Design Of Dual-band Wide Beam Active Receiver Antenna For GPS

Satellite navigation system provides a lot of convenience for people's life,at present,the largest and most widely used satellite navigation system is the global positioning system in the United States.Antenna plays an important role in positioning and communication systems,its performance determines the pros and cons of the system.There are many kinds of antennas,quadrifilar helix antenna has good circular polarization performance,and the radiation pattern can cover the upper half of the space,which conforms to the requirements of the global positioning system.In this paper,relevant research and design of dual-band quadrifilar helix antenna are carried out,and the main work completed is as follows:(1)A new quadrifilar helix antenna structure is designed.Using 3D printing technology and dielectric loading method,the size of the antenna is effectively reduced and the axial ratio beam width is expanded.After simulation and optimization,the antenna structure is a geometry composed of a hollow cylinder and a hollow spherical ring,the hollow cylinder has a radius of 10mm and a height of 22mm,the inner diameter of the hollo'w spherical ring is 10mm,its outer surface is a part of the sphere with a radius of 5.5mm,the height of spherical ring is 10.55mm.the size of antenna is smaller than most four-arm spiral antennas on the market.Measured results show that,the beam width is greater than 120°,the axial ratio beam width is greater than 130°,which is better than miniaturized quadrifilar helix antenna appeared in recent years.(2)A compact feed network is designed.In order to reduce the circuit size,a power divider chip(BP2G1+)is used in the design to realize power distribution In addition,the feed network adopts a novel cross type phase shifter,which has the characteristics of small size,simple structure and easy processing compared with the traditional schiffman phase shifter,and can provide 90° and 180° phase shift in the frequency band of 1.2GHz?1.6GHz.By combining the antenna with the network,the measured results shows that the performance of the antenna meets the design requirements and the network can provide a good feed for the antenna.(3)A low noise amplifier which can be used with the designed antenna is designed.The low noise amplifier adopts the form of cascade,and the input and output matching of amplifying circuit adopts the coupling line matching circuit.Simulation and physical test show that the designed low noise amplifier is well matched in the operating band of 1.2GHz?1.6GHz,with the gain greater than 25dB and the noise coefficient less than 1.5db,which indicate that the low noise amplifier e ffectively improves the performance of the active receiving antenna.