In this letter, a reconfigurable dual-polarized broadband antenna with beam-steering capabilities using a parasitic layer is proposed for 5G new radio (NR) frequency range 1 (FR-1) applications. The antenna is a dual-port aperture-stacked patch structure with symmetrical orthogonal (horizontal and vertical) currents. The beam-steering is achieved by a pair of reconfigurable cross-shaped parasitic strips, which bestow the antenna three main beam directions θ = { ~ -25 ^° ,0 ^° , ~ 25 ^° }, Ψ = {0 ^° } with pointing and gain ($ 7$ dB) stability across a 30% impedance bandwidth (S ₁₁ , S ₂₂ <; -10 dB) from 3.2 - 4.3 GHz for both ports/polarizations. A prototype of the antenna is manufactured and measured demonstrating results in accordance with simulation expectations.

A low complexity reconfigurable antenna (RA) capable of steering its beam into nine different directions corresponding to $\theta=\{-42^{\circ},0^{\circ},42^{\circ}\}$ in the $\phi=\{25^{\circ},0^{\circ},155^{\circ}\}$ planes, and $\theta=\pm25^{\circ}$ in the $\phi=90^{\circ}$ plane, using a reduced number of switches is presented. The RA operating at $3.4 - 3.8$ GHz consists of a central dipole element excited by a coaxial probe, surrounded by four switchable parasitic dipoles located at different height levels above a ground plane which act as either reflector for the elements located at an upper layer or director for the ones at a lower layer, improving the radiation characteristics of the antenna. Each parasitic dipole is fed with a PIN diode as switch which enables the activation of these elements providing the desired modes of operation. The presented RA was manufactured and measured showing results with a good agreement with the theoretical and numerical simulation.

An ultrawideband rectangular waveguide to microstrip line transition operating at the whole LMDS and Ka band is presented. The transition is based on exciting three overlapped transversal patches that radiate into the narrow wall of the waveguide, making the design feasible to be used in ${\lambda }_g/2$ spaced phased arrays. Both top-side and bottom-side versions were designed and compared to show their differences. They were validated by means of a manufactured back-to-back (B2B) configuration, with a measured fractional bandwidth of 21.2% (top-side) and 23% (bottom-side). The maximum single transition measured insertion losses were 0.67 dB (top-side) and 0.85 dB (bottom-side) in the whole band of operation.

A 3D-printed phased array consisting of four H-Sectorial horn antennas of 200 g weight with an ultra-wideband rectangular-waveguide-to-microstrip-line transition operating over the whole LMDS and K bands (24.25–29.5 GHz) is presented. The transition is based on exciting three overlapped transversal patches that radiate into the waveguide. The transition provides very low insertion losses, ranging from 0.30 dB to 0.67 dB over the whole band of operation (23.5–30.4 GHz). The measured fractional bandwidth of the phased array including the transition was 20.8% (24.75–30.3 GHz). The antenna was measured for six different scanning angles corresponding to six different progressive phases $\alpha$, ranging from 0° to 140° at the central frequency band of operation of 26.5 GHz. The maximum gain was found in the broadside direction $\alpha$ = 0°, with 15.2 dB and efficiency $\eta$ = 78.5%, while the minimum was found for $\alpha$ = 140°, with 13.7 dB and $\eta$ = 91.2%.

A compact triple-layer series fed slot unit array using Groove Gap Waveguide (GGW) technology for 5G millimeter-wave applications is presented in this paper. The design employed a two-step coupling mechanism for the radiating slots. The aperture coupling design when combined with the groove gapWaveguide (GGW) technology allows achieving three different goals: First, a reduction of the array size in the transversal direction, so more unit arrays can be added without grating lobes. Secondly, low insertion losses with high radiation efficiency. And third, a reduction of the manufacturing complexity with good stability against fabrication tolerances of up to 0.1 mm, making the design feasible to be massively deployed. The antenna was fabricated and measured showing good agreement with the numerical simulation results, the antenna provides a peak realized gain of 12.15dB at the central frequency of operation and a fractional bandwidth (FBW) of 9%.