A compact dual ring satellite navigation terminal antenna
A compact dual ring dipole antenna for satellite navigation application is proposed.The antenna consists of a dual open-ring dipole,a bottom reflective plane and a side fence.By designing an asymmetric dipole arm,the far-field electric fields generated by currents on the two dipole arms periodically superimpose or cancel each other at different time,resulting in a counterclockwise rotation of the far-field electric field,and ultimately generating the right-handed circular polarization radiation.By loading bent short-circuit fence on the side,the gain pattern and operating bandwidth of the antenna were improved.The overall size of the antenna is 45 mm×45 mm×23 mm,the measured results show that the impedance bandwidth of S11≤-10 dB is from 1.35 to 1.63 GHz,and the axial ratio(RA)bandwidth of less than 3 dB is from 1.41 to 1.69 GHz.The right-handed circular polarization gain at the Beidou B1 frequency point is 4.03 dBi.The proposed antenna has some advantages than traditional circularly polarized antenna,such as a small size,a simple structure,easy to manufacture,and good bandwidth and gain,which is suitable to be used in satellite navigation terminal.