UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
5-4.3.1 Monostatic. Monostatic microwave sensors use a single sensing unit that
incorporates both transmitting and receiving functions. Many monostatic microwave
sensors feature a cut-off circuit, which allows the sensor to be tuned to only cover within
a selected region. This helps to reduce nuisance alarms. Refer to Figure 5-7 for
illustrations of a monostatic microwave sensor and associated footprints.
Figure 5-7. Monostatic Microwave Sensor and Associated Footprints
5-4.3.2 Bi-static. Bi-static microwave sensors are more commonly used than
monostatic sensors for wide-area surveillance. Bi-static microwave sensors use a
transmitter and receiver pair. Bi-static sensors work over longer distances than mono-
static sensors. Typical distances for transmitter-receiver pairs are ten to six hundred
feet for X-band frequencies and one hundred to fifteen hundred feet for Y-band
frequencies. The bi-static transmitter typically sends out a high frequency open-band
radio frequency in a 3-8 degree pattern. (Common microwave frequencies are X-band
10 GHz or Y-band 24 GHz.) Refer to Figure 5-8 and Figure 5-9 (next page) for
illustrations of bistatic microwave sensor operation.
5-4.3.3
Microwave Design Guidance and Recommendations
5-4.3.3.1 The detection zone should be free of bushes and obstructions.
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