This article covers the different types of antennas and how they work. Antennas are used in a variety of applications, from cell phones to satellite dishes.
The 5 Different Types of Antennas
There are five main types of antennas- dipole, monopole, microstrip, antenna array, and reflector.
Dipoles are the most common type of antennae. They consist of two pieces of metal (called conductors) that are split in the middle and bent to resemble the letter “V”. The two parts are connected to the radio through a feedline. Dipoles can be used for both transmitting and receiving signals.
Monopoles are similar to dipoles, but instead of having two conductors, they only have one. The single conductor is attached to the ground (usually through a metal rod), and the other end is connected to the radio. Monopoles are generally smaller and more compact than dipoles, making them ideal for portable devices like cell phones.
Microstrip antennas are made up of a conductor strip placed on top of a dielectric material (often FR4). They are commonly used in mobile devices like laptops and smartphones because they can be printed directly onto circuit boards. In addition, microstrip antennas typically have good impedance matching, which makes them efficient at transferring energy between the antenna and the radio.
Antenna arrays are made up of multiple antennas that work together to focus or redirect the signal in a specific direction. This type of antenna is often used in satellite communication systems where it’s important to aim the signal precisely at another location thousands of miles away. Arrays can also be used for analyzing waveforms or for radar applications.
Reflector antennas use one or more large metal surfaces to reflect incoming radio waves onto an active element like a dipole or patch antenna. This type of antenna is often used in long-range applications like wireless internet service providers (WISP) or broadcast towers where it’s essential to extend the range without increasing transmit power levels.
Dipole Antenna
Dipole antennas are the most common type of antenna used in radio communications and are used in everything from shortwave radios to cell phones. Dipoles are simple to construct and can be made from various materials.
Dipole antennas consist of two conductive elements, called "poles," separated by an insulator. One pole is connected to the positive side of a power source, while the other is connected to the negative side. When dipoles are excited by an electric current, they produce electromagnetic fields that can be used to transmit or receive radio waves.
Dipoles can be oriented in several ways, depending on their intended use. For example, they can be arranged horizontally, vertically, or at any angle. The orientation of a dipole has a large impact on its radiation pattern - that is, the shape of the electromagnetic field it produces. Horizontal dipoles radiate equally in all directions perpendicular to the antenna (think of them as "beaming" sideways), while vertical dipoles radiate equally in all directions parallel to the antenna (think of them as "beaming" up and down).
The length of each pole also affects the performance of the antenna. In general, longer poles will result in better performance - that is, they will radiate more effectively over longer distances - but this comes at the cost of increased size and weight. As such, there is often a trade-off between size/weight and performance when selecting antennae for portable devices like cell phones.
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Loop Antenna
A loop antenna is a radio antenna consisting of a loop or coil of wire, tubing, or other conductive material, often fed by a balanced source such as a transformer. They are the most common type of antennae at HF. Loop antennas have the advantage of being sensitive to signals perpendicular to the plane of the loop (in other words, they can be more directional than simple dipoles when used in this manner) while still having low loss if installed correctly. When used as receiving antennas, large loops can be very effective at mitigating man-made noise (such as electrical interference from household appliances)