Through-Wall Imaging With UWB Radar System - KEMT FEI TUKE

Chapter 2
State Of The Art
2.1 UWB Radar Systems
2.1.1 History of Radar
Christian Huelsmeyer gave public demonstrations of the use of radio echoes to
detect ships so that collisions could be avoided in Germany and the Netherlands
in 1904. System consisted of a simple spark gap aimed using a multipole antenna.
When a reflection was picked up by the two straight antennas attached to the
separate receiver, a bell sounded. The system detected the presence of ships up
to 3 km. It did not provide range information, only warning of a nearby metal
object, and would be periodically ”spun” to check for ships in bad weather. He
patented the device, called the telemobiloscope, but due to lack of interest by the
naval authorities the invention was not given into production [16]. Nikola Tesla
proposed principles regarding frequency and power levels for primitive radar units
in August 1917. Tesla proposed the use of standing electromagnetic waves along
with pulsed reflected surface waves to determine the relative position, speed, and
course of a moving object and other modern concepts of radar [94]. The World War
II moved forward developing of airborne radars [22]. The next major development
in the history of radars was the invention of the cavity magnetron by John Randall
and Harry Boot of Birmingham University in early 1940’s. This was a small device
which generated microwave frequencies much more efficiently. The UWB term was
at first used in the late 1960’s Harmuth at Catholic University of America, Ross
and Robbins at Sperry Rand Corporation and Paul van Etten at the USAF’s
Rome Air Development Center [13]. Till the end of 20th century there were lot
of radar types for different applications like airborne radars, ground penetrating
radars, sonars, and one which will be discussed further in detail the through-wall
penetrating radar.
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