Experimental Validation of On-Site Coding Digital Beamformer With Ultra-Wideband Antenna Arrays

Digital beamformers combined with ultrawideband (UWB) antennas are essential for realizing cognitive and software defined radios. Concurrently, advances in digital technology and signal processing have drastically reduced digital beamforming complexity. Recently, a novel on-site coding receiver (OSCR) architecture was proposed to significantly reduce hardware requirement for digital beamforming. Using OSCR, the signal from each antenna element is encoded, then several of these signals are grouped and digitized using a single analog-to-digital converter. Doing so, hardware requirements are drastically reduced. At the digital back-end, field programmable gate arrays are used to decorrelate and recover the signals associated with each array element for beamforming. In this paper, we demonstrate the effectiveness of the OSCR concept by building and testing a multichannel receiver using commercialoff-the-shelf components. Various test bench measurements are performed in an anechoic chamber using an UWB antenna array operating from 200 MHz-2.5 GHz, and data were collected at multiple frequencies. Results show an accurate estimate of the angle of arrival for incidence angles of θ s = 0°, 15°, 30°, and 45° away from broadside. It is verified that on-site coding has minimal or no degradation in signal-to-noise ratio.