Reconfigurable Antenna for UAV-Assisted Wide Coverage Air-to-Ground Communications

Abstract

A wide-coverage unmanned aerial vehicle (UAV) antenna system for air-to-ground communications is proposed in this paper. The proposed antenna system has reconfigurable beam patterns based on five sets of dual-polarization and high gain antennas. Each antenna set is configured by a dualpolarization crossed inverted-V radiator and switched feed network to drive switched beamforming operations. Depending on the switch modes of the proposed antenna, main beam direction and circular polarization types can be independently selected. Further, each antenna set is faced toward the ground level at different angles from the center of UAV to provide wide beam coverage. To verify the antenna performance, each antenna set is designed at the center frequency of 5.7 GHz and total five sets are integrated with a switched feed network and a microcontroller. To implement the wide angle switched beamforming with 2-D angle-shifted main beams, a 3-D printed conformal fixture is used to connect both the antenna module and a drone body. The maximum measured bandwidth was more than 22% and the measured peak gain with the de-embedded switch feed network loss was about 10.2 dBic.

Smart Selective Antennas System (SSAS): Improving 4G LTE Connectivity for UAVs Using Directive Selective Antennas

“…In [19], a review of patch antennas used for UAV-borne systems, where the need of 360 • beam coverage at relatively high gain is addressed, is presented, then identifying multiple switched patch antennas and phased array patch antennas as valuable solution for this problem. In [20], a system composed by five dual-port dual-polarization crossed inverted-V antennas optimized for UAV Air-to-Ground communication is proposed, where the feed network is based on a Single-Pole-Five-Throw (SP5T) switch (antenna selection) and five Single-Pole-Double-Throw (SP2T) switches (polarization selection). The system is designed to operate in the frequency band from 5.5 GHz to 5.9 GHz, and has been tested in the field with Continuous Wave (CW) signals, using a portable spectrum analyzer as ground base receiver.…”

“…Then, a cellular modem has been used to connect to a real LTE cellular network. Moreover, the experimental evaluation in [20] has been conducted with the UAV at fixed height and position, while the ground base receiver is placed in different positions.Similarly, the antenna system in [21] has been tested with CW transmitted signal only in laboratory conditions, at a distance between transmitter and receiver equal to 25 cm.…”

“…A major drawback of the antenna developed in this work is the limitation of the linear polarization. Further developments of the system will focus on developing an antenna with similar bandwidth, gain and weight, but able to operate in dualpolarization, as described in [20] and [21].…”

Software-Defined UAV Networks for 6G Systems: Requirements, Opportunities, Emerging Techniques, Challenges, and Research Directions

“…Antenna beamforming: Antenna beamforming is an approach for directing signals in specific directions while minimizing interference as well as improving signal strength [119]. Moreover, antenna beamforming is also capable of enhancing communication between UAVs and the GCSs in SDUAV networking, leading to higher data rates, a greater communication range, and a more dependable connection for 6G networks [120]. To improve communication between various UAVs, antenna beamforming can be utilized to steer signals around the shortcomings of conventional omnidirectional antennas used in UAVs.…”