Design Of Helicopter Airborne Antenna For Satellite Communication

At present, the helicopter becomes more and more popular in civil activities. Satellite communication has become one of the important ways of communication. It need that the antennas receive and transmit signals between the helicopter and the satellite. The posture of helicopter during the flying is flexible, and the helicopter can not be fixed in one direction to communicate with the satellite. The circular polarization antenna is design in this thesis.Based on the radiation theory of the dipole antenna and the generation mechanism of circular polarization antenna, a crossing printed dipole antenna is designed in this thesis. The antenna achieves the stable gain and radiation pattern within operating frequency band. In the design, a circular parasitic is used to expand the antenna impedance bandwidth. A pair of dipole antenna is cross placed. The 90° bridge generates two signals which are equal in amplitude and 90° phase difference to feed the two dipole antennas.The parameters of antenna are analyzed and optimized via commercial electromagnetic simulation software. The antenna is fabricated and measured. The measurement results show that the bandwidth of S-parameter below-10 d B and the axial ratio below 3dB are both within 1GHz to 2GHz. In the L band, the gain of the antenna is above 4dB.