The Research On Novel Patch Antenna For Dual-Frequency Precise Navigation

With the in-depth transformation and evolution of various generations of wireless communication technologies,coupled with the rapid development of fifth-generation mobile communication technologies(5G),the communications information era has ushered in a new height and challenge.Satellite navigation technology,as the current military and important link in the field of communications,has also begun to gradually spread from early military applications to all aspects of people's lives,especially in recent years,such as navigation maps,food delivery,and early warning of road sections.As a result,"navigation" has become one of the necessary skills for the home to go out.High-precision measurement navigation antenna is a key point of satellite navigation receiver system.The performance of the navigation antenna directly affects the accuracy,range,and aging of the entire navigation system.Therefore,how to design a sophisticated,precise,precise navigation antenna Has always been a topic of common concern in the industry.Currently,the world's more mature navigation systems include GPS,GLONASS,GALILEO,and BeiDou,and each navigation system has L1 and L2 operating frequency bands and there is a certain degree of deviation.Therefore,it is necessary to design a coverage system that covers four major areas.The high-precision antenna of the navigation terminal must have a sufficiently wide radiation bandwidth and a high gain,which is also a problem that is widely concerned and urgently needed to be solved by the industry.Microstrip antennas are widely used in navigation terminals such as GPS and BeiDou due to their small size,easy conformity,low profile,and multipath effects.Two dual-band wideband circularly polarized antennas have been designed.One of them is a dual-broadband circularly polarized antenna composed of single-layer patches for precise satellite navigation is proposed and investigated in this letter.The dual-band design is realized based on the strategy of combining the inner patch in the shape of a cross and the outer annular patch.The two microstrip patches each work as a singlefrequency circular polarization radiator and four metal posts are vertically set under the ends of the cross patch to form four terminal capacitors to lower the resonant frequency of the inner patch,so as to reduce the radiation frequency interval between the inner patch and the outer annular patch to meet the demand of precise satellite navigation.A novel capacitive coupling feed method is used to match the input impedance of the patch antenna,in which the inner and outer patches are simultaneously excited by four metal discs placed under the patches and connected with four feeders through microstrip lines.The four feeders are uniformly distributed on the circumference and attached to the feeding network.The simulation and experimental results show that the proposed antenna can produce dual broadband circularly polarized radiation,and lower backward radiation level can also be observed.The performance indexes in the two bands are L1: 1.145~1.299 GHz,bandwidth 155 MHz,gain 4.0 dB and L2: 1.557-1.654 GHz,bandwidth 97 MHz,gain 3.98 d B.The maximal gains in the two bands are slightly low,but higher gain of the dual-band low-noise amplifier can compensate for lower gain of the passive antenna to make the total gains of the active-antenna to meet the demands of precise navigation terminals.So the proposed single-layer patch antenna will have a good application prospect although its gains in the dual bands are a bit lower.Based on the new feed structure,the other is a dual-band broadband patch antenna covering the world's four major satellite navigation systems is designed.The design of a four-eight feed line,using the eight coaxial feed probes connected two feeding signals,effectively simplifies the complexity of the feeder network.Simultaneously,it ensures that The gain of the antenna radiation,bandwidth and shaft performance.The dual-frequency radiation patch unit adopts the octagonal laminated structure design,and two sets of rectangular tuning unit are placed in each antenna element symmetry.In this way,the antenna radiation beam bandwidth is increased effectively.The design results show that the dual-band antenna unit can guarantee good radiation gain in the frequency range of high frequency 1.482 GHz-1.617 GHz(beam bandwidth 155 MHz)and low frequency 1.191 GHz-1.252 GHz(beam bandwidth 61 MHz).High and low frequency 3 dB axis ratio achieves to-130 ° ~ 130 °,with sensational circular polarization performance.The results are in good agreement with the simulation results.The two antennas designed in this article have achieved breakthroughs in miniaturization.Dual-frequency circularly polarized radiation has been achieved with a single-layer substrate.In-line technology has been used in structures and the coaxial cavity principle using terminal short-circuit has increased coupling.The capacitor implements the down-conversion technique and proposes a new type of capacitive feed to achieve dual-band impedance matching.The other model uses stacked patches and designs a new four-point coupled feed network to meet the requirements of the miniaturized dual-frequency active antenna covering the four navigation systems,providing a priori basis for follow-up research and applying it widely.For navigation systems.