Poster 1.2
A Spectrally Clean Transmitting System for Solid-State Phased-Array Radars

Hugh H Faust - Naval Research Laboratory

Tue, 27 April 2004, 9:30 AM - 10:20 AM

Abstract

Navy Radar operations are being curtailed in a littoral environment. This is due to two factors: The encroachment of the cell phone systems into the Navy radar bands and in-band interference from other radars. The Spectral width of most pulsed radars is significantly wider than necessary with the present modulation schemes. Most radars utilize some form of constant envelope pulse with phase or frequency modulation. This causes the spectrum to broaden several times the information bandwidth. If both the amplitude and phase of the transmitted signal are allowed to change a significantly narrower bandwidth can be achieved. In this paper a method to create waveforms with instantaneous bandwidths of 20 MHz confined within ?100 dB are presented. The theoretical spectral results of three popular phase modulation schemes (phase shift keying, minimum phase shift keying, and derivative phase shift keying) are compared with the spectrally clean results. In addition the Chireix out-phasing method is presented as an alternative to generating amplitude and phase modulated waveforms. The Chireix method provides a way of improving the efficiency compared to the conventional class A power amplifier. Preliminary results are shown for a spectrally clean waveform.

Bio

Mr. Faust received his B.S. (1972) and M.S. (1973) in Electrical Engineering from George Washington University. Further postgraduate work was done at the University of Maryland until 1975 when Mr. Faust began work at the Naval research Laboratory. Mr. Faust started in Target Characteristics branch of Radar Division where he worked on the development of aircraft landing sensors for the Marines. He has worked on non-cooperative target identification using radar since 1980 in Doppler Techniques section in which he contributed to the development of radar ID systems on air and ground platforms. He developed the signal processing for the SPN-43C ADM Doppler processor upgrade. In addition he developed the signal processing for the NATO Seasparrow missile system signal data processor (SDP) upgrade. Mr. Faust presently is working on BMD radar receiver technology improvements, including spectrally clean waveforms.