1. Microwaves
Saja Ghazi Omar

2. What is a Microwave
History of Microwave
Microwave Sources
Uses of a Microwave
Microwave Frequency Measurements
Theory
Effect on Health
Referfnces

3. What Is a Microwave

6. History 1846 Maxwell predicted the radio waves from his equations.
1888,  Hertz  was the first to demonstrate the existence of radio waves by building a spark gap radio transmitter that produced 450 MHz microwaves, in the UHF region.

7. 1894 Indian radio pioneer Jagdish Bose publicly demonstrated radio control of a bell using millimeter wavelengths, and conducted research into the propagation of microwaves.
1943, the Hungarian engineer Zoltán Bay sent ultra-short radio waves to the moon.

8. Microwave sources
High-power microwave sources use specialized vacuum tubes to generate microwaves.
Low-power microwave sources use solid-state devices such as thefield-effect transistor (at least at lower frequencies) tunnel diodes, Gunn diodes

9. Heating and power application Spectroscopy
Uses
Communication
Radar
Radio astronomy
Heating and power application
Spectroscopy

10. Microwave frequency bands
The microwave spectrum is usually defined as electromagnetic energy ranging from approximately 1 GHz to 100 GHz in frequency, but older usage includes lower frequencies. Most common applications are within the 1 to 40 GHz range.

11. military telemetry, GPS, mobile phones (GSM), amateur radio S band
Letter Designation
Frequency range (GHz)
Wavelength range (mm)
Typical uses
L band
1 – 2
150 – 300
military telemetry, GPS, mobile phones (GSM), amateur radio
S band
2 – 4
weather radar, surface ship radar, and some communications satellites (microwave ovens, microwave devices/communications, radio astronomy, mobile phones, wireless LAN, Bluetooth, GPS)
C band
4 – 8
37.5 – 75
long-distance radio telecommunications
X band
8 – 12
25 – 37.5
satellite communications, radar, terrestrial broadband, space communications
Ku band
12 – 18
16.7 – 25
satellite communications
K band
18 – 26.5
11.3 – 16.7
radar, satellite communications, astronomical observations
Ka band
26.5 – 40
5 – 11.3
Q band
33 – 50
6 – 9
satellite communications, terrestrial microwave communications, radio astronomy
U band
40 – 60
5 – 7.5
V band
50 – 70
4 – 6
millimeter wave radar research and other kinds of scientific research
E band
60 – 90
3.3 – 5
UHF transmissions
W band
75 – 110
2.7 – 4
satellite communications, millimeter-wave radar research, military radar targeting and tracking applications
F band
90 – 140
2.1 – 3.3
SHF transmissions: Radio astronomy, communications, wireless LAN, communications satellites, satellite television broadcasting,
D band
1.8 – 2.7
EHF transmissions: Radio astronomy, microwave remote sensing, amateur radio, directed-energy weapon, millimeter wave scanner

12. Microwave frequency measurement
Microwave frequency can be measured by either electronic or mechanical techniques.
Frequency counters or high frequency heterodyne systems can be used. Here the unknown frequency is compared with harmonics of a known lower frequency by use of a low frequency generator, a harmonic generator and a mixer. Accuracy of the measurement is limited by the accuracy and stability of the reference source.
Mechanical methods require a tunable resonator such as an absorption wavemeter, which has a known relation between a physical dimension and frequency.

13. Theory
The amount of radiation that can be absorbed by a body can be determined according to Beer’s Law:
Energy transferred from an electromagnetic wave which travels through space into a receiver objects, The rate of energy transferred per unit area called power density:
S = E × H

14. Specific absorption rate (SAR) is defined as the time derivative of the incremental energy (dW) absorbed by an incremental mass (dm) contained in volume (dv) of a given mass density (ρ).

15. Effects on health
Microwaves do not contain sufficient energy to chemically change substances by ionization, and so are an example of non ionizing radiation. The word "radiation" refers to energy radiating from a source and not to radioactivity. It has not been shown conclusively that microwaves (or other non ionizing electromagnetic radiation) have significant adverse biological effects at low levels. Some, but not all, studies suggest that long-term exposure may have a carcinogenic effect. This is separate from the risks associated with very high intensity exposure, which can cause heating and burns like any heat source, and not a unique property of microwaves specifically.

16. References
 Pozar, David M. (1993). Microwave Engineering Addison– Wesley Publishing Company. ISBN
R. Sorrentino, Giovanni Bianchi, Microwave and RF Engineering, John Wiley & Sons, 2010, p. 4
 Microwave Oscillator notes by Herley General Microwave
 Sisodia, M. L. (2007). Microwaves : Introduction To Circuits,Devices And Antennas. New Age International. pp. 1.4–1.7. ISBN 
Liou, Kuo-Nan (2002). An introduction to atmospheric radiation. Academic Press. p. 2. ISBN  Retrieved 12 July 2010.
 "IEEE : Mobile Broadband Wireless Access (MBWA)". Official web site. Retrieved August 20, 2011

17.  "the way to new energy". ITER. 2011-11-04. Retrieved 2011-11-08.
 "Electron Cyclotron Resonance Heating (ECRH)". Ipp.mpg.de. Retrieved
 Raytheon's Silent Guardian millimeter wave weapon
"eEngineer – Radio Frequency Band Designations". Radioing.com. Retrieved
PC Mojo – Webs with MOJO from Cave Creek, AZ ( ). "Frequency Letter bands – Microwave Encyclopedia". Microwaves101.com. Retrieved

18. Merrill I. Skolnik, Introduction to Radar Systems, Third Ed
 Merrill I. Skolnik, Introduction to Radar Systems, Third Ed., Page 522, McGraw Hill,
Goldsmith, JR (December 1997). "Epidemiologic evidence relevant to radar (microwave) effects". Environmental Health Perspectives 105 (Suppl. 6): 1579– 1587. doi: / JSTOR   PMC
 PMID 
Philip L. Stocklin, US Patent 4,858,612, December 19, 1983
 "''The work of Jagdish Chandra Bose: 100years of MM-wave research'', retrieved "