Telecom | Microwave

Microwave Signal

Many of us were aware about the signal and microwaves. Microwave is one of the telecommunication basic physics and relates to Signal, frequency. In a generic concept, microwave is one type of electromagnetic radiation which have wave lengths range between 1 Meter to 1 Millimeter and have the frequency between 300 Mhz to 300 Ghz. 

In general Microwave signals travels in air medium, and in line of sight. They are used for point-to-point communication or we can say literally as tower to tower communication. Earlier long distance telephone communications were made through narrow beam radio microwave signals. Most of the microwave applications were used between 1-40 GHz.  

SL	Band Name	Frequency in GHz/MHz
1	L Band	1-2 GHz
2	S Band	2-4 GHz
3	C Band	4-8 GHz
4	X Band	8-12 GHz
5	Ku Band	12-18 GHz
6	K Band	18-27 GHz
7	KA Band	27-40 GHz
8	HF Band	3-30 MHz
9	VHF Band	30-300 MHz
10	UHF Band	300-1000 MHz
11	Radio Broadcast	550 KHz- 1600 KHz (AM) 88 KHz-108 MHz (PM)

Many applications work within the above specified range such as RADAR, TV Broadcast, Military Communication, Maritime Communication, Radio Broadcast, Satellite Communication, Mobile Communication, etc. In General, for home use TV and Radio sets use UHF and VHF frequency band for operation. 

Similarly, L Band Frequency Radars working are mostly used for clear air turbulence studies. For weather monitoring, S Band is used. Because of the smaller wavelength the X Band RADAR sensitive enough to detect tiny particles in air even water droplets. The X Band are being used at major airplanes.  

A Microwave System

A microwave system used for microwave signal generation and transmission normally consists of a transmitter unit, including a microwave oscillator, wave guides and a transmitting antenna or RADIO device, and a receiver unit that includes a receiving antenna, transmission line or wave guide, a microwave amplifier, and a receiver unit.

For Microwave sources, components used such as Cathode tube, Gunn Diode, Reflex Klystron and Magnetron are used. 

Gunn diodes have been found a very effective method of generating microwave signals anywhere from around 1 GHz up to frequencies of possibly 100 GHz. It may also be used for amplifier and it does not contain PN type junction. 

Later we will learn more concepts on other telecommunication systems.

-DR