With the introduction of 5G communication systems operating in the mm-wave frequency range, new opportunities in terms of multimedia services and applications will become available. For this to happen, several technical challenges from an antenna standpoint need to be addressed. The achievements of high-gain characteristics and agile beamforming with wide-scan capabilities are the main targets of the ongoing research on mm-wave antenna arrays. In this paper, an up-to-date overview of antenna array technology for wireless communications at mm-wave frequencies is given. Particular focus is put on the review of the state-of-the art and most advanced antenna array concepts for point-to-point and point-to-multipoint radio links at said frequencies. Various figures of merit are assessed for a comprehensive analysis and bench marking of the technical solutions investigated in the presented survey.

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A Review of Antenna Array Technologies for Point-to-Point and Point-to-Multipoint Wireless Communications at Millimeter-Wave Frequencies

In this paper three types of contactless vertical transitions from microstrip to double ridge waveguide are presented. The designs are compact in size and robust, with improved isolation by employing a pin structure, making them ideal for 5G mmWave phased arrays. All transitions cover the 26.5 – 29.5 GHz band, their dimensions are less than half a wavelength in pitch and have insertion losses less than 0.6 dB. The three designs apply different matching strategies and offer a trade-off between bandwidth and PCB areas. Finally, the behavior within an array configuration is analyzed.

Microstrip to Ridge Gap Waveguide Transition for 28 GHz Steerable Slot Array Antennas

This paper addresses millimeter-wave propagation estimation for urban macro-cellular and urban micro-cellular scenarios at 28 GHz, 38 GHz, 58 GHz, and 73 GHz, and observes the corresponding propagation characteristics indicating the path loss for UMa and UMi scenarios using 3GPP proposed path loss models, in both line-of-sight and non-line-of-sight environments, for the efficient deployment of 5G cellular communication networks. The purpose of this work is to characterize the mmWave spectrum depending on the distance for the urban environment to determine the optimal mmWave frequency band according to the transmitter-receiver separation distance to ensure the necessary connectivity and data rate.

MmWave Propagation Characteristics Analysis for UMa and UMi Wireless Communications

mmWave frequencies offer unprecedented capacity but also new technical challenges. Current solutions typically adopt integrated PCB antennas, however they still face issues when it comes to coverage, power consumption and cost. Instead, we present a 5G mmWave antenna platform demonstrating a different approach based on Gapwaves technology. The proposed design is an integrated all-metal multi-layer assembly, offering low-loss feeding, high-gain subarray, high-Q filters and exceptional thermal handling. To support these claims, active measurement of beam steering, EIRP and temperature are presented. Results from this small demonstration unit are very encouraging and show performance challenging that of much larger systems.

Magnus Gustafsson

Papers

5G mmWave Beam Steering Antenna Development and Testing