Fully integrated wideband phased array with large scan range and 5:1 bandwidth

Abstract

In this work, a fully integrated phased array using multi-layer printed circuit board (PCB) fabrication technologies is presented. This array is directly fed by 50 Ω coaxial cables, without balanced-to-unbalanced transitions. An asymmetric dipole is used to achieve stable input impedance. Furthermore, to broaden the operating bandwidth, a coupling patch is designed beneath the asymmetric dipole , which also eliminates the common-mode resonance and decreases the array profile. In addition, three wide-angle impedance matching (WAIM) layers with different structures are utilised to improve the scan range in all scanning planes. Infinite array simulations indicate that the proposed array can operate over a 5.1:1 bandwidth (2.4 ∼ 12.2 GHz) with an active voltage standing wave ratio below 3 while scanning up to ± 60° in H plane and ±75° in the E plane. Furthermore, the proposed antenna, whose cross-polarization levels remain below −35 and −7.5 dB when scanning up to 75° in the E plane and 60° in the D plane, demonstrates the merits of high polarization purity. Array simulations are verified by the measurements of a 12 × 12 prototype, and good agreement is observed.