Wide-angle Scanning Heterogeneous Element-Based Phased Array Using Novel Scanning Envelope Synthesis Method

Abstract: Two novel methods, including the scanning envelope synthesis (SES) method and the active reflection self-cancellation (ARC) method, are proposed to design wide-angle scanning heterogeneous element phased arrays. Heterogeneous strategy is efficient to extend scanning range but quantitatively characterization of the effect is critically needed to guide design for achieving desired performance. The proposed SES method derives theoretically the relationship between scanning range and the 3dB-beamwidth of the pattern envelope of one phased array, which is linear superposition of active radiation pattern (AEP) magnitude of each element. Therefore, the contribution of each kind of heterogeneity can be quantitatively analyzed for further enhancing the scanning range. As we see, a high active reflection coefficient of the phased array can directly reduce the realized gain. In this way, one ARC method is proposed to reduce the active reflection coefficient by counteracting the reflection component of active reflection coefficient with its transmission component, thereby keeping the realized gain efficiently even when the array scans at large angels. For verification, one 24.5-29.5GHz 4x4 phased array scanning in E-plane is designed and fabricated. Benefiting from the proposed SES method, the scanning range of the prototype is extended up to $\pm74\deg$, around 10{\deg} improvement over one traditional heterogeneous array. Meanwhile, the active reflection coefficient is reduced from -4dB to lower than -7.5dB by applying the ARC method.