The throughput performance of intelligently shaped and fixed analog elevation beam patterns in millimeter-wave (mm-wave) base stations with hybrid beamforming (HBF) is assessed for the first time. Distinct spatially heterogeneous user distributions (i.e., uniform, near-site, cell-edge, and weighted uniform and near-site) and propagation environments (i.e., line-of-sight (LoS) with multipath and non-line-of-sight (NLoS) with multipath) are considered. The cosecant-squared and flat-top shaped beam patterns are compared to the benchmark pencil beam pattern with a straightforward electrical downtilt. The LoS simulation results show that in case of unknown weight of user distribution scenarios, the cosecant-squared pattern is the most robust, with a gain of up to 16% in the average system throughput and up to 34% in the 90th percentile user throughout compared to the benchmark. If the near-site case has a greater probability of occurrence than the uniform user distribution (e.g., due to daily events and festivals), the flat-top pattern becomes preferable. In the NLoS scenario, the considered HBF architectures with elevation beam pattern shaping do not bring any performance disadvantages compared to the benchmark HBF.

An antenna array with dual-functionality - electromagnetic radiation and thermal cooling - is proposed. An iterative array design procedure is developed to improve cooling, mutual coupling, side lobe levels, and gain levels in dual-functional antenna arrays with adaptive beam steering. Heatsink-attached patch elements are combined with complementary split ring resonator (CSRR) structures in between the elements, resulting in a novel modular heatsink antenna array. Based on the proposed design, the beam scanning performances of four-element and eight-element linear arrays at 26 GHz are studied. A conventional shorted patch antenna array is used for benchmarking. Through thermal and electromagnetic simulations, it is demonstrated that the proposed antenna array decreases the maximal array temperature by more than 40°C as compared to the benchmark. Moreover, the new design resolves the pattern performance degradation problems in heatsink arrays, while approaching to the electromagnetic performance of the benchmarked array.

This study explores the feasibility of using a hybrid additive manufacturing (AM) to design and produce low-cost, wideband phased array antennas for SatCom applications. We demonstrate the design, fabrication and experimental verificatino of an eight-element linear array comprised of multi-mode dielectric resonator antennas (DRAs) providing full coverage of the K-band SatCom downlink bandwidth (17.7-21.2 GHz). The impact of print settings on material properties is assessed and incorporated into the antenna design process. The manufactured prototype is experimentally verified via impedance and far-field measurements. Furthermore, beam steering capabilities are demonstrated using a commercially available integrated circuit and a simple calibration procedure. The phased array antenna achieves full coverage of the intended band with an input reflectino coefficient below -10 dB. The averaged embedded element pattern demonstrates a realized gain of approximately 3 dB and a half-power beamwidth of 81 degrees. These results highlight the potential of combining hybrid AM and DRA technologies for future mmWave phased array development.

A far-field calibration method based on broadside measurements with a co-polarized and a cross-polarized reference dihedral target is demonstrated for the first time for an asymmetric ±45o linearly polarized 77 GHz frequency modulated continuous wave (FMCW) multiple-input multiple-output (MIMO) automotive radar. A novel extension of the calibration technique for off-broadside targets' phase response is proposed by using an optimized progressive phase compensation. Rotated dihedral and trihedral targets are used for validation. On broadside, the standard deviation of the channels' phase difference is nearly zero degrees for reference targets and under 5o for validation targets. The calibration for off-broadside targets shows that the phase relation in the target's scattering matrix can be retrieved, the accuracy of which is dependent on the target's type and angular position.

A novel ensemble prediction technique is introduced to enhance the accuracy of far-field embedded element pattern (EEP) prediction under mutual coupling (MC) effects, while relaxing the training data size challenge in neural network (NN)-based algorithms. The proposed method integrates a two-stage NN for direct EEP prediction from full-wave simulated pattern data in spherical coordinates with a fully connected NN for the prediction of excitation coefficients of an array of infinitesimal dipoles, approximating the full-wave simulated EEPs via constrained infinitesimal dipole modeling (IDM). Quasi-randomly distributed five-element pin-fed S-band patch antenna arrays are used for demonstration purpose. It is shown that, for a large-sized (3500 topologies) and relatively small-sized (1500 topologies) dataset, incorporating IDM-NN with the benchmarked direct EEP-NN in an ensemble technique increases the pattern prediction accuracy by 11% and 60% on average, respectively.