In any type of wireless infrastructure, one of the most visible features you may notice is the antenna. An antenna is extremely important in LAN, radio, etc. You will need an antenna to make sure that your wireless network works effectively and efficiently. Whether you have an outdoor, office, or a home wireless network, it is important that you have a good antenna. There are various types of antennas and each of them has its own distinct specifications. To help you in choosing the right one, it is important that you understand the nature of these antennas.
What is an Antenna?
Generally, an antenna can transmit and receive signals, which translates into some information. Antennas were first introduced by the Germans in the year 1888. They are generally designed for wireless communication. At the same time, an antenna also has the ability to generate both microwave and radio signals. Essentially, it is just similar to a conductor and the resonant device, which are used for extremely narrow frequency bands.
What Are the Different Types of Antenna?
Basically, antennas are classified into different types depending on their shape and functionality. The following are some of the most highly recognized types of antenna.
Aperture Antenna
This type of antenna comes with an opening that has the ability to radiate energy. The opening is referred to as the aperture. Aperture antennas have the ability to send and receive signals from different directions. At the same time, the radiation is also more powerful compared to the two-wire transmission line. These types of antennas are commonly used for microwave applications and surface search radars. One of the most popular aperture antennas is the horn antenna.
Yagi-Uda Antenna
Yagi-Uda, also referred to as the Yagi, is best known as a directional antenna. It is considered one of the most typical types of antenna. Generally, they are utilized for household appliances such as radios and television sets. In this particular type of antenna, a lot of parallel elements, such as half-wave dipoles, are placed in a single straight line. Yagi-Uda is utilized as a bridge in TV reception.
Wire Antenna
A wire antenna is a radio that is composed of a long wire. Furthermore, its wavelength is not dependent on the length of the wire antenna. In order to effectively transmit and send signals, a cable will be linked to the receiver or transmitter through the antenna tuner. Most people prefer to use this type of antenna because it is very easy to install and very portable too. Wire antennas come in different types, including Monopole antenna, Helix antenna, and Dipole antenna.
Lens Antenna
This type of antenna uses an electromagnetic lens. To transmit and receive signals, it will utilize the divergence and convergence property of the lens. It includes a dipole antenna along with a lens. The size of the lens that will be used should be reversely proportional to the frequency of the transmitted or received signal.
The lens will converge the signals found at the feeding antenna. This type of antenna is greatly recommended for high-frequency transmission which requires high bandwidth. Generally, there are two types of lens antennas. These are the Metal plate Antennas and the Di-electric Lens Antennas.
Reflector Antenna
This type of antenna includes one or more reflective surfaces along with a system that is responsible for absorbing or transmitting the electromagnetic waves. Generally, these antennas are used for remote sensing, as well as satellite communication. Some examples of reflector antennas are corner reflectors and parabolic reflectors.
What Are the Properties of Antennas?
The following are some of the properties of antenna:
Gain
Gain refers to the intensity of the waves being transported by these antennas. They are designed in such a way that the radiated power is maximized to the intended direction while introducing the concept of directivity. Mathematically, we can express antenna gain as Directivity multiplied by Efficiency.
In this case, the directivity of the device refers to the focus of the radiation pattern in a particular direction. While the efficiency will consider the loss caused by faults including the resistance, manufacturing faults, VSWR, etc.
Polarization
When it comes to the polarization of the antenna, it will take into account the polarization of the fields that are being transported by the device. This is a very relevant factor, especially when you are conducting device-to-device communication. Keep in mind that the waves that are being released by these devices are polarized diversely.
If it is horizontal, then it also follows that the EM vector is horizontal. Furthermore, these horizontal devices are designed to receive them. The same process will also be applied for vertical polarization. It is also possible that circular polarization occurs wherein there will be a combination of horizontal waves and vertical waves.
Bandwidth
The range of frequencies on which they can operate properly is known as the bandwidth of the device. It refers to the range in Hz wherein the value of SWR is less than 2.1.
Effective Length
When it comes to the length, both the transmitter and the receiver should be measured. The efficiency of this will be based on these factors. The effective length refers to the free space length found in any conductor. The effective length can be expressed in the formula, which is the Distribution of non-uniform area divided by the Uniform current distribution area.
Polar Diagram
The polar diagram of the antenna refers to the radiation pattern of the device. This is also considered the most relevant property of the antenna. It illustrates the power field strength in diverse angles of the horizontal and vertical planes.
How Do Antennas Work?
The antenna works by collecting and transmitting electromagnetic radiation. First of all, the electrical signals are gathered from the transmission line, afterward, they will be transformed into radio signals. This is also the same procedure being done on the receiving end, but in the opposite way. It will receive the radio waves, afterward, it will be converted into electrical signals.
The transmission will generate electromagnetic waves. Once the charge oscillates, there will be a variation in the electric field. The changes in the electric field can result in the displacement current.
Maxwell’s equations are applied in the process of this device. Once the electric field is produced, the magnetic field is also produced. When it comes to the computation of the electric and magnetic field generation, Ampere’s law is applied.
The energy that gets into the device will then be converted into Electromagnetic waves. These waves will then be radiated by the signal’s current. The transformation of the magnetic field into the electric field will be accomplished by using Faraday’s law.
What Are the Applications of Antenna?
The antenna is considered the major element of the wireless communication system. Every type of antenna has its own particular task. At the same time, it also has its own advantages and disadvantages.
In fact, all the communication that surrounds you is probably using an antenna. Aside from this, modern devices are also utilized in searching for radars and defense radars. Keep in mind that these devices can also help in treating breast cancer, which is considered a new area of research.
Transmitters and Receivers
The focal point of radio communication is the utilization of transmitters and receivers. The transmitter will be responsible for sending the signals. These signals will follow a certain path towards the receiver. The receiver will then decipher the signal in order to obtain the message.
Transmitters and receivers are composed of various parts and most importantly an antenna. The antenna that you use in receiving signals for your car radio, satellite television, etc. is known as the receiver. The shape, size, and scope of these antennas will be dependent on the goals of the sender, as well as the distance that the signal must reach.
What Are the Fundamentals of Transmission?
The process of transmission requires some technical concepts. However, understanding the fundamentals of transmission is not actually hard. To ensure that the transmitter will be able to send a signal via the antenna, it is important that an electrical current must be launched through the antenna and a magnetic field will be produced. Rather than simply sending out signals at a certain frequency, the antenna will send out signals that have modulated frequency or amplitude.
Information is collected in radio waves through amplitude modulation (AM) and frequency modulation (FM). These are the two common methods that are being used. Once you go to a particular frequency on your radio station, you might notice that you are receiving a lot of information.
What is Reception?
The modulated signal will travel through the air at a particular wavelength, and it will be accepted by the antenna. The signal that contains the information is known as the carrier signal. The signal that has been modulated and sent out into the airwaves is called a carrier signal since it carries information.
The signal will be modulated so it can be converted into a carrier signal. Consequently, it will be demodulated once it lands on the receiver. This means that the signal will be reduced down to its relevant information.
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