Inverted-F Antenna For Mobile Terminals And Its Minimization

As the development of technology,the size of mobile terminals become smaller and the functions become more powerful than previous generations.Therefore,antennas used in mobile terminals should be developed towards the direction of miniaturization and multi-element.The design of miniaturized antenna and compact multi-antenna system has important theoretical significance and practical value.This thesis studied the miniaturization technique of inverted-F antenna on mobile terminals and it's circular polarized design method.Besides,proposed a multi-antenna system on flat plate with compact structure.The main works are as follows:(1)Combining the technology of miniaturized mobile terminal antenna,a miniaturized planar inverted-F antenna is designed.By utilize the high dielectric constant dielectric-slab,a miniaturized planar inverted-F antenna which working at 1.575GHz is created.In this thesis,a planar inverted-F antenna based on air medium is analyzed.Then,a miniaturized planar inverted-F antenna designed on dielectric-slab with dielectric constant of 10.2 is presented.The radiator size of this antenna is 19.4mm×4.6mm,the thickness of dielectric-slab is 3mm,the working frequency band of |S11|<-10dB is 1.57GHz-1.58GHz and the maximum radiation gain is-1.9dB.In addition,dielectric-slab with dielectric constant of 40 is also used to create miniaturized planar inverted-F antenna.The radiator size of this antenna is 10mm×4.3mm,the thickness of dielectric-slab is 3mm,the working frequency band of |S11|<-10dB is 1.57GHz-1.58GHz and the maximum radiation gain is-2.9dB.The planar inverted-F antenna designed on high dielectric constant dielectric-slab is small in size and easy to integrate.Through the design and analyze above,the dielectric-slab with dielectric constant of 40 is finally chose to design miniaturized planar inverted-F antenna.Then,a four-unit antenna array is designed base on the antenna element proposed above.The distance between each element is 10mm and the axial ratio is lower than 3dB in the working frequency band(1.57GHz-1.58GHz).The gain of circularly polarized multi-antenna system is hig,her than antenna element due to the selection of multi-antenna.The main work is to design a planar inverted-F antenna by using high dielectric constant dielectric-slab.which is small in size and easy to process.(2)According to the technical requirements of 5G mobile communication,a multi-antenna system on flat plate is designed,which has compact structure.The working frequency band of the designed multi-antenna system is 3.3GHz-3.6GHz.The proposed antenna system is consisting of inverted-F antenna and Loop antenna with a neutralization line to decrease the coupling between two central ports.This multi-antenna system has a compact structure,the working frequency band of |S11|<-10dB is 3.3GHz-3.6GHz,the isolation between each port is greater than 17dB and the envelope correlation coefficient(ECC)is lower than 0.1,which can meet the design requirements.The designed multi-antenna system has practical application value and can conform with the metal frame of mobile terminals.