Distributed Array Transmitter Spatial Coherence in Active Incoherent Millimeter-Wave Imaging

We present measurements and analysis of the transmit pattern spatial coherence in active incoherent millimeter-wave imaging systems. Incoherent microwave and millimeter-wave imaging systems have recently attracted research interest due to their ability to generate imagery with reduced hardware requirements compared to coherent systems like phased arrays. Unlike traditional coherent systems and computational imaging where the knowledge of transmit radiation is very important, a newly-developed active incoherent millimeter-wave imaging does not require explicit knowledge of the transmit waveform, provided that the spatial coherence between points in the scene is sufficiently low. In this paper, we introduce a simple measurement to quantify the spatial coherence of waveform impinging on the scene. We present the basic theory and experimental results of the transmission of two noise transmitters.