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The aim of our research is to design surrogate test targets for evaluation of automotive Pre-Collision Systems (PCS).To design these surrogate test targets, we used derived scattering sources from measured radar returns of selected subject vehicles. Twenty-five vehicles were selected from a broad range of vehicle classes. This group includes several vehicles that are frequently struck in rear-end collisions as determined by the U.S. National Crash Database [1]. We used a wideband, millimeter wave, instrumentation radar to measure radar returns of these subject vehicles. Range profiles and real-beam images were used to isolate scattering sources, which were then used to design surrogate targets that mimic the radar response of real cars. To verify the design of such surrogate test targets, we developed and applied a statistical model [2] of radar signatures from the group of selected vehicles at a fixed set of viewing angles. The collected signatures for each vehicle and test-surrogates were fit to a Weibull-distribution using a maximum-likelihood estimator. We then applied results of the statistical studies to evaluate the surrogate test targets.

2 versions of a compact multi-beam dualfrequency antenna for 24 and 77 GHz have been developed for automotive applications. The antenna consists of a spherical Teflon lens with a frequency selective surface (FSS), which is fed by two sets of endfire tapered slot antennas (TSAs). The FSS is built on a 127 µm-thick Duroid TM substrate and is placed between two Teflon hemispheres, and is reflective at 24 GHz and transparent at 77 GHz in the first design, and is transparent at 24 GHz and reflective at 77 GHz in the second design. The TSAs for the 24 GHz and 77 GHz systems are built on a single piece of 254 µm-thick Duroid TM substrate. The measured patterns result in E and H-plane patterns with a −3-dB beamwidth of 19 • at 24 GHz and 5.5 • at 77 GHz. The sidelobe level is better than −17 to −20 dB when the FSS is transparent and is better than −14 dB when the FSS is reflective. The calculated efficiency of this antenna system is around 50%. The current designs provide 33 • coverage at 24 GHz (3 beams) and 55 • coverage at 77 GHz (11 beams) in the first design, and 99 • coverage at 24 GHz (7 beams) and 33 • coverage at 77 GHz (7 beams) in the second design, but the angles can be changed to suit different coverage angles.