Design of a Chaotic Index Modulation Aided Frequency Diverse Array Scheme for Directional Modulation

Different from traditional phased array (PA), frequency diverse array (FDA) employs an additional frequency offset to its array element so that the transmitted signal is angle-range-dependent. Therefore, FDA can be utilized to realize directional modulation (DM) in both angle and range dimensions. However, traditional DM is mainly realized through optimization methods, which is time-consuming. This article proposes an analytical method to address this problem. For a transmitter with
$M+1$
elements, the proposed approach adopts a chaotic sequence to map out the frequency offsets and the weights of the first
$M$
elements. Then, the weight of the last element can be determined in an analytical way. Numerical simulations are implemented to validate the proposed approach.