Phase-Shifter-Free Reconfigurable Array Architecture Using Pattern Rotation - Part I: Theory and Validation

A unified reconfigurable array architecture is proposed, supporting two-phase modulation mechanisms: element rotation and initial phase modulation. Both approaches enable subarray-level beam steering without needing phase shifters or complex feeding networks, facilitating large-scale array beam scanning with fewer radio frequency channels. An innovative beamforming method is introduced in Part I, leveraging element rotation within an Ns-element (6-element) linear subarray. Vertical partition scanning within ±θmax (±10°) is achieved by presetting the tilt angles of the elements in the Ns-element subarray (6-element). A longer linear array of Ny-elements formed by Ms-subarrays is formed (Ny=Ms×Ns). A high-profile Nx×Ny array (8×24) of Yagi elements achieves two-dimensional beam scanning at 4.5 GHz with a grating lobe suppression algorithm. To generalize this approach, a theoretical framework is established that incorporates concepts such as phase smoothing region, deflection phase, intrinsic phase, and initial phase modulation, ultimately extending the rotation-based method into a universal initial phase control scheme. Simulation and measurement results confirm that replacing conventional small-ratio power dividers with 1-to-Ns equal-dividers preserves low sidelobe levels in vertical scanning, maintains original horizontal scanning performance, and achieves channel capacity parity with full-channel systems. Part II will further validate the approach by designing and implementing a dual-polarized base station antenna element with electronically tunable initial phase control.