Microwaves EE423
By
Dr Abdelhamid Albaraesi (Salem)
Elect. & Electron Engineering
University of Benghazi
Course Outline
Introduction to Microwaves.
Transmission Line Theory.
Smith Chart.
Impedance Matching.
Waveguides.
Microwave Passive Components.
Analysis of Microwave Networks.
Microwave Resonators.
Microwave Filters.
Introduction to Microwaves
Micro: Tiny (small) wavelengths (1 meter-1 mm) .
Frequency of Microwave varies from 300 M Hz to 300 G Hz.
Wavelength: λ=, for 300 M Hz: λ=.
Different sources define different frequency ranges as microwaves. In all cases,
microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1cm) at minimum.
Mw
Table 1 Frequency Band Designation.
Table 2 Microwave Frequency Band Designation.
Because of the high frequencies (and short wavelengths), standard circuit theory often cannot be
used directly to solve microwave network problems.
Standard circuit theory is an approximation, or special case, of the broader theory of
electromagnetics as described by Maxwell’s equations.
ADVANTAGES OF MICROWAVES
Large Bandwidth:
The Band width of Microwaves is larger than the common low frequency radio waves.Thus
more information can be transmitted using Microwaves.
Small Size Antenna:
The size of antenna is inversely proportional to the transmitted frequency. Thus in
Microwaves with very high frequencies, the size of antenna is small.
Microwave signals travel by line of sight and are not bent by the ionosphere as are
lower frequency signals. Satellite communication links with very high
capacities are therefore possible
Antenna gain is proportional to the electrical size of the antenna. At higher frequencies,
more antenna gain can be obtained for a given physical antenna size, and this
has important consequences when implementing microwave systems
APPLICATIONS OF MICROWAVES
The main application areas of Microwaves:
wireless networking and communications systems
Radar and Remote Sensing
Medical Science
Communication:
Microwaves are commonly used in communication transmissions.
The cellular networks use Microwave frequencies for communication.
Satellite systems also depend on Microwave technology.
Military or Army also uses Microwaves in their communication system.
Radar and Remote Sensing:
The most common application of Microwave is in RADAR systems.
Medical Science:
Microwave properties are also used in Medical Science.
