Antenna – Overview

Introduction

An antenna is a metallic framework or a transducer converting electrical current to transmit and/or receive electromagnetic energy (radio waves). The said energy can occur in light waves, radio waves, cell phone signals, and radar signals.

How does an Antenna Function?

Antennas have several uses. In communication, there are two antennas: a transmitter and a receiver. First, the information is converted into an electrical current and sent to a transmitter. Subsequently, it transfers the electrical current through the transmitter’s antenna and emits electromagnetic radio waves.

The receiver’s antenna detects and absorbs the radio waves, causing vibration to the electrons in the antenna. As a result, the structure transmits this electrical current to various telecommunications devices like radio receivers, televisions, or other devices. Finally, the signal is converted into sound, television images, or other information transmitted.

Types of Antennas:

Antennas come in different types according to their functionality and use. Some of the familiar types are as follows:

1. Yagi-Uda: This type is the directional antenna, the most public type of antenna used in old household appliances like TVs and radios. In this type, multiple elements are arranged in a single straight line. Its uses extend as a channel in TV reception.
2. Dipole: In this type, the elements form like a two-rod design, and its uses extend to Wi-Fi or radio.
3. Parabolic Reflector: It consists of one or more reflecting surfaces and has a system absorbing and transmitting electromagnetic waves. Their uses are primarily for satellite communications and remote sensing.
4. Lens: This type of antenna is embedded with an electromagnetic lens and utilizes the lens’s convergence and divergence property to receive and transmit signal. The lens’s range varies inversely with the signal frequency intended for transmission or reception.
5. Aperture: A type with an opening capable of radiating energy is known as the Aperture antenna. These types can transmit and receive signals in all directions. In addition, the radiation is more significant than the two-wire transmission line.

What are the Properties of Antenna?

Following are a few common properties of antenna:

Gain

It designates the ability of the antenna to influence the effectiveness of transmitting or receiving the signals through proper focus and directions.

Bandwidth

This property defines the range of frequencies to enhance the antenna’s influence and ensure better performance.

Polarization

It refers to the positioning of electromagnetic waves, such as vertical, horizontal, or circular polarization in relation to the Earth’s surface. Moreover, if the wave’s polarization is in the vertical direction, it requires the antenna to be positioned vertically.

If vector E is horizontal, it requires a horizontal antenna to initiate it. In the case of circular polarization, the waves form horizontally and vertically.

Effective Length

It is the parameter exemplifying the effectiveness of the transducers in transmitting and receiving electromagnetic waves.

Effective Length = (non-uniform current distribution area)/( uniform current distribution area).

Applications of Antenna:

Various applications across different industries utilize antennas; here are some common applications:

Wireless Communication: Mobile phones, Wi-Fi routers, and other wireless devices.

Broadcasting: Radio and TV stations.

Satellite Communication: Supports weather monitoring and global communication systems.

Radar Systems: Antennas in radar systems detect and track objects and are used for air traffic control, military, and weather monitoring.

Navigation Systems: In the GPS, antennas receive signals from satellites to determine accurate locations to aid navigation in vehicles, ships, and aircraft.

Medical Imaging: Medical devices such as magnetic resonance imaging (MRI) machines for transmitting and receiving signals.

RFID Systems: These systems, through the help of an antenna, communicate with RFID tags to enable applications like access control and inventory tracking.

Conclusion:

In summary, antennas are fundamental across various purposes, filling in as the spine for distant communication, remote distinguishing, radar structures, and more. Furthermore, their varying functionalities and designs deal with the continuously forming prerequisites of organizations, enabling stable connectivity, viable data transmission, and significant level mechanical capacities.

Lastly, from the universal antennas in our phones to the perplexing radar arrays in avionics, antennas’ flexibility and resolute nature highlight their significance in current development. As technology progresses, transducers will be, beyond a shadow of a doubt, a central part in shaping the possible destiny of communication and connectivity across countless sectors.