Design of a Patch Antenna Array for Downlink Rotorcraft System

Rotorcraft are widely used in downlink missions in order to transmit and to capture images for base stations. Traditional dipoles antennas have been used, nevertheless the sitting process faces limitations, due to lack of location. Therefore, this paper presents a microstrip antenna array operating in 5 GHz frequency as an alternative solution to be used in rotorcraft downlink missions. The proposed antenna array, composed by four antennas, was manufactured using low profile printed one and a coaxial feed system. The analysis comprised theoretical calculations, simulations, and a validation through test measurements on a representative vertical tail reduced model, inside a semi anechoic camera. The design results obtained for antenna array constructed on a substrate with relative permittivity $\varepsilon_{r}=2.2$ presented a gain of 7.25 dBi and a better reflection coefficient of -18.5 dB at the design frequency. For a reflection coefficient better than -10 dB a 154.8 MHz bandwidth was obtained.