Antennas and Wave
Propagation
Dr. Saad Wasmi Osman Luhaib
Syllabus
➢Basic characteristic of antennas.
➢Linear wire antennas.
➢Ground effects on Radiation from linear antennas.
➢ loop antennas.
➢Arrays (linear, planar).
➢Broadband antennas.
➢Aperture antennas (Microstrip antennas, Horns).
➢Principles of propagation
❖ Ground wave propagation.
❖Troposphere wave propagation
❖Ionosphere wave propagation.
Content
• Introduction
• Types of antennas
• Radiation mechanism
• Current distribution on a thin wire antenna
Introduction
• An antenna is defined by Webster’s Dictionary as “a usually metallic device (as a
rod or wire) for radiating or receiving radio waves.” The IEEE Standard
Definitions of Terms for Antennas (IEEE Std 145–1983)∗ defines the antenna or
aerial as “a means for radiating or receiving radio waves.”
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Electromagnetic Waves
➢Electromagnetic waves in space are the basis of radio transmission over
great distances without direct wire connection between the transmitting and
receiving points.
➢At the transmitting and receiving stations, radio signals exist in the form of
high-frequency alternating currents in conductors and in electronic
amplifying devices.
➢Between the transmitter and receiver they exist as electromagnetic waves in
space.
➢Antennas are the devices that act as go-betweens.
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Transmitter and Receiver S
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➢The antenna converts the energy of the electrical currents into the
form of an electromagnetic field.
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of those at the transmitter
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• Radiation pattern:- A graphical representation of the radiation
properties of the antenna as a function of space coordinates.
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