Microwaves

Microwaves are electromagnetic waves whose frequencies range from 1GHz to 1000 GHz(1Ghz=1000000000 Hz).For comparison, the signal from an AM Radio station is 1 MHz (Mega Hertz=1000000 Hz)and the signal from FM radio station is 100 MHz.

Microwave( µ w's)   are so called since they are defined in terms of their wavelength in the sense that micro refer to tinyness-tinyness referring to the wavelength and the period of a cycle of a cm wave.In other words, the wavelength( λ) of cm waves at microwave frequencies are very shorts;typically  from a few tens of cm to a fraction of a mm.In short, a microwave is a signal that has a wavelength of 1 foot or less i.e,  λ<= 30.5 cms =~ 1 foot. This converts to a frequency of 984 MHz, approximetly= 1 Ghz.so,all frequencies above approximately 1000MHz (1GHz) to about 1000 GHz are microwave frequencies.

The higher frequency edge of microwaves borders on the infrared and visible-light regions or spectrum.This explains why microwaves behaves more like rays of light rays of light than ordinary radio waves. Due to this unique behaviours,microwave frequencies are classified separately from radio waves.

The visible light is above infrared region and falls between 430 THz and 1 PHz(peta Hz)This region includes the a fiber optics and laser region.This region above 1 PHz includes X-rays,Gamma Rays and cosmic Rays. 

ADVANTAGE OF MICROWAVES

1. Increased bandwidth availability 

Microwave have large band width(1GHz-103GHz) compared to the common bads namely MW,SW and UHF waves. The advantage of large bandwidths is that the frequency range of information channels will be  a small percentage of the carrier frequency   and more information can be transmitted in microwave region is very useful since the lower band of frequency is already crowded.

 Infact,Microwave region(1000 GHz)contain thousand sections of frequency band 0-100000000 Hz and hence any one of these thousand section may be used to transmit all the TV, ratio and other communication that is presently transmitted by the 0-10000000 Hz band.(Bandwidth of speech = 4 kHz;Music=10-15kHz. T.V=5-7 MHz; Telegraph channel=120-240Hz),i.e., greater bandwidth provides more room for stuff to be packed into the transmission.

 It is a current trend to use microwaves more and more in various long distance communication application such as Telephone networks, TV network,space communication ,Telemetry ,Defence, Railways, etc. FM and present day digital modulation schemes also require higher bandwidth.