Microwave to Millimeter-Wave (mmWave) Tightly Coupled Dipole Array (TCDA) With 20:1 Bandwidth Using a Hybrid PCB-3D Printing Fabrication Approach

The vast majority of mmWave arrays utilize planar topologies due to fabrication and assembly constraints. However, planar architectures bring the antenna element too close to the ground plane, limiting the achievable bandwidth (BW). In this paper, we introduce a vertically integrated UWB array that operates from microwave to mmWave frequencies. The novel antenna array operates from 2 to 40 GHz, i.e., 20:1 bandwidth. The enabling novelty is the combination of PCB fabrication technologies with 3D-printing technology. Specifically, unlike previous designs, all components of the array are printed on the same plane and the vertical dipole boards are assembled using a 3D-printed structure. The array employs the concept of tightly coupled dipoles to achieve Ultra-Wideband (UWB) operation. Infinite array simulations showed a VSWR < 2.8 at broadside and scanning capabilities down to $45^{o}$ in all planes. These simulations were validated through fabrication and measurements of a 21 × 15 prototype in conjunction with finite array simulations.