This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.
Microwave Communication & Considerable Parameters
Microwaves describes the contemporary current signals between 300 MHz to 300 GHz frequency ranges, microwaves have a resultant wavelength among ? = c/f = 1m and ? = 1mm respectively. These are ideal for transmission of data from one place to other because microwave power can infiltrate smog, rainfall, snow and clouds.
Microwave communication broadcast signals through radio using a progression of microwave towers. Microwave is a form of line of sight communication, because it requires the obstruction less transmission between the receiving and transmitting towers for signals to be communicated properly at both ends. After the successful effort of transmitting microwave message in 1940 from New York to Philadelphia, microwave communication is the most commonly used transmission technique for telecommunication services era.
With the continuous growth in cellular and satellite technologies, now microwave is less broadly used in telecom era. Communication is dominating towards the fiber optic data transmission. However, at various remote sites where economically it is not possible to install fiber optic cabling, microwave equipment is still in. Data communication through microwave occurs in both analog and digital formats. Whereas, digital format is the most advance type of microwave data communication.
Advantages of Microwave Communication over Fiber Optic
There are many convincing advantages of microwave radio over fiber optic cabling based transmission.
- Microwave link is possible to deploy in a day.
- Microwave link is flexible in the capacity that can be increase effortlessly at negligible or even no cost. Moreover, microwave radio link can be reinstalled depending on the customer requirement or if network demands changes. Therefore, loosing clients does not make a sense that assets are lost as in case of fiber optic.
- Microwave is easily crossable in terrain areas. Whereas, in various metropolitan cities and authorities, road digging is totally banned to deploy fiber optic or prohibited or even expensive.
- Microwave radio infrastructure is owned by operator therefore, no dependence on competitors.
- Microwave radio infrastructure is already available for various networks in the shape of rooftops, cellular poles and residing towers of microwave radio transmission.
- Microwave radio systems are not inclined to common disastrous breakdown of fiber cable systems occurred by cable cuts, it may be fixed in no time rather than waiting for hours or days.
- It is controllable in the time of natural disasters for example flood, earthquakes.
- Operational cost is minimal recurring.
Any conductor that can intercept an RF field can be an antenna. The Basic Principle of Microwave antennas are similar to those of antenna used at lower frequencies. Basically an antenna converts RF power into Electromagnetic radiation. More briefly an antenna is transducer which is specially designed to transmit and receive electromagnetic wave. A good transmitting antenna is often a good receiving antenna. For designing wireless systems, engineers must select an antenna that fulfils the system's requirements to firmly close the link between the remote points of the communications system.
The Isotropic Antenna
Isotropic antenna radiates uniformly in all directions around the area Fig3.2. Isotropic antennas are having solitary divergence properties which cannot be taken in practice. It is difficult to attain in actual. If it did present then it can be figure out in a mathematical way. This antenna is instantly used as reference antenna and calculated in decibels (dBi) over isotropic.
Considerable Parameters of Antenna
There are several critical parameters that affect an antenna's performance and can be adjusted during the designing process . The most considerable parameters are:
- Radiation Pattern
- Input Impedance
The radiation pattern of an antenna is the geometric pattern of the relative field strengths of the field emitted by the antenna. For the ideal isotropic antenna, this would be a sphere. For a typical dipole, this would be a toroid. The radiation pattern of an antenna is typically represented by a three dimensional graph, or polar plots of the horizontal and vertical cross sections. The graph should show side lobes and back lobes, where the antenna's gain is at a minima or maxima .
Input Impedance is the most important parameter that's related to the antenna and its transmission line. It is used to determine the transferring power from the antenna to transmission line and vice versa. Between antenna and transmission line the Impedance match is expressed by the term Standing wave ration (SWR) or reflection coefficient and is expressed in decibels.
"The polarization of an antenna is defined as the polarization of the electromagnetic wave radiated by the antenna along a vector originating at the antenna and pointed along the primary direction of propagation. The polarization state of the wave is described by the shape and orientation of an ellipse formed by tracing the extremity of the electromagnetic field vector versus time. Although all antennas are elliptically polarized, most antennas are specified by the ideal polarization conditions of circular or linear polarization." 
Antenna Directivity means that maximum antenna gain compared with its gain that is averaged in all direction. Directivity go antenna always independent of its radiation efficiency.
The hypothetical isotropic antenna radiates power equally in all direction and we measure any real type antenna gain with compare to the isotropic antenna. Actually the antenna gain means the amount of energy radiate in the direction compared to the isotropic antenna radiate the amount of energy in same direction. We are basically interested on maximum gain and maximum gain is that the direction antenna radiates most power.
Antenna effectiveness usually depends upon its ability to radiate energy into the air. We can say antenna is efficient when it wastes very little energy during the radiation process. The efficiency of an antenna is usually referred to as the POWER GAIN as compared to a standard reference antenna. The power gain of an antenna is a ratio of the radiated power to that of the reference antenna, which is usually a basic dipole. Both antennas must be fed RF energy in the same manner and must be in the same position when the energy is radiated .