell in 1873.

In the simplest case imagine a coil of wire. Pass a current through the coil, a magnetic field is induced and metal objects can be picked up. The reverse is also true, move a magnet through the coil and a voltage (electric field) is induced causing a current to flow through the coil. Hence electric fields and magnetic fields are interrelated, one causes the other and vice versa. In fact an electric field in direction x causes a magnetic field at 90 degrees to it in direction y.

When a sinusoidal alternating current is passed along a conductor, an alternating electro-magnetic field is created at the same frequency as the alternating current. This electromagnetic field propagates in direction z (in a vacuum) at the speed of light C, and the magnetic field can be regarded as polarised in direction x and the electric field can be regarded as polarised in direction y. The electric field and the magnetic field are exactly 90 degrees out of phase. Because when the electric field reaches its peak amplitude, the magnetic field is momentarily zero, and when the magnetic field is at peak amplitude, the electric field is momentarily zero. In fact the rate of change of one field causes the other field.

That is basically the principal of an antenna or aerial. A wire suspended at 90 degrees to the ground, through which an alternating current is passed will cause an electromagnetic field to be induced. The field will propagate in a circular fashion, the waves radiating outward radially, so that the wave propagation front is a circle parallel to the ground with the centre at the aerial.

More complex antennae can be designed that focus the electromagnetic energy so that it propagates in a focussed direction.

This answer provided by Rob Sherratt, 18th Jul 2009

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How does an antenna work to receive and transmit radio signals?

An antenna works by converting electrical signals into radio waves for transmission and vice versa for reception. When an electrical current flows through the antenna, it creates electromagnetic waves that can travel through the air. These waves carry information in the form of radio signals. The antenna's design and length determine the frequency of the radio waves it can send and receive.


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In a transmitting antenna, electrical energy from the transmitter is converted into electromagnetic radiation (radio waves) for transmission. In a receiving antenna, electromagnetic radiation from incoming signals is converted back into electrical energy for the receiver to process.


How do radio antennas work to receive and transmit signals?

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Related Questions

What two functions does an antenna performs?

An antenna functions to receive electromagnetic signals from a transmitter and convert them into electrical signals for a device to process. It also transmits electrical signals from a device into electromagnetic signals to be sent to a receiver.


How did he generate and detect EM waves?

He generated electromagnetic waves by accelerating charges back and forth rapidly in an antenna. He detected the waves by using a similar antenna that would convert the electromagnetic waves into electrical signals.


How electromagnetic waves are detected?

Electromagnetic waves are detected using devices such as antennas, which convert the electromagnetic waves into electrical signals that can be processed and analyzed. These electrical signals are then used to detect properties of the electromagnetic waves, such as their frequency and intensity.


How does an antenna work to receive and transmit radio signals?

An antenna works by converting electrical signals into radio waves for transmission and vice versa for reception. When an electrical current flows through the antenna, it creates electromagnetic waves that can travel through the air. These waves carry information in the form of radio signals. The antenna's design and length determine the frequency of the radio waves it can send and receive.


What energy conversion takes place in a transmitting and receiving antenna?

In a transmitting antenna, electrical energy from the transmitter is converted into electromagnetic radiation (radio waves) for transmission. In a receiving antenna, electromagnetic radiation from incoming signals is converted back into electrical energy for the receiver to process.


How do radio antennas work to receive and transmit signals?

Radio antennas work by converting electrical signals into electromagnetic waves that can travel through the air. When a radio station transmits a signal, the antenna sends out electromagnetic waves. When a radio receiver picks up these waves, the antenna converts them back into electrical signals that can be processed and heard as sound. This process allows for the transmission and reception of radio signals over long distances.


What does an antenna do to receive and transmit signals?

An antenna receives and transmits signals by converting electrical currents into electromagnetic waves that can travel through the air. It acts as a bridge between electronic devices and the surrounding environment, allowing for the exchange of information wirelessly.


How microwave signal is detected?

Microwave signals are detected using an antenna that captures the incoming electromagnetic waves. The waves are then converted into electrical signals that are processed and analyzed by the detection system. The intensity and frequency of the electrical signals are used to interpret the incoming microwave signal.


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Antennas work by converting electrical signals into electromagnetic waves for transmission, and vice versa for reception. When a signal is sent through the antenna, it creates an electromagnetic field that propagates through space. This field can be picked up by another antenna tuned to the same frequency, allowing for communication.


Can RF signal travel in air medium without antenna?

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Do radio waves transfer energy?

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Is it possible to convert microwave signals into electrical signals?

NO