Research On Miniaturized Helical Antenna For Global Navigation Satellite System Terminal

helical antenna is widely used in the field of satellite navigation because of its good circular polarization performance,uniform heart-shaped radiation pattern and high low elevation gain.With the development of miniaturization of satellite navigation terminal equipment,the requirements of antenna size in practical engineering applications are increasingly stringent.Therefore,miniaturization while ensuring the radiation performance of antenna has become a research hotspot.This paper studies the miniaturized helical antenna for global navigation satellite system terminal.1.A miniaturized PIFA four arm helical antenna is proposed.The four helical arms adopt the PIFA structure,the terminal is folded down to reduce the axial height of the antenna,and the impedance matching is realized by using the short-circuit branch on the left side of the input;the bottom area is reduced by half by the double-layer feeding network,and the phase delay is generated through the coaxial inner and outer core and the annular microstrip line,so as to realize the circular polarization radiation of the antenna.The antenna works in GPS L1 band,and its overall size is0.10λ₀×0.10λ₀×0.11λ₀（λ₀ is the free space wavelength corresponding to the low frequency center of the antenna）.The test results show that the impedance bandwidth ofis 45MHz（1.555-1.660GHz）,the 3d B axial ratio bandwidth is451MHz（1.435-1.886GHz）,and the peak gain in the working frequency band is4.36d Bi.2.A miniaturized self phase shifting helical antenna is proposed.Based on the research of the previous chapter,the microstrip line of the feed network is transformed into a part of the radiator to realize miniaturization,and the input impedance and phase delay required by the self phase shift are provided by the bottom ring structure.The antenna can cover GPS L1,BDS B1 and GLONASS L1 bands,and its overall size is0.18λ₀×0.18λ₀×0.19λ₀.The test results show that the impedance bandwidth of is 210MHz（1.468-1.678GHz）,the 3d B axial ratio bandwidth is 544MHz（1.264-1.808GHz）,and the peak gain in the working frequency band is5.01d Bi.3.A miniaturized coupled dual frequency helical antenna is proposed.The inner and outer helical arms of the dielectric plate are coupled to produce dual frequency resonance,the inner and outer helixes adopt the short-circuit structure with orthogonal terminals;the outer helix adopts the self phase shifting feeding structure proposed in the previous chapter to realize circular polarization radiation;the short-circuit structure of the inner coupled helix is deformed into an orthogonal angstrom axe shape to realize miniaturization.The antenna can cover BDS B1 and S bands,and its overall size is0.15λ₀×0.15λ₀×0.19λ₀.The test results show that the impedance bandwidth of is 112MHz（1.464-1.576GHz）and 377MHz（2.352-2.729GHz）;the 3d Baxial ratio bandwidth is 314MHz（1.334-1.648GHz）and 696MHz（2.264-2.960GHz）;the peak gain in the working frequency band is 4.55d Bi and 3.42d Bi.