Mixed-Modes-Enabled Element-Level Beamforming Antenna With Enhanced Isolation for Phased Array Applications

We introduce an element-level beamforming (ELB) antenna under mixed modes for large-element spacing array applications. Mixed modes and high co-polarized port isolation are obtained simultaneously by aligning the operation bands of odd and even modes. The proposed antenna can synchronously control the main beam steering and radiation null by finely adjusting the amplitude and phase of the signals at each element. At the array level, individual units can produce desired beam patterns in specified directions, allowing for the expansion of scanning ranges, grating lobe suppression, and generation of multiple simultaneous beams. The scanning characteristics of an ELB-based antenna array under 1-
$\lambda $
element spacing have been studied, where 2.6-dB gain fluctuation at
$\theta $
= ±60° with a peak range up to
$\theta $
= ±75°, and more than 16-dB full-angle grating-lobe suppressions are achieved. The ELB-based antenna is promising for phased antenna arrays with enhanced radiation properties and flexible element spacings.