A New Digital Receiver Architecture For Direction Finding Systems

We propose in this paper a simple receiver structure in which the radio frequency signal is directly digitized by the analog-to-digital converters (ADC) with a sampling frequency smaller than signal frequency. This structure is used for direction finding system by means of an antenna array. The direction of arrival (DOA) of RF signal is estimated using the proposed receiver architecture and the high resolution method MUSIC (multiple signal classification). The measurement system composed of a 4 quasi-Yagi antenna element uniform linear array and of 4 parallel digital receivers using a digital oscilloscope is built for validating this idea. The simulation results using ADS (Advanced Design System) software and the measurement results in anechoic chamber show that the DOA is accurately determined by this structure.