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I EEE TRANSACTIONS IN INSTRUMENTATION AND MEASUREMENT, VOL. 40, NO . 4. AUGUST 1991
Automatic Clutter-Canceler for Microwave
Huey-Ru Chuang, Member, IEEE, Y. -F. Chen, and Kun-Mu Chen, Fellow, IEEE
Abstract-A microprocessor-controlled automatic cluttercancellation subsystem, consisting of a programmable micro wave attenuator and a programmable microwave phase-shifter controlled with a microprocessor-based control unit, continues to be developed for any microwave life-detection system (L-band 2 GHz or perhaps X-band 10 GHz) which could remotely perception breathing and
heartbeat motions of living subjects. This kind of automatic cluttercancellation subsystem features drastically superior a very slow p~ocess. of manual clutter-cancellation adjustment in our preVIOU. H mlcro~av. e sys~em. ~his is very important for some potential applications mcludmg site of earthquake or avalanche-trapped victims through rubble. Several experiments have been completely conducted to demonstrate the use of this micro wave life-detection system for rescue purposes. The automatic clutter-canceler may also have a potential program in some CW radar devices.
ECENTLY a microwave life-detection system
(L-band 2 GHz or X-band 12 GHz) has been developed - to slightly detect the breathing and heartbeat signals of human topics lying in the grass at a 100-ft distance, or located behind a barrier wall structure. The basic rule of the method is to illuminate the human subject
which has a low-intensity microwave beam so that the small
amplitude body-vibrations as a result of breathing and heartbeat from the human subject will regulate the backscattered microwave sign. The breathing and heartbeat alerts can
always be extracted using this backscattered transmission by phase-detection in the micro wave receiving program. A potential application of this system is always to locate living
human subject matter buried in rubble after an earthquake or
increase by slightly detecting inhale and heartbeat
movements throughout the barrier (Fig, 1). To be able to maintain a top sensitivity with this application, the clutter wave reflected from your rubble or perhaps the surface in the ground features
to be cancelled as thoroughly as possible before it gets to
and saturates the receiving microwave augmenter. In our
earlier system, the clutter termination was performed
by a very slow manual-adjustment process. This is not
easy for a actual emergency save operation
which demands a quick process. Through this paper, all of us present
a newly produced automatic clutter-cancellation subsys-
Manuscript received June 6th. 1990: modified March six. 1991.
Con. -F. Chen and E. -M. Chen are while using Department of Electrical Engineering and Systems Science. The state of michigan State College or university. East Lansing. MI48824.
L. -R. Chuang is with the Department of Electrical Engineering. National Cheng Kung College or university. Tainan, Taiwan. Republic of China. IEEE Log Amount 9100365.
Fig. We. Rescue putting on the micro wave life-detection program.
tem using a microprocessor-based control unit designed
to control a programmable micro wave attenuator and a
programmable microwave phase-shifter for doing the
real-time automatic clutter-cancellation. The basic principle of this subsystem is to use the microprocessor-based control unit in diagnosing the attenuator and phase-shifter to
minimize the input signal for the microwave amplifier and
consequently cancel the clutter aspect.
A series of trials has been executed to evaluate
the breathing and heart indicators of a human being subject through
a split pile of bricks simulating rubble. It absolutely was found
which the performance of the X-band (10 GHz) program became minor when the brick structure surpassed about 1 . 5 foot in thickness (about 5 levels of bricks), while for the L-band (2 GHz) system it was conceivable to sink into a load
of dried rubble as high as about several ft thick (about 10
layers of bricks). This suggests that a reduced frequency
could be more...
References: Lansing, MI, 1984.
[4) K. -M. Chen, L. -R. Chuang, and Yo-F. Chen, " Microprocessor-controlled micro wave life recognition system, " Technical Representative., Electromagnetics Lab, Department of Electrical Executive and Systems Science, Michigan State College or university, 1988.
Orleans, LA, November. 1988.
Compat., vol. 23, pp. 330-332, Aug. 1989.