UAVs are extensively utilized across military and civil sectors.
Beyond the flight control system, a stable UAV operation relies heavily on a multi-antenna system for real-time external data exchange. This document presents a customized multi-antenna design for quadcopter UAVs, detailing how 8 antennas operating across 6 frequency bands are integrated within a confined space to support robust system communication.
Design Requirements: The system requires 8 antennas covering 6 frequency bands:
5G Bands: Including
700MHz (UL: 703-743 MHz, DL: 758-798 MHz)
900MHz (UL: 889-915 MHz, DL: 934-960 MHz).
1.4GHz Band: 1412-1497 MHz.
2.4GHz Band: 2412-2472 MHz.
Spatial Constraints: Available space is extremely limited: the rotor housing is a frustum (160mm x 180mm x 40mm) with a 320mm usable circumference. The upper fuselage provides only two 20mm x 44mm areas for antenna placement. The primary challenge lies in fitting all antennas while maintaining high signal integrity.
Key Design Features:
Conformal Rotor Antenna Design: To mitigate signal fluctuations caused by rotor rotation in traditional external antennas, a conformal design is employed. Four 5G antennas and two 1.4G antennas are applied directly to the rotor's frustum surface. With optimized feedline compensation, the 5G antennas cover 690MHz-972MHz, and the 1.4GHz antennas cover 1324MHz-1592MHz.
Simulation model
Antenna picture
Conformal Rotor Antenna Design: To mitigate signal fluctuations caused by rotor rotation in traditional external antennas, a conformal design is employed. Four 5G antennas and two 1.4G antennas are applied directly to the rotor's frustum surface. With optimized feedline compensation, the 5G antennas cover 690MHz-972MHz, and the 1.4GHz antennas cover 1324MHz-1592MHz.
Reflection coefficient of 5G antenna ports
Reflection coefficient of 1.4G antenna ports
Miniaturized Fuselage Antenna Design:
Simulation model
Antenna picture
Two 2.4GHz antennas are placed symmetrically on the fuselage within a 44mm x 20mm footprint. These utilize 3mm FR4 substrates with capacitive compensation and parasitic patches to broaden the bandwidth. The antennas achieve a reflection coefficient (S11) < -10dB within 2.35GHz-2.54GHz and maintain isolation greater than 20dB.
2.4GHz antenna S-parameters
Conclusion: By combining curved conformal designs on rotors with miniaturized fuselage antennas, the connectivity challenges of quadcopter multi-antenna systems are effectively resolved. Field tests demonstrate that the system maintains seamless communication even during high-speed flight or sharp maneuvers.
Shenzhen Keesun Technology Co.,Ltd was founded in Aug of 2012, a high-tech enterprise specializing in various types of antenna and network cable manufacturing.
