PASSIVE CHAFF, COMPOSED OF HALF WAVELENGTH STRIPS, TENDS TO SLOW DOWN UPON REENTRY INTO THE ATMOSPHERE, LEADING TO A DOPPLER SHIFT FROM THE TARGET SIGNAL.

PASSIVE CHAFF, COMPOSED OF HALF WAVELENGTH STRIPS, TENDS TO SLOW DOWN UPON REENTRY INTO THE ATMOSPHERE, LEADING TO A DOPPLER SHIFT FROM THE TARGET SIGNAL. TARGETS CAN THUS BE DETECTED BY RADARS THROUGH DOPPLER DISCRIMINATION AND THE CHAFF EFFECTIVENESS IS SUBSTANTIALLY REDUCED. ACTIVE CHAFF MAINTAINS ITS EFFECTIVENESS BY SPREADING ITS SIGNAL RETURN OVER A WIDER SPECTRAL BANDWIDTH THROUGH RADAR CROSS SECTION MODULATION OF INDIVIDUAL CHAFF STRIPS. THE TARGET RADAR RETURN IS THUS KEPT HIDDEN IN THE JAMMING SIGNAL SPECTRUM. THE PROPOSAL OUTLINES SOME APPROACHES TO ACHIEVE THIS EFFECT THROUGH DYNAMIC ACTIVE TERMINATION OF THE DIPOLES. THE CHARACTERISTICS OF CHAFF CLOUD RADAR RETURNS ARE DISCUSSED AND USED TO DETERMINE THE JAMMING SPECTRAL REQUIREMENTS. SEVERAL ALTERNATIVES ARE ANALYZED, INCLUDING MAKE-BREAK, VARIABLE REACTANCE LOADS AND TUNNEL DIODE-BASED ACTIVE CIRCUITS. PRACTICAL ISSUES INCLUDING POWER SOURCES, PACKAGING AND MEANS OF ACTIVATION ARE DISCUSSED IN DETAIL, TAKING INTO CONSIDERATION THE ANTICIPATED DEPLOYMENT ENVIRONMENT.