Method of detecting intruders and intruder detection apparatus of the capacity-type utilizing balanced asymmetric fields

Claim 1

THE METHOD OF ELECTRICALLY PROTECTING A BOUNDARY AND DETECTING THE APPROACH OF AN INTRUDER THERETO, COMPRISING THE STEPS OF GENERATING FIRST AND SECOND RADIO FREQUENCY OSCILLATIONS, RADIATING A PORTION OF THE ENERGY OF SAID FIRST OSCIALLATION ALONG SAID BOUNDARY TO ESTABLISH A FIRST ELECTROMAGNETIC FIELD EXTENDING ALONG SAID BOUNDARY IN ONE DIRECTION FROM AN INTERMEDIATE POINT, RADIATING A PORTION OF THE ENERGY OF SAID SECOND OSCILLATION ALONG SAID BOUNDARY TO ESTABLISH A SECOND ELECTROMAGNETIC FIELD EXTENDING ALONG SAID BOUNDARY IN THE OTHER DIRECTION FROM SAID INTERMEDIATE POINT, SAID ELECTROMAGNETIC FIELDS BEING ASYMMETRIC WITH RESPECT TO EACH OTHER IN A DIRECTION NORMAL TO SAID BOUNDARY BUT BEING SUBSTANTIALLY BALANCED IN A DIRECTION PARALLEL TO SAID BOUNDARY, VARYING THE FREQUENCY OF EITHER OF SAID OSCILLATIONS IN RESPONSE TO THE ENTRY OF AN INTRUDER INTO THE CORRESPONDING ONE OF SAID ELECTROMAGNETIC FIELDS, AND PRODUCING AN ALARM SIGNAL IN RESPONSE TO AT LEAST A MINIMUM VARIATION IN THE RATIO BETWEEN THE FREQUENCIES OF SAID OSCILLATIONS, SAID ASYMMETRY OF SAID FIELDS BEING SUFFICIENT SO THAT SIMULTANEOUS AND COORDINATED APPROACH OF TWO INTRUDERS TO CORRESPONDING POINTS OF SAID BOUNDARY ON OPPOSITE SIDES OF SAID INTERMEDIATE POINT DO NOT PRODUCE EFFECTS ON THE FREQUENCIES OF SAID OSCILLATIONS WHICH ARE SUFFICIENTLY SIMILAR AS TO PREVENT PRODUCTION OF AN ALARM SIGNAL.

Claim 2

THE METHOD OF ELECTRICALLY PROTECTING A BOUNDARY AND DETECTING THE APPROACH OF AN INTRUDER THERETO, COMPRISING THE STEPS OF GENERATING FIRST AND SECOND RADIO FREQUENCY OSCILLATIONS, RADIATING A PORTION OF THE ENERGY OF SAID FIRST OSCIALLATION ALONG SAID BOUNDARY TO ESTABLISH A FIRST ELECTROMAGNETIC FIELD EXTENDING ALONG SAID BOUNDARY IN ONE DIRECTION FROM AN INTERMEDIATE POINT, RADIATING A PORTION OF THE ENERGY OF SAID SECOND OSCILLATION ALONG SAID BOUNDARY TO ESTABLISH A SECOND ELECTROMAGNETIC FIELD EXTENDING ALONG SAID BOUNDARY IN THE OTHER DIRECTION FROM SAID INTERMEDIATE POINT, SAID ELECTROMAGNETIC FIELDS BEING ASYMMETRIC WITH RESPECT TO EACH OTHER IN A DIRECTION NORMAL TO SAID BOUNDARY BUT BEING SUBSTANTIALLY BALANCED IN A DIRECTION PARALLEL TO SAID BOUNDARY, VARYING THE FREQUENCY OF EITHER OF SAID OSCILLATIONS IN RESPONSE TO THE ENTRY OF AN INTRUDER INTO THE CORRESPONDING ONE OF SAID ELECTROMAGNETIC FIELDS, AND PRODUCING AN ALARM SIGNAL IN RESPONSE TO AT LEAST A MINIMUM VARIATION IN THE RATIO BETWEEN THE FREQUENCIES OF SAID OSCILLATIONS, SAID ASYMMETRY OF SAID FIELDS BEING SUFFICIENT SO THAT SIMULTANEOUS AND COORDINATED APPROACH OF TWO INTRUDERS TO CORRESPONDING POINTS OF SAID BOUNDARY ON OPPOSITE SIDES OF SAID INTERMEDIATE POINT DO NOT PRODUCE EFFECTS ON THE FREQUENCIES OF SAID OSCILLATIONS WHICH ARE SUFFICIENTLY SIMILAR AS TO PREVENT PRODUCTION OF AN ALARM SIGNAL.