Compact E-Band Waveguide Phased-Array Antenna Using 3D-Printed Stainless-Steel Technology

This paper presents a low-profile dual-polarized waveguide phased-array antenna operating in the E-band, enabled by additive manufacturing using micro laser sintering (MLS) of stainless steel. The proposed array employs continuous transverse stub (CTS) radiating elements to achieve wide impedance bandwidth, high aperture efficiency, and stable wideangle beam scanning, while maintaining a compact profile suitable for millimeter-wave systems. A dual-polarized unit cell with an element spacing of approximately half a wavelength at the highest operating frequency is developed to support beam scanning beyond ±60°. A 3×3-elements array is fabricated and measured to characterize the active impedance behavior, polarization isolation, and scanning performance using the active element pattern (AEP) method. To further demonstrate scalability, an 8 × 8 series-fed array is implemented based on the same radiating element. Measured results show good agreement with simulations, with active reflection coefficients below −10 dB over the 65-80 GHz band, gain variation within 5.2 dB over a ±60° scan range, and aperture efficiency exceeding 82%, despite the use of stainless steel. The results validate the proposed antenna architecture and demonstrate the feasibility of MLSbased metal additive manufacturing for high-performance Eband phased-array antennas.