Shaping Flat-Topped Element Patterns in Linear Arrays for Limited-Scan Applications Using Interleaved Directors

This communication presents a limited-scan phased array antenna (PAA) design, incorporating interleaved directors to achieve high gain and suppressed grating lobes for both horizontal polarization (HP) and vertical polarization (VP). The proposed design configures two patch antennas as a subarray driven by a phase-shifted port, thereby expanding the horizontal aperture without increasing the number of phase-shifted ports. Additionally, interleaved directors are integrated onto the array to shape a flat-topped active element pattern (AEP). Moreover, this utilizes vertical space to enhance the active element gain (AEG) without increasing the physical aperture size (footprint). To validate the design, two 10-GHz $1\times 5$ -subarray HP and VP PAAs with $\lambda _{0}$ phase-shifted port spacing are developed. The measured results demonstrate 19.1-/18.5-dBi gains, ±20° scanning ranges, $\le 1.3$ -/0.6-dB scan losses, and $\le -11.1$ -/ −10.5-dB grating lobe levels across 9.7–10.3 GHz.