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After the antenna parameters discussed in the previous chapter, another important topic of consideration is the near field and the far field regions of the antenna. The radiation intensity when measured nearer to the antenna, differs from what is away from the antenna. Though the area is away from the antenna, it is considered effective, as the radiation intensity is still high there. Near Field The field, which is nearer to the antenna, is called as  near-field . It has an inductive effect and hence it is also known as  inductive field , though it has some radiation components. Far field The field, which is far from the antenna, is called as  far-field . It is also called as  radiation field , as the radiation effect is high in this area. Many of the antenna parameters along with the antenna directivity and the radiation pattern of the antenna are considered in this region only. Field Pattern The field distribution can be quantifying in terms of field intensity is r...

The basic communication parameters are discussed in this chapter to have a better idea about the wireless communication using antennas. The wireless communication is done in the form of waves. Hence, we need to have a look at the properties of waves in the communications. In this chapter, we are going to discuss about the following parameters − Frequency Wavelength Impedance matching VSWR & reflected power Bandwidth Percentage bandwidth Radiation intensity Now, let us learn them in detail. Frequency According to the standard definition, “The rate of repetition of a wave over a particular period of time, is called as  frequency .” Simply, frequency refers to the process of how often an event occurs. A periodic wave repeats itself after every  ‘T’  seconds (time period).  Frequency  of periodic wave is nothing but the reciprocal of time period (T). Mathematical Expression Mathematically, it is written as shown below. f = 1 T " role="presentation"> [Math Proces...

A person, who needs to convey a thought, an idea or a doubt, can do so by  voice communication . The following illustration shows two individuals communicating with each other. Here, communication takes place through  sound waves . However, if two people want to communicate who are at longer distances, then we have to convert these sound waves into  electromagnetic waves . The device, which converts the required information signal into electromagnetic waves, is known as an  Antenna . What is an Antenna ? An Antenna is a transducer, which converts electrical power into electromagnetic waves and vice versa. An Antenna can be used either as a  transmitting antenna  or a  receiving antenna . A  transmitting antenna  is one, which converts electrical signals into electromagnetic waves and radiates them. A  receiving antenna  is one, which converts electromagnetic waves from the received beam into electrical signals. In two-way communicat...

D Band D Band defined by NATO Frequency Range: 1 to 2 GHz Wavelength: 3 to 1.5 dm

F Band F Band defined by NATO Frequency Range: 3 to 4 GHz Wavelength: 1 dm to 7.5 cm

IEEE Radar W Band Frequency Letter Band W-Band Frequency Range 75 to 110 GHz Wavelength 2.7 mm to 4 mm The  W-band  as defined by IEEE is a frequency range from 75 to 110 GHz. IEEE uses  letters to signify a range of frequencies  from 1 to 170 GHz. The W band overlaps with the NATO designated M band (60 to 100 GHz). This band is used for a wide range of applications including automotive radars, satellite communication, astronomy, defense, and security applications. The segment from 71 to 76 GHz and 81 to 86 GHz is designated by the International Telecommunication Union for satellite services. The 77 GHz frequency window is also used for automotive radars.  IEEE/Radar Letter Frequency Bands .

IEEE Radar V Band Frequency Letter Band V-Band Frequency Range 40 to 75 GHz Wavelength 4.0 mm to 7.5 mm The  V-band  as defined by IEEE is a frequency range from 40 to 75 GHz. IEEE uses  letters to signify a range of frequencies  from 1 to 110 GHz. The V-Band is license free in many countries and is most often used for wireless backhaul and point to point/point to multi-point radio links. These systems are primarily used for high capacity, line of sight communications. Availability of a wider bandwidth made this band a hit in the point-to-point (pt-to-pt) radio solution market. Radio links operating in the V band can be densely deployed in congested cities without interference, and without need for digging for cables and fiber optics, which can be costly, slow and highly disruptive. Radios providing full-duplex data rates up to 10 Gbps over distances close to one mile or more are easily available today. In 2013, IEEE introduced the 802.11ad wireless access systems (a...