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INTRODUCTION TO MICROWAVE COMMUNICATION HISTORY OF MICROWAVE h i s t o r y o f m i c r o w a v e Invented accidentally by Dr.Percy LeBaron Spencer. While testing a magnetron during work, he discovered the candy bar in his pocket melted. Experimented with other food products (popc...

INTRODUCTION TO MICROWAVE COMMUNICATION HISTORY OF MICROWAVE h i s t o r y o f m i c r o w a v e Invented accidentally by Dr.Percy LeBaron Spencer. While testing a magnetron during work, he discovered the candy bar in his pocket melted. Experimented with other food products (popcorn and eggs), and realized microwaves can cook food quickly. HISTORY OF MICROWAVE h i s t o r y o f m i c r o w a v e At 1947, 1st commercial microwave oven was produced called Radarange, it is mostly used by restaurants, railroad cards, liners and military. Improvement and refinement was made in 1967. The 1st domestic microwave oven. MICROWAVE ELECTROMAGNETIC m i c r o w a v e SPECTRUM MICROWAVE m i c r o w a v e Microwaves are frequencies that fall between radio communication frequencies and optical frequencies (infrared, visible, and ultraviolet light). They include ultrahigh, superhigh, and extremely high frequencies. Microwaves offer significant benefits for radio communication due to their short wavelengths. MICROWAVE m i c r o w a v e The advantages of using microwaves outweigh any associated problems. Most new communication services and equipment now utilize microwaves. MICROWAVE m i c r o w a v e It has electromagnetic radiation that ranges between 3 GHz to 300 GHz. They fall in between the infrared and radio waves in electromagnetic radiation.  WAVE PROPAGATION Space Wave Sky Wave Surface Wave  GROUND WAVE/ SURFACE WAVE Travel around the curvature of the earth, sometimes right around the globe.  GROUND WAVE/ SURFACE WAVE What frequency is the best? Low or High. What is the polarization? Vertical or Horizontal.  GROUND WAVE/ SURFACE WAVE Use vertical polarization to reduce attenuation. Utilizes frequencies below HF range, and losses with increasing frequency. The higher the frequency , the shorter the wavelength, means more prone to absorption. SPACE WAVES Travel in troposphere; the portion of the atmosphere closest to the ground. Depend mostly on line-of- sight conditions, a space wave is limited in propagation by the curvature of the earth. SPACE WAVES Caused by the varying density of the atmosphere due to diffraction around the curvature of the earth..  SKY WAVE The wave strikes the ionosphere and is refracted back to the ground. Utilizes frequencies in the HF range and sometimes frequencies just above or below.  IONIZATION occurs when high energy ultraviolet light waves from the sun enter the ionospheric region of the atmosphere, strike a gas atom, and literally knock an electron free from its parent atom.  The lowest, existing at an average height D-LAYER of 70 km, with an average thickness of 10 km. The least important layer in HF propagation. This layer has the ability to refract signals of low frequencies. High frequencies pass right through it and are attenuated.  E-LAYER Existing at about 100 km in height, with thickness of 25 km. This layer has the ability to refract signals as high as 20 MHz. For this reason, it it valuable for communications in ranges up to about 1500 miles. This layer is also known as KENELLY- HEAVISIDE LAYER.  E-LAYER SPORADIC Thin layer of very high ionization density, sometimes making an appearance with the E-layer. F-LAYER During the daylight hours, the F layer separates into two layers, the F1 and F2 layers. It is the layer that is responsible for high-frequency, long-distance transmission. LAYER HEIGHT IN THICKNESS SINGLE-HOP KM IN KM RANGE IN KM D 50-90 10 E 110 25 2350 F_1 175-250 20 3000 F_2 250-400 200 3840 (d) 4130 (n) ASSIGNMENT #01 Memorize the electromagnetic spectrum.