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A planar dielectric lens has been designed for low‐cost multi‐beam antennas in the 26‐GHz band of 5G communications. The lens feeder is a stacked‐patch microstrip antenna with four input ports, thus permitting four independent high‐directivity radiation beams. Maximum steering of 25° can be attained, which a simulated gain over 18 dB for all scanning angles. The antenna has been implemented with low‐cost manufacturing techniques. The feeder is fabricated as a printed circuit board, while the lens is realized as a perforated 3D‐printed dielectric piece. Experimental results confirm the multi‐beam capability of the lens system, suggesting that the spillover efficiency can be improved in further works.

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This work presents the design and prototyping of a reconfigurable phased array in Ku band (16 to 18 GHz) implemented in waveguide technology. The design is based on the use of a novel seamless waveguide module integrating four reconfigurable phase shifters to adjust the relative phase shift between the unitary elements of a linear array, which are illuminated uniformly by a corporate waveguide feeding network. The phase shifters are implemented by a 90 ○ hybrid coupler in waveguide technology where two of its ports are loaded with a tunable reactive load, implemented in this proof of concept with a tuning screw. The four phase shifters have been manufactured in a single part using direct metal laser sintering, avoiding the losses related to bad electric contacts and misalignments associated to multipart devices. This also simplifies the assembly of the full phased array, leading to a modular approach with three parts whose design can be addressed separately. The experimental results for the complete array antenna show great performance and demonstrate that the main-lobe of the radiation pattern can be effectively scanned continuously between the angles −25 ○ and 25 ○ , with a high efficiency in the whole design band thanks to the proposed waveguide implementation.

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Two designs of conical-beam array antennas are presented for different fifth-generation applications. They are based on slotted cylindrical waveguides and a travelling-wave topology, where the waveguide is used to progressively excite a cross-slot array. A total of 384 cross-slots, formed by transversal and longitudinal slots, are grouped in rings of eight equally-spaced cross-slots. The propagation of TM01 and TE01 modes in the cylindrical waveguide can provide dual polarization by the independent excitation of transversal and longitudinal slots, respectively. Firstly, a dual linearly-polarized antenna design in the 37-40 GHz band is presented, conforming a high-gain conical-beam pattern. Secondly, a similar antenna design working in the 5G dual-band of 26-30 GHz and 37-40 GHz is also presented. In this last case, transversal and longitudinal slots are designed to radiate at the two different frequency bands of 26-30 GHz (vertical polarization) and 37-40 GHz (horizontal polarization), recently assigned for very high-speed 5G applications. In order to experimentally validate the proposed topologies, the dual-band design has been prototyped by combining 3D-printing and CNC milling techniques, providing high experimental performance. Directive tilted omnidirectional coverages with peak realized gains around 14 dBi have been obtained, as well as a total efficiency between 83% and 90% for both frequency bands.