초록 ▼

Vertical surface protection in a security installation is achieved by detecting disturbances in a microwave beam sent from a transmitter to a receiver, both installed substantially above the ground and adjacent to the vertical surface. The transmitter and receiver have associated beam aerials of ext

Vertical surface protection in a security installation is achieved by detecting disturbances in a microwave beam sent from a transmitter to a receiver, both installed substantially above the ground and adjacent to the vertical surface. The transmitter and receiver have associated beam aerials of extended horizontal aperture of not less than 0.50 meters (20 inches) to mitigate the effects of surface reflection from metal scaffold, plastic sheeting or netting, wooden boarding and brick or stone facing. The aerials are preferably slotted waveguide arrays and the advantages of using circular polarization are shown. Circularly-polarized slotted waveguide arrays are disclosed having a center feed to minimize frequency-dependent beam-spreading. The sensor may be used with an intruder detector to protect buildings in scaffold by utilizing triple technology exterior detection incorporating: microwave Doppler shift; at least one and preferably two passive infra-red devices linked together through timers and lens with horizontal curtain pattern; and anti-sabotage reflected active infra-red. The system can combine the aforementioned technologies into a new device and this format overcomes the individual limitations of each of the prior art technologies when used in unison in an external scaffold environment.

대표청구항 ▼

[ What is claimed is:] [1.] A security system installed adjacent a vertical surface for detecting the presence of an intruder climbing through a path adjacent the vertical surface, the system having:a microwave transmitting station comprising:a transmitting aerial positioned at one end region of sai

[ What is claimed is:] [1.] A security system installed adjacent a vertical surface for detecting the presence of an intruder climbing through a path adjacent the vertical surface, the system having:a microwave transmitting station comprising:a transmitting aerial positioned at one end region of said path and having an aerial aperture which has an extent in a direction substantially at right angles to said vertical surface of not less than 0.50 meters (20 inches) to provide a substantially planar microwave beam pattern having an extent at right angles to said path which has a direction a major component of which is horizontal; anda microwave receiving station comprising:a receiving aerial positioned at an opposite end region of said path and having an aerial aperture which has an extent in a direction substantially at right angles to said vertical surface of not less than 0.50 meters (20 inches) to receive said microwave beam pattern;a microwave receiver coupled to receive microwave radiation received by said receiving aerial and having means responsive to variation of the received radiation outside a given range to produce a signal to represent the presence of an intruder climbing through said path; andsaid system including arrangements for directing said microwave beam in a directional pattern substantially elevated above the ground;whereby intruders climbing through or entering said pattern are detected, and objects moving along the ground do not trigger the security system.