High-Resolution Direction Finding Exploiting the Additional Spatial Phase Shift Generated in Switched Parasitic Antenna Arrays.

Abstract

The benefit of producing an additional spatial phase shift to signals received by a switched active switched parasitic antenna array (SASPA) will be examined in this work. The added spatial phase shift, in addition to the spatial phase shifts a received signal experiences when moving across an antenna array, greatly enhances the resolution of direction of arrival (DOA) estimation. It inherently occurs when each antenna in an SASPA array is switched from parasitic to active state while leaving the others as parasites at one time. The improvement is due to scaling up the steering matrix of the measurements of a receiving SASPA array by a unitary matrix. The effect of this matrix is as if the signals are received with higher signal to noise ratio (SNR). Several simulations in this work depict that SASPA arrays can estimate the DOAs with a resolution much higher than all-active antenna arrays even when the array size is limited and the signals are received from critical directions and spatially very close to each other. The root mean square error (RMSE) criterion is examined as well, revealing that the estimated DOA using SASPA arrays very closely matches the true value over a wide range of SNR.