Design and Testing of an Interference Modulator for DEW Applications

The interference modulator (IM) is a microwave source concept that can produce a broadband, amplitude modulated radio frequency (rf) waveform with independently tunable carrier and modulation frequencies. In its simplest form, the IM is a two-channel device that can produce an amplitude modulated signal at 50-percent duty by either generating and beating two electromagnetic waves together in the far field or by combining the two signals with a four-port hybrid network. With additional channels, an IM can be made to synthesize more complex waveforms and duty factors. A general methodology for the design of an n-channel (n > 2) IM is developed. As a validation of the design methodology, a two-channel prototype lM was constructed. The design, fabrication, and testing of the two-channel prototype are described in detail. Experiments carried out with the prototype IM have successfully demonstrated the IM concept, producing a source with a modulation envelope that is continuously tunable over four decades (from 100 Hz to 1 MHz), with a carrier frequency that is continuously tunable from 800 MHz to 2 GHz.Army Research Lab Adelphi is the author of 'Design and Testing of an Interference Modulator for DEW Applications' with ISBN 9781423585329 and ISBN 1423585321.