ENVIRONMENTAL AND PROPAGATION FACTORS AFFECTING THE PERFORMANCE OF X AND K-BAND MICROWAVE SENSORS

Microwave sensors have been widely used in perimeter intrusion systems for many years. While the performance and application of microwave sen- sors for perimeter security systems has been well documented, the effects of climatic and other environmental factors appear to be less publi- cized. Microwave sensors have been designed to operate at various frequencies from UHF to 94 GHz, however, the majority of sensors now in use op- erate at either 10.525 or 24.125 GHz. This paper will examine the role of frequency in maintaining specified performance in the presence of various environmental conditions. Rain, snow, lightning, and manmade interference can contribute to false alarms or impair the sensor performance. Fre- quency is an important sensor design parameter that can be used to control climatic and EMI prob- lems and it can also be used to solve specific application problems. A recent trend in the de- sign of security systems is to use both X and K- band sensors for improved reliability and enhanced vertical coverage.