Multi-dimensional signal processing and circuits for advanced electronically scanned antenna arrays

Highly directional receive mode beamforming is a crucial signal processing task encountered in modern smart antenna array technology. Especially, signal processing techniques to support multiple ultra-wideband (UWB) radio frequency (RF) beams at lower computational complexity are of signicant interest in a wide range of applications including radar, RF sensing, imaging, wireless communications, and major science instrumentation projects. This doctoral dissertation discusses recent advancements in multidimensional (MD) space-time signal processing algorithms and circuits for electronically scanned smart antenna array receive mode beamforming. The proposed MD signal processing models exploit planar-resonant properties of MD passive prototype networks to design MD space-time filters with infinite impulse response (IIR) at guaranteed filter stability. The beamforming problem is analyzed in a MD signal processing perspective to proposed novel MD signal processing models and massively parallel digital circuits to support multi-beam linear aperture arrays. Closed-form design equations are provided, which relate MD filter design parameters to beam personalities in the array pattern. A quantitative comparison of three-dimensional (3-D) IIR cone filters with conventional phased array beamformers is performed to show that the 3-D IIR cone filters provide frequency independent beam selectivity at an order of magnitude lower multiplier circuit complexity in a typical digital hardware implementation. Application of MD signal processing concepts in cognitive radio (CR) networks is discussed and a low-complexity array processing scheme to detect space-time spectral white-spaces in MD frequency domain is proposed. Digital hardware realizations as well as continuous-time domain analog realizations of selected algorithms are presented. A novel technique based on first-order all-pass filters is proposed towards the realization of linear array beamforming methods at multi-GHz frequencies. Signal processing models and proof-of-concept simulation examples are provided for a novel beamforming technique to produce highly-selective closely-packed multiple hexagonal beams with potential applications in high-precision volume scans and imaging. Application of MD IIR plane-wave filters in conventional phased/timed array beamforming systems to significantly enhance the interference rejection capability is discussed with preliminary system-level simulations.