Table of Contents

Microwave Engineering – Introduction

Electromagnetic Spectrum consists of entire range of electromagnetic radiation. Radiation is the energy that travels and spreads out as it propagates. The types of electromagnetic radiation that makes the electromagnetic spectrum is depicted in the following screenshot.

Let us now take a look at the properties of Microwaves.

Properties of Microwaves

Following are the main properties of Microwaves.

Microwaves are the waves that radiate electromagnetic energy with shorter wavelength.
Microwaves are not reflected by Ionosphere.
Microwaves travel in a straight line and are reflected by the conducting surfaces.
Microwaves are easily attenuated within shorter distances.
Microwave currents can flow through a thin layer of a cable.

Advantages of Microwaves

There are many advantages of Microwaves such as the following −

Supports larger bandwidth and hence more information is transmitted. For this reason, microwaves are used for point-to-point communications.
More antenna gain is possible.
Higher data rates are transmitted as the bandwidth is more.
Antenna size gets reduced, as the frequencies are higher.
Low power consumption as the signals are of higher frequencies.
Effect of fading gets reduced by using line of sight propagation.
Provides effective reflection area in the radar systems.
Satellite and terrestrial communications with high capacities are possible.
Low-cost miniature microwave components can be developed.
Effective spectrum usage with wide variety of applications in all available frequency ranges of operation.

Disadvantages of Microwaves

There are a few disadvantages of Microwaves such as the following −

Cost of equipment or installation cost is high.
They are hefty and occupy more space.
Electromagnetic interference may occur.
Variations in dielectric properties with temperatures may occur.
Inherent inefficiency of electric power.

Applications of Microwaves

There are a wide variety of applications for Microwaves, which are not possible for other radiations. They are −

Wireless Communications

Electronics

Fast jitter-free switches
Phase shifters
HF generation
Tuning elements
ECM/ECCM (Electronic Counter Measure) systems
Spread spectrum systems

Commercial Uses

Navigation

Global navigation satellite systems
Global Positioning System (GPS)

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

Radio Astronomy

Mark cosmic microwave background radiation
Detection of powerful waves in the universe
Detection of many radiations in the universe and earth’s atmosphere

Food Industry

Microwave ovens used for reheating and cooking
Food processing applications
Pre-heating applications
Pre-cooking
Roasting food grains/beans
Drying potato chips
Moisture levelling
Absorbing water molecules

Industrial Uses

Semiconductor Processing Techniques

Reactive ion etching
Chemical vapor deposition

Spectroscopy

Electron Paramagnetic Resonance (EPR or ESR) Spectroscopy
To know about unpaired electrons in chemicals
To know the free radicals in materials
Electron chemistry

Medical Applications

For any wave to propagate, there is the need of a medium. The transmission lines, which are of different types, are used for the propagation of Microwaves. Let us learn about them in the next chapter.

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