Study On The Navigation Receiving And Anti-jamming Antennas For BDS And GPS Applications

The navigation receiving and anti-jamming antennas for BeiDou Navigation Satellite System?BDS?and Global Positioning System?GPS?applications are studied in this dissertation with the researched projects.The research work can be divided into two parts.The first part is the research on the passive and active receiving antennas for BDS and GPS applications.The passive receiving antennas include a dual-band circularly polarized?CP?antenna with broad beamwidth,a wideband CP antenna with broad beamwidth,a compact CP antenna and a compact dual-band CP antenna.The active receiving antenna is an integrated antenna which combines an active circuit with a passive antenna.The second part is the research on the anti-jamming antenna array for BDS and GPS applications.The contexts of the research are as follows:Part 1:Research on the navigation receiving antennas for BDS and GPS applications1.Research on a dual-band CP antenna with broad beamwidthIn order to solve the problem of low number of satellites in orbit for BDS applications,the design requirements of dual-band and broad beamwidth for receiving antenna performance are put forward by the ground receiving application system.The research to solve the problems are carried out in this dissertation.At first,the technical scheme of realizing dual-band CP antenna with broad beamwidth is studied.A new resonant frequency is generated at the low frequency end by using the coupling between the U shape patch and the arc shape patch and the dual-band operation is realized.By combining the?shape pattern generated by the metal shorted posts with the O shape pattern generated by the horizontal metal patch,the gain in the low elevation angle is enhanced and the beamwidth of the antenna is broadened at the same time.Based on the simulation,a prototype of the proposed antenna is fabricated and measured.Experimental results show that the proposed antenna has the properties of dual-band circular polarization,broad beamwidth and high gain in low elevation angles.The research results have been applied in a certain type of terminal receiving system at present.2.Design of a wideband CP antenna with broad beamwidth According to the application requirements of dual mode operation for the BDS and GPS ground terminal receiving system,the design scheme of wideband CP antenna with broad beamwidth is studied in this dissertation.By filling a thick substrate layer on the back of the crossed printed dipoles,the beamwidth of the antenna is broadened by using the refraction of the filling substrate layer to the backward reflected wave.By loading a notched-corner metal cavity around the crossed dipoles and using the coupling between them,a new resonant frequency point is generated at the low frequency end and the characteristics of wide bandwidth is realized.Meanwhile,due to the vertical distributed current generated on the metal cavity,the gain in the low elevation angle is enhanced and the beamwidth of the antenna is further broadened.Based on the simulation,a prototype of the proposed antenna is fabricated and measured.Due to the properties of wide bandwidth,wide beamwidth,circular polarization and high gain in low elevation angles,the antenna has been applied in a certain type of BDS and GPS terminal receiving system at present.3.Research on a compact CP antennaIn view of the development trend of BDS user terminal receiver becoming portable and compact,the design scheme of compact CP antenna is studied in this dissertation.In this study,by loading the printed inductors and the metal shorted posts,the inductive loads are introduced in the inverted-L antenna and the resonant frequency is decreased so that the miniaturization of the antenna is realized.The overall dimension of the antenna is only0.17?₀?0.17?₀?0.10?₀,where?₀ is the corresponding free-space wavelength at 1.268GHz.Based on the simulation,a prototype of the proposed antenna is fabricated and measured.Experimental results show that the proposed antenna has the properties of miniaturization and circular polarization.At present,the proposed antenna has been applied in a certain type of BDS portable terminal receiving system.4.Design of a compact dual-band CP antennaIn order to meet the application requirements of dual-frequency positioning in BDS portable terminal receiving system,a compact dual-band CP antenna working in BDS-B3and BDS-B1 frequency bands is designed in this dissertation.The dual-band operation is realized by changing the shape of the arm to a U shape for the inverted-F antenna.By loading the chip inductors in the arms of the antenna,the inductive loads are introduced in the antenna and the resonant frequency is decreased so that the compactness is realized.The overall dimension of the proposed antenna is only 0.21?₀?0.21?₀?0.06?₀,where?₀ is the corresponding free-space wavelength at 1.268GHz.Based on the simulation,a prototype of the proposed antenna is fabricated and measured.Experimental results show that the proposed antenna has the properties of miniaturization and dual-band circular polarization.At present,the proposed antenna has been applied in a certain type of BDS portable terminal receiving system at present.5.Design of an active receiving antenna for BDS and GPSAccording to the application requirements of BDS and GPS systems in high precision measurement field,the design requirements of multi-band circular polarization,low noise figure and high out-of-band inhibition of the receiving RF?Radio Frequency?circuits are proposed for the receiving antenna.In order to meet the design requirements,a design scheme of an active receiving antenna is proposed in this dissertation.In this study,the laminated microstrip patch antenna is used as the design form of the passive antenna covering the corresponding working frequency bands of BDS and GPS.The received signal of the passive antenna is divided into two paths.The functions of signal amplification and out-of-band inhibition are realized by cascading three-stage low noise amplifiers,two-stage filters and a first-stage attenuator.The passive antenna and the receiving RF circuit are integrated by tile interconnection.Based on the simulated results,an active receiving antenna prototype is fabricated and tested.Experimental results show that the proposed antenna meet the above design requirements.At present,the proposed antenna has been applied to a certain receiving system in high precision measurement field.Part 2:Research on the anti-jamming antenna array for BDS and GPSIn order to meet the application requirements of beam forming for the anti-jamming antenna system,the design requirements of multiple array elements,wide band circular polarization,high gain in low elevation angles and low mutual coupling between array elements are put forward for the electrical performance of the anti-jamming antenna array.In this study,the design scheme of an anti-jamming antenna array is studied at first.With a given carrier platform,7 antenna elements are arranged in the form of a uniform planar circular ring array.By adding substrate layer and notched-corner metal cavity,the antenna array element can meet the requirements of wideband,circular polarization and compactness.By adjusting the included angle between the surrounding elements and reference element,the mutual coupling between the array elements is reduced and the gain of the antenna array elements in the low elevation direction is increased.The anti-interference performance of the antenna array is verified by the joint simulation method of MATLAB and ANSYS HFSS.The proposed antenna array has a good anti-interference performance.Based on the simulation,a prototype of the anti-jamming antenna array is fabricated and measured.Experimental results show that the proposed antenna meet the above design requirements.At present,the proposed antenna has been used in the anti-jamming system of a certain type of receiver and the actual application effect is good.