Ultrawideband Phased Antenna Arrays Based on Tightly Coupled Open Folded Dipoles

Dielectric superstrates have been commonly utilized in tightly coupled dipole arrays (TCDAs) to help achieve better impedance matching over wide bandwidth and large scan volume. However, the dielectric slabs inevitably increase the total weight and fabrication complexity for TCDAs. Thus, an investigation of a new TCDA element excluding additional dielectric superstrates is proposed in this letter. Specifically, the tightly coupled elements in the proposed array are open folded dipoles, in which the gaps provide additional capacitance as compared to normal dipoles, thus resulting in better impedance matching. The proposed antenna array achieves 7.33:1 bandwidth (0.3-2.2 GHz) while scanning up to ±70° in the E-/D-plane and ±50° in the H-plane, subject to VSWR <; 3.0. A prototype for an 8 × 8 array was fabricated and measured. Good agreement is achieved between measured and simulation results, thus validating the good performance of the proposed array.