Microwave engineering is the one of the part of electronics engineering

1. Microwave and Optical Communication Laboratory
INSTRUCTION CLASS

2. Microwave
• Microwave are the Electromagnectic Waves whose frequency range
from about 300MHz-300GHz or wavelength in air ranging from
100cm-1mm
• The word Microwave means very short wave, which is the shortest
wavelength region of the radio spectrum and a part of electromagnetic
spectrum

3. Raul's Mother Is Visiting Uncle Xavier's Garden
R- Radio M- Microwaves I- Infrared V- Visible U- Ultraviolet X- X-Rays G-
Gamma Rays
Electromagnetic Spectrum

4. Microwave Frequency bands
(LSCXKUKKA)

5. Applications
• Wireless Communications
• Commercial Uses
• Burglar alarms, Garage door openers, Police speed detectors, Identification by non-contact
methods, Cell phones, pagers, wireless LANs, Satellite television, XM radio, Motion detectors,
Remote sensing
• Navigation
• Military and Radar
• Radars to detect the range and speed of the target, SONAR applications, Air traffic control, Weather
forecasting, Navigation of ships, Minesweeping applications, Speed limit enforcement, Military
uses microwave frequencies for communications and for the above mentioned applications.
• Research Applications
• Atomic resonances
• Nuclear resonances
• Food Industry
• Industrial Uses
• Semiconductor Processing Techniques
• Medical Applications

6. Sources of microwave
• Low power microwave sources use solid-state devices such as the
Field-effect Transistor(at least at low frequencies),Tunnel Diodes,
Gunn Diodes
• High power microwave sources used specialized vacuum tubes to
generate microwaves. These devices operate on different principles
from low frequency vacuum tubes, using the ballistic motion of
electrons in a vacuum under the influence of controlling electric or
magnetic fields, and include the Magnetron, Klystron, Travelling
Wave Tube(TWT) and Gyrotron.

7. Microwave Components
• Microwave Transistors
• Varactor Diode
• Schottky Barrier Diode
• Gunn Effect Devices
• IMPATT Diode
• TRAPATT Diode
• BARITT Diode
• Monolithic Microwave Integrated Circuit MMIC

8. Waveguide
• A hollow metallic tube of uniform cross section for transmitting
electromagnetic waves by successive reflections from the inner walls
of the tube is called waveguide.

9. Types of Waveguides
There are five types of waveguides.
1. Rectangular waveguide
2. Circular waveguide
3. Elliptical waveguide
4. Single-ridged waveguide
5. Double-ridged waveguide

10. Modes of propagation
• There are three modes that can propagate in the
waveguides:
• TE mode: This waveguide mode is dependent
upon the Transverse Electric waves, also
sometimes called H waves, characterized by the
fact that the electric vector (E) being always
perpendicular to the direction of propagation.
• TM mode: Transverse magnetic waves, also
called E waves are characterized by the fact that
the magnetic vector (H vector) is always
perpendicular to the direction of propagation.
• TEM mode: The Transverse electromagnetic
wave cannot be propagated within a waveguide. It
is the mode that is commonly used within coaxial
and open wire feeders. The TEM wave is
characterized by the fact that both the electric
vector (E vector) and the magnetic vector (H
vector) are perpendicular to the direction of
propagation.

11. MICROWAVE SYSTEM
 A microwave system normally consists of a transmitter subsystems, including a microwave oscillator, wave guides
and a transmitting antenna, and a receiver subsystem that includes a receiving antenna, transmission line or wave
guide, a microwave amplifier, and a receiver.
 Reflex Klystron, Gunn Diode, Traveling Wave Tube, and Magnetron are used as a microwave sources.
 Isolators provide low attenuation for the forward direction and high attenuation for reverse direction to avoid
reflected power.
 A variable attenuator is a circuit that decreases the strength of the input signal either continuously or step by step
without appreciable signal distortion.
 Frequency meters, also called "wavemeters", used to determine the frequency of an unknown signal source.
 The slotted measuring line consists of a slotted line and a movable platform with measurement probe, which is
inserted into the waveguide to sample the field. The detector is required to detect the microwave signal.

12. Optical Frequency Range
The optical spectrum is generally defined to encompass
electromagnetic radiation with wavelengths in the range from
10 nm to 103 μm, or frequencies in the range from 300 GHz
to 3000 THz