Bendable Wideband 4 × 4 Dipole Array at X-Band With Adaptive Beamformer for Wide Angle Wireless Sensing

A low-cost, modular, bendable dipole antenna array with wide bandwidth is presented for X-band sensing applications. The antenna elements, realized as printed dipoles on a substrate mounted on a ground plane, use a printed balun to enable broadband, balanced excitation. A parasitic dipole is included to increase the bandwidth of the printed dipole. Four arrays of four elements each are printed on Rogers RO4350B-based strips to realize the 4×4 array. The ground plane is fabricated using thin flexible copper-clad FR-4 substrate, enabling one-dimensional flexibility. As an example, the array is conformed to a cylinder with a diameter of 12 cm for beamforming. Minimum variance distortionless response (MVDR) beamforming is used and adapted to the wideband conformal array. Experimental results show that the range of beam steering angles can be significantly extended with the proposed design, while keeping sidelobe levels low.