Design Of Antenna For Multi-rotor Drone Measurement System

In recent years,faced with the difficulty of measuring large outdoor antennas,a multi-rotor drone measurement system has been derived to measure the electrical performance of large outdoor antennas in outside.The system is easily affected by factors such as signal mutual interference,drone’s flight attitude,outdoor complex electromagnetic environment,etc,which lead to the decline of the measurement accuracy of the system,and even the drone’s flight safety will be threatened.In order to improve the measurement accuracy of the system and ensure the safe flight of the multi-rotor drone,this thesis starts with the measurement antennas and communication antenna applied to the multi-rotor drone measurement system.The research in this thesis studies the following questions:the signal mutual interference between the antenna signal and the multi-rotor drone signal,the reduction of the gain of the measuring antenna in the elevation direction when the antenna to be tested has an elevation angle,and the directional interference caused by the outdoor complex electromagnetic environment.Two measurement antennas and one communication antenna of the multi-rotor drone measurement system.The main research contents of this thesis are as follows:1.In order to solve the problem of discontinuous signal reception caused by the continuous change of the flying attitude of the multi-rotor drone when it performs the measurement task,it is necessary to select an omnidirectional antenna as the measurement antenna.In order to avoid the problem of signal mutual interference,it is necessary to introduce bang-notch technology.Aiming at these two requirements,this thesis designs a broadband omnidirectional dielectric resonator antenna with double-notch characteristics.Firstly,the microstrip feed is designed to excite two dielectric resonators to produce omnidirectional radiation,which overcomes the influence caused by the change of flight attitude.Then,a Cshaped resonant structure is introduced on both sides of the feed and a Y-shaped gap is etched on the ground,so that the antenna generates band-notched in the multi-rotor drone communication bands 1.430 GHz-1.444 GHz and 2.408 GHz-2.440 GHz.Simulation results show:the impedance bandwidth is of 100.7%(1.07 GHz-3.24 GHz),the gain variation in the band is between 1.4 dBi and 3.4 dBi,the gain variation in the vertical plane is less than 3 dB.2.In order to solve the problem that the gain of omnidirectional measurement antenna decreases in the inclination direction,resulting in the low received signal strength of the antenna,when the multi-rotor drone is measuring some antennas with a certain elevation angle relative to the ground.A conical beam omnidirectional antenna loaded with artificial magnetic conductor is designed in this thesis.Firstly,a ring antenna with good omnidirectional radiation characteristics is designed,and then an artificial magnetic conductor surface is designed.Through the AMC surface,the omnidirectional radiation characteristics of the ring antenna are transformed into the omnidirectional radiation characteristics of conical beam.Simulation results show:the impedance bandwidth is of 26%(1.84 GHz～2.39 GHz).the gain variation at θ=30° in the band is between 3.7 dBi and 5 dBi,the gain change on a cross section of θ=30° is less than 3 dB.3.In order to solve the problem of flight insecurity caused by directional interference of multi-rotor drone flying in outside,a pattern reconfigurable antenna based on microstrip quasi Yagi structure is designed in this thesis.Firstly,six microstrip quasi Yagi elements arranged along the circumference are designed as the radiation structure.Then a feeding network is designed to excite the radiating element of the antenna.Six PIN tubes are loaded in the feeding network and the on-off of the PIN tubes is controlled to realize the free switching of six different pattern modes,so that the antenna has the Pattern reconfigurable feature.Simulation results show the impedance bandwidth of the antenna under the six modes can cover from 2.408 GHz to 2.440 GHz,and the radiation pattern of the antenna under the six modes can cover φ=0° to φ=360° for the the entire xoy plane,the gain in the maximum radiation direction is maintained at about 6.2 dBi.