MICROWAVE/MILLIMETER-WAVE FIELD SENSOR

THE ACCURATE MEASUREMENT OF ELECTROMAGNETIC FIELDS IS OFTEN COMPLICATED BY THE INTERACTION BETWEEN THE FIELD BEING MEASURED AND THE RECEIVING ANTENNA WITH ITS ASSOCIATED ELECTRONICS AND CABLING. WITH THE DEVELOPMENT OF HIGH FREQUENCY FIBER OPTIC ANALOG LINKS, OPTICAL CABLES HAVE BEEN USED TO ISOLATE THE MEASUREMENT ANTENNA. HOWEVER, PREVIOUS EFFORTS HAVE HAD THE DISADVANTAGE OF REQUIRING A RELATIVELY LARGE PHYSICAL VOLUME AT THE ANTENNA LOCATION, WHICH PERTURBS THE FIELD BEING MEASURED. IN ORDER TO OVERCOME THIS PROBLEM, TACAN HAS RECENTLY DEVELOPED AND TESTED A NEW APPROACH FOR HIGH FREQUENCY FIELD MEASUREMENTS USING REMOTE OPTICAL POWERING TO ELIMINATE BATTERY OPERATION OF THE ELECTRONICS AND ELECTRO-OPTICS. A SPECIAL ELECTRO-OPTIC INTERFACE HAS BEEN DESIGNED, CONSISTING OF PASSIVE ELECTRICAL COMPONENTS TO COMPLETE A BIAS TEE NETWORK AND PROVIDE IMPEDANCE MATCHING. THE TOTAL VOLUME FOR THE ELECTRO-OPTIC INTERFACE UNIT CAN BE LESS THAN 1 CM3. NO BATTERIES ARE REQUIRED, AND THEREFORE OPERATION IS CONTINUOUS WITHOUT INTERRUPTIONS FOR BATTERY REPLACEMENT. NEW TECHNIQUES ARE DESCRIBED TO EXTEND THE FREQUENCY RESPONSE TO 100 GHZ. THE ACCURATE MEASUREMENT OF ELECTROMAGNETIC FIELDS WOULD BENEFIT A WIDE VARIETY OF COMMERCIAL APPLICATIONS, INCLUDING ANTENNA DEVELOPMENT, MONITORING OF ELECTROMAGNETIC FIELDS FOR POTENTIAL HAZARDS, AND EMI AND RFI MEASUREMENTS. COMPLETELY ACCURATE AND NON-PERTURBING MEASUREMENT TECHNIQUES HAVE NOT BEEN AVAILABLE TO DATE AND WOULD BE INVALUABLE FOR SCIENTIFIC INVESTIGATIONS.