Design Of Compact Circularly Polarized Conformal Antenna Array

With the development of information technology,research in the field of radar antennas has developed rapidly.The conformal antenna has its own unique advantages,such as:tightly combined with the shape of the carrier structure,reducing the influence of the antenna on the carrier structure;does not change the aerodynamic performance of the carrier;provides wide angle coverage,and improves the scanning range of the phased array radar.Conformal antennas can be widely used in satellites,airplanes,missiles,ships,and buildings.When they are conformal to missiles,they can improve navigation and communication without changing their structure.The diversification of the application of the missile-shaped conformal antenna has become a research hotspot in the field of antennas.For the missile-borne navigation conformal antenna,problems such as single operating frequency,poor circular polarization performance,and large structural size are prominent.Based on the missile-borne navigation conformal antenna,this paper studies the circular and cylindrical carrier conformal antenna arrays,compact and dual-frequency conformal arrays.The main work contents are as follows:First,the design of the Global Positioning System(GPS)conformal antenna for the round table carrier.Based on the requirements of engineering projects,we designed a microstrip patch conformal antenna array that improves impedance matching through the branch matching segment and uses the chamfered form to excite circular polarization.Unfolding the table carrier conformal array is equivalent to sector plane array.In the design,sector structure layout antenna unit,and then use two-stage one-two-two T-type power division network to form an antenna array.The antenna is processed and tested,and the test results meet the design specifications.Second,the design of the BeiDou Navigation Satellite System(BDS)compact conformal antenna array for cylindrical carriers.Based on the first part,the axial height of the carrier platform is reduced,and the space size is insufficient.It is proposed to etch a rectangular groove at the edge of the microstrip patch antenna to achieve miniaturization.A two-division T-type power division network is used to form an equal-spoke,phase-shifted 90° excitation on the two input ends of the antenna unit,thereby implementing a doubly-fed circularly polarized antenna.Then use the power distribution network to form an antenna array,then simulate,process and test it.Finally,the measured results meet the design specifications.Third,the design of the BDS and GPS compact dual-frequency conformal antenna array of the round table carrier.The axial height of the carrier platform is smaller,and the miniaturization of the microstrip patch is not satisfactory.If we choose a square ring microstrip patch structure and the microstrip line coupling feed mode can meet the requirements of small size structure.The antenna unit is fed by a Wilkinson type power dividing network with two output ports with a phase difference of 90°,implementing broadband circular polarization.The antenna array is composed of a T-type power dividing network.The antenna array processing test of the design shows that the design indicators are basically satisfied.