Advances in Wideband Phased Antenna Array Design and Manufacturing at Millimeter Waves

Fifth-generation (5G) telecommunication networks have shifted to millimeter-waves (mm-waves) to provide a broader spectrum of available frequency for the increasing number of wireless devices and to meet the demand for higher data rates. Antenna arrays are key components of these new radio-frequency (RF) systems. The antennas become physically smaller, and electrically larger arrays become feasible with an entire array fitting into the same volume as a single dual-polarized sub-6 GHz antenna element, the type previously used. Larger antenna arrays enable massive multiple-input and multiple-output (MIMO) and beam steering, increasing the potential available data rates even further. Furthermore, the technology in beam-steerable antenna arrays in telecommunication applications converges with the hardware used previously only in sensors, such as radars. In future, sensing could become an integrated part of multipurpose antenna arrays and used together with telecommunication applications, to increase the safety of autonomous vehicles, for example. This thesis presents antenna arrays for mm-wave handset and base station applications at Ka- and E-bands, which are portions of the radio spectrum in the microwave range of frequencies at 26–40 GHz and 60–90 GHz, respectively. Three different antenna array designs are discussed: a dual-polarized Vivaldi antenna array for Ka-band; a co-designed Vivaldi antenna array for handsets; and a dielectric-filled waveguide antenna array. The dual-polarized Ka-band Vivaldi antenna is an element design that can be made from a single metal piece or by using additive manufacturing processes. The antenna is surface-mounted on a printed circuit board (PCB) and does not require separate RF connectors, enabling more cost-efficient devices. The antenna is characterized by a beam-steerable, 8×8 element configuration. Additionally, a modular design with 4×4 elements and beamforming integrated circuits (ICs) with the same footprint has been developed. The antenna array design is demonstrated using both conventional machining and additive manufacturing processes. The mm-wave Vivaldi antenna array for metal-rim handsets is co-designed with the 4G Long Term Evolution (LTE) antenna. The antenna array is implemented within the same volume as the LTE antenna without affecting the performance of either antenna. The mm-wave antenna radiates through an aperture in the metal rim of the handset and is suitable for 25–30 GHz frequencies with good electrical performance.The dielectric-filled waveguide antenna is designed for E-band. The developed antenna uses dielectric-filled waveguides to decrease the waveguide dimensions and to enable an element spacing of λ/2. The proposed design is a four-element array that is fed from a single WR-12 waveguide port. It uses a 1-to-4 waveguide power division network.