High-Gain Dual-Mode Cylindrical Rectangular Patch Antenna for Airborne Applications

This article presents a conformal antenna system for providing a dual-band high-gain communication link between an unmanned aerial vehicle (UAV) and a ground station where the two bands can be used independently for command-control and data link. A cylindrically conformal rectangular patch antenna operating in the higher order TM21 and TM03 modes is proposed, which produces high gain in both the frequency bands. This is possible by loading the cylindrical-rectangular patch antenna by a centrally located slot, which makes the radiation pattern of the TM21 mode broadside radiating and lowers the sidelobe level of the TM03 mode. Multiport network modeling (MNM) of the structure is done, which leads to the optimum design, and the effect of curvature on antenna performance is also studied. As the antenna has around 60 degrees beamwidth in one of the planes for both the frequency bands, three such antennas are placed on one arm of a quadcopter UAV so that 180 degrees coverage can be obtained by switching the antennas. The antenna system has a simulated gain of 7.94 and 10.21 dBi at 10.288 and 12.412 GHz, respectively. A single slot-loaded cylindrical-rectangular patch antenna is fabricated and the measured results are compared with those obtained by MNM and simulation. The antenna gives a gain of 7.46 and 9.83 dBi at the frequencies of 10.323 and 12.46 GHz, respectively.