Direction modulation based on planar rectangular non‐linear frequency diverse array

Since its inception, the frequency diverse array (FDA) has attracted extensive attention and research because of its unique properties. However, most of the research primarily focuses on linear geometry FDA, with fewer studies on planar FDA. This letter proposes a design method based on planar rectangular FDA (PRFDA), which adjusts the frequency of each array element nonlinearly so that the beam direction of planar rectangular FDA can change linearly or nonlinearly with time, forming the desired transmit beampattern. Theoretical analysis and simulation results verify the effectiveness of the proposed method. We begin by deriving the precise transmit beampattern for the PRFDA and analyzing the impact of its diverse frequency offset settings on beam direction. Building on this groundwork, we propose a DM method rooted in the PRFDA framework, facilitating linear or nonlinear scanning of its beam across three‐dimensional space.