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Time-delay multiplexing is a method where the frame rate of a single-transceiver terahertz imaging
radar can be doubled by splitting the transmitted beam into two beams of orthogonal polarization,
and then scanning the beams over two separate regions of a target simultaneously. We previously
demonstrated multiplexing at 4 m standoff distances in a 670 GHz imaging radar, using waveguide
components to split the beams rotate their polarization. However, significant ohmic losses through
the waveguide components were measured, and finite transmit/receive coupling contributed to a
substantial dynamic range reduction. In this contribution we demonstrate radar multiplexing in
a 670 GHz imaging radar operating at longer standoff distances of 25 m, and we present an
all-quasioptical approach for beam splitting and polarization rotation. By eliminating the
extra waveguide components, we have achieved a frame rate doubling from 0.5 to 1 Hz with
negligible signal attenuation or leakage.
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