How Does an Antenna Work?

Antenna is used widely in the telecommunication field, military operations, and other applications. It gets an electromagnetic wave and converts it into electric signals. Some antennas receive electric signals and radiate them as electromagnetic waves. A simple radio antenna is a long straight rod. Many indoor TV antennas take the form of a dipole that is divided into 2 pieces and folded horizontally. Numerous outdoor TV antennas have more than one dipole with a central supporting rod. The different types of antenna designs include parabolic satellite dishes and circular loops of wire.

Generally, the waves emitting at the antenna from a transmitter are the same in any shape of the antenna. Different patterns of dipoles help to concentrate the signals for easy detection. This effect can be increased by adding many unconnected dummy dipoles called reflectors and directors. These dipoles bounce the signals over the actual receiving dipoles. This is similar to boosting the signals and picking weaker signals better than a simple antenna. We will further discuss the working of different kinds of antennas and the science behind their working. We will also discuss the various types of antennas and their different properties.

Important Features of Antennas

An Antenna contains many important features such as:

·      Gain

The gain of an antenna is a technical measurement and the amount at which the signals are boosted. Television will pick up a poor signal without an antenna plugged in. Metal cases and other components pick up some kinds of signals by default. You need to add a proper directional antenna to gain better signals.

The gain of an antenna is often measured in decibels (DB). You will receive a better reception with a bigger gain. Outdoor antennas work more effectively than outdoor antennas.

·      Directionality

Dipole is very directional and picks up incoming radio waves traveling at right angles to them. The telescopic antenna on an FM radio is less directional when the signals are strong. If the telescopic antenna is pointed straight upward, it will capture good signals from any direction.

AM antenna in the radio is very directional. While using AM, you will need to swivel the radio until it picks up strong signals. Highly directional antennas give ample benefits such as reduction in interference from unwanted sources or signals.

·      Bandwidth

 The bandwidth of an antenna refers to the frequency range on which it works perfectly. Broader bandwidth gives a greater range of radio waves. Broad bandwidth will be more helpful in the case of television but not in other cases like satellite communications, telephones, or cell phones.

Different Kinds of Antennas

An antenna is a tool used for receiving and transmitting signals. It comes in various shapes, sizes, and features according to the needs of the customers. We will now discuss the different types of antennas and how they work.

1. Dipole Antenna

Dipole antennas normally contain 2 similar conductive elements like rods or metal wires. This kind of antenna includes odd and even modes. It contains a center-fed driven element to transmit and receive radio frequency energy. It is the simplest type of antenna containing a straight electric conductor made of metals like copper thereby making 2 poles.

The metal wire length is half of the highest wavelength in free space at the frequency operation. The conductive materials in the center of an antenna are divided through an insulator known as an antenna section. The RF voltage source is normally given to the middle of the Dipole Antenna. Voltage and current are then supplied via the 2 conductive elements to produce radio or electromagnetic signals. These signals are later radiated outside the dipole antenna. In the center of a dipole antenna, the voltage is minimum and current is maximum whereas the current is minimum and voltage is maximum at the two ends of an antenna.

2. Grid Parabolic Antenna

Grid antenna is a kind of parabolic antenna. It normally contains a reflector made from a grill of parallel wires or bars targeted in one direction that acts as a polarizing filter and a reflector. These antennas normally reflect linearly polarized radio waves with an electric field parallel to the grill elements. The spacing of the grid elements is frequently dependent and inversely proportional to the frequency.

Grid parabolic antenna has the highest weight ratio and strength. It is a very efficient antenna in which gain figures approach the theoretical maximum for the curved surface area. This antenna contains a full Parabolic reflector for a smooth digital communication system.

3. Yagi Antenna

The Yagi antenna was discovered by 2 Japanese scientists Shintaro Uda and Hidetsugu Yagi. It is a kind of directional antenna and is generally used in point-to-point communication. Yagi antenna radiates signals in one fixed direction. It includes a long transmission line with a single driven element containing two rods connected on any one side of the transmission lines.

This antenna contains a single reflector on one side of the transmission line and several parasite elements that act as directors. In Yagi antennas, the reflector is kept behind the driven element and is longer than the driven element. On the other hand, the director is kept on the front of the driven element and is shorter than the driven element. Normally, Yagi antennas have one reflector and multiple directors.

4. Satellite dish antenna

Dish Antenna are popular these days. They contain 2 major components namely parabolic shaped reflector and a low noise block down convertor. Parabolic dish gets electromagnetic signals from the satellite and focuses them on LNBF.

Final words

This is all about a High Gain Antenna with its working pattern, design and features. The working of every kind of antenna is almost similar with slight changes. These antennas are used in multiple applications from satellite communication to telephone lines. Many antenna manufacturers and dealers sell the different kinds of antennas online at affordable rates.