Narrowing the effective antenna beamwidth of a baseband radar for auto braking application

This paper describes a BAseband Radar (BAR) sensor beam-narrowing scheme for radar braking application; an early version of the BAR concept was reported previously as a precollision sensor for air-bag activation. In this paper we show how the normally wide effective beamwidth of the BAR is narrowed by using interferometry in conjunction with a novel delay line digital processor scheme. The beamwidth of the breadboard system spans a traffic lane width at 45 meters. The paper describes the details of the BAR sensor front-end and preliminary test results sponsored by the National Highway Safety Administration and the Institute for Telecommunication Sciences.