TDU quantization error impact on wideband phased-array performance

Large, wideband phased-array antennas typically employ a time-delay subarray architecture to support wideband waveforms. Previous work has documented the need to appropriately size the subarrays to minimize scan angle dependent dispersion loss and preserve range resolution. However, practical issues associated with the subarray time-delay units (TDU) also limit performance. Typically, TDU are digitally addressed binary devices with a minimum resolution defined by the least significant bit (LSB) size (measured in time, typically nanoseconds, or path length). This paper discusses losses-in both signal-to-noise ratio (SNR) and range resolution-due to subarray to subarray time delay offsets resulting from TDU quantization errors. Simulation results are presented for wideband LFM waveforms.