DIAGNOSTIC TOOL FOR HIGH POWER MICROWAVE (HPM)

THE ACCURATE MEASUREMENT OF ELECTRIC FIELD PULSE SHAPE AND INTENSITY IS OFTEN DIFFICULT DUE TO THE PERTURBING EFFECT OF THE MEASUREMENT ANTENNA ITSELF AND THE ASSOCIATED CABLE. PREVIOUS ATTEMPTS TO MINIMIZE THESE EFFECTS HAVE RESULTED IN THE DEVELOPMENT OF ELECTROMAGNETIC PROBES USING METALLIC ANTENNAS THAT DO NOT DIRECTLY REVEAL PULSE OR CW SIGNAL SHAPE, BUT RATHER TRANSMIT A DC REPRESENTATION OF SIGNAL STRENGTH. OTHER APPROACHES USING FIBER OPTICS HAVE NOT ELIMINATED METAL COMPONENTS AND HAVE LACKED ADEQUATE BANDWIDTH. HOWEVER, NEW DEVELOPMENTS IN LASERS AND FIBER OPTICS HAVE MADE POSSIBLE THE DESIGN OF ALL OPTICAL APPROACHES TO ELECTROMAGNETIC FIELD MEASUREMENT THAT PROMISE GREATLY IMPROVED ACCURACY BY ELIMINATING ALL METAL FROM THE FIELD SENSOR AND THE ASSOCIATED CABLES. A NEW MODULATOR DESIGN USING SINGLE MODE OPTICAL FIBERS AND A MINIATURE LITAO(3) CRYSTAL IS CAPABLE OF SENSING HIGH POWER MICROWAVE (HPM) PULSE WITH POWER LEVELS BETWEEN 10 AND 1000 W/CM(2) FOR FREQUENCIES UP TO AT LEAST 10 GHZ. IN ADDITION, THE FIBER OPTIC APPROACH PROVIDES FOR THE TRANSMISSION OF THE ACTUAL SIGNAL TO REMOTE ELECTRONICS FOR ANALYSIS AND MEASUREMENT. THUS PULSE SHAPE AND OTHER PARAMETERS CAN BE ANALYZED IN DETAIL.