advances facilitating reliable high-capacity data rates are allowing wireless (microwave) backhaul to
maintain its position as a competitive alternative to fiber in mobile radio
access networks (RANs). The traditional strengths of short deployment times,
reliability and flexibility have been complimented by improvements in spectrum
efficiency and the introduction of scalable
IP/Ethernet radio and adaptive modulation.
frequency spectrum in the millimeter wave bands is also available, enabling
short range multi-gigabit transmission from much wider channels using robust
low level modulations. The associated antenna systems have also been undergoing
significant evolution. Engineers have made important
developments which are benefiting the operators, enabling them to manage
their valuable spectrum more efficiently, by achieving higher system capacity,
greater reliability, and reduced CapEx/OpEx
microwave systems use directive antennas to focus radio signals like a beam of light and
transmit them over line-of-sight distances. As a result, microwave radio
represents a highly effective means of providing long distance service,
especially over areas with difficult terrain where the installation of cable is
economically or technically impractical.
microwave systems have assumed a position of considerable importance in the telecommunication
understand why, let’s take a look at some early
examples of long-distance communications and how microwave emerged as a
The first attempts at
communication over distances were extremely limited. Early man relied on fire and
smoke signals to encode information over limited geographic areas. Centuries
later, the Gutenberg printing press with a moveable typeface was developed. This revolutionized the mass
production of written communication.
The optical telegraph (aka
semaphore telegraph) was invented in 1792 and provided a more complex form of long
distance communication. In the 19th and 20th centuries,
communication systems evolved into the electrical era with the telegraph system.
This evolution then led to the introduction of the telephone and television.
Hertz proved the existence of
radio waves in 1887. He used two rods to serve as a receiver and a spark gap as
the receiving antenna. Where the waves were picked up, a spark would jump.
Hertz showed in his experiments that these signals possessed all of the
properties of electromagnetic waves as theorized by James Clerk
Maxwell, known to most engineers and physicists as “Maxwell’s
The first formal use of microwave was a relay across the English
Channel in 1931. Data was transmitted over a bidirectional 1.7 gigahertz link,
64 kilometers between Dover, UK and Calais, France. By the late 1940s and early
1950s, microwave relay systems began to play a prominent role in
communications. In 1976, the first digital microwave radio was
To support the higher data rates required for
connecting 3G cell sites to the network, there was a lot of pressure on
microwave equipment vendors to push the envelope. In 2008, the development of adaptive modulation radio enabled a
microwave link to vary its data rate according to the atmospheric conditions. To
address consumer’s ever increasing appetite for data today, microwave radio vendors continue to
create radios with more complex modulation schemes.
in learning more about the design and licensing of point-to-point microwave
communication systems? The SP6700
Microwave Path Engineering Fundamentals course
has been developed by Comsearch.
in microwave design and frequency engineering have helped to design more than
200,000 microwave paths since 1977.