Correlation suppression performance for coherent signals in RD-SSP-MUSIC with a seven-element ESPAR antenna

This paper clarifies correlation suppression performance of RD (ReactanceDomain)-SSP (Spatial smoothing Preprocessing) -MUSIC in a radio environment where two coherent signals with perfect correlation impinge on a seven-element circular ESPAR (Electronically Steerable Parasitic Array Radiator) antenna from various sets of DOAs (Directions-Of-Arrival). The RD-SSP-MUSIC scheme has been proposed for the ESPAR antenna to estimate the DOAs of coherent signals by F/B (Forward-Backward) SSP utilizing three pairs of diamond-shaped snharrays. Simulation results show that the SSPOOO, which is one of the F/B SSP of the ESPAR antenna, can obtain a lower correlation toward two signals from 100 degrees and 120 degrees, compared with the signals from 160 degrees and 180 degrees. On the other hand, the signals with DOAs of 160 degrees and 180 degrees are distinguished by the SSPO60. That is, the variance of an angular resolution on two coherent signals from close DOAs to a parallel sliding direction is compensated by another type of snbarray. Moreover, we have found that the smallest angular distance distinguishable by the SSPOOO is 18.0 degrees given by a set of8l.O degrees and 99.0 degrees.