TABLE OF CONTENTS In this chapter some antenna specific aspects are discussed. Chapter 6 dealt in some detail with spatial transforms to reduce the signal vector space in the spatial dimension. Some specific properties of linear arrays were identified. It was shown how to use identical subarrays to reduce the number of antenna channels in order to reduce the number of degrees of freedom of the space-time processor. The concept of overlapping subarrays led directly to the concept of symmetric auxiliary channels (Figure 6.8). Planar array configurations for near-optimum space-time MTI processing were derived (Figure 6.18). In this chapter we try to find out how these or similar techniques can be applied to realistic (also non-linear) antenna arrays.
While in the previous chapters all results were based on linear arrays, in this chapter we consider array configurations which have more aptitude to practical applications. In particular the MTI capability of circular planar arrays as used for example in aircraft nose radar will be analysed. Different subarray configurations will be compared. For instance, random subarrays have been implemented in the ELRA ground-based phased array radar system (SANDER [445]).
Other geometries such as randomly spaced arrays, conformal arrays and planar horizontal array antennas will be discussed as well. Moreover, we will consider antennas with a realistic number of sensors. Most of the results presented in earlier chapters are based on a linear array with 24 elements which is not a realistic number. The antennas used in the following will have 480 or 1204...
