Design of an optimized linear sparse antenna array for a 24 GHz radar tachymeter

This paper presents the design of a linear antenna array for use in a 24 GHz radar tachymeter. The task of the proposed radar tachymeter is the precise measurement of the distance and angle to a cooperative transponder. To obtain the desired high accuracy, we designed an optimized sparse antenna array. The antenna pattern was selected using a brute-force optimization method. A fixed number of array elements was placed on a limited number of allowed grid positions and the array pattern with the best figure of merit for the given radar tachymeter application was selected. This approach can be successfully employed for sparse antenna array designs where multiple constraints such as aperture size limitations or number and spacing of antenna array elements are given. Distance and angle measurements taken with the implemented optimized array show excellent results. The standard deviations in range and azimuth were 8.6 mm and 0.1°, respectively for a range of several hundred meters.