Design Of Miniaturized Antenna For Smart Broadband Terminals

With the developement of communication technology and the smaller volume of smart terminal equipment,the research on miniaturized antennas and broadband antennas becomes a hot spot.In this thesis,on the basis of asymmetric dipole antenna and quasi-selfcomplementary antenna,the miniaturization and broadband design are carried out,and three kinds of miniaturized ultra-wideband antennas are proposed.Firstly,a miniaturized ultra-wideband asymmetric dipole antenna is proposed.The antenna volume is reduced by cutting slots on the upper and lower arms to extend the current path,and the working frequency band is broadended by adding a U-shaped strip near the feeding point and adding a rectangular parasitic patch on the back of the substrate.The overall size of the antenna is 123mm×12mm×1.6mm,simulated and measured results show that the-6d B working bandwidth is 710-940 MHz,1410-1530 MHz and 1640-3800 MHz,and the radiating patterns show omnidirectional characteristics over the whole bandwidth.Secondly,the first miniaturized ultra-wideband quasi-self-complementary antenna loading a branch patch is proposed.The basic structure of the antenna adopts a quasi-selfcomplementary structure shape.By the combination of cutting a U-shaped slot on the right radiating patch and adding a branch patch inside the left counterpart loop-shaped slot patch,the broadband miniaturization design is realized.The overall size of antenna is100mm×30mm×0.8mm,simulated and measured results show that the-6d B working bandwidth is 730-1040 MHz and 1180-1260 MHz in the lower band,and the-10 d B working bandwidth is 1760-4940 MHz in the higher band,with omnidirectional radiating patterns.Finally,on the basis of the first quasi-self-complementary antenna,the second miniaturized ultra-wideband quasi-self-compensating antenna loading a serpentine bending line is proposed.In order to guarantee the coverage of lower band,a loop-shaped slot,a U-shaped slot and a rectangular slot are cut on the right radiating patch.Besides,a serpentine bending line structure is loaded in the left counterpart loop-shaped slot patch to replace the branch patch.The overall size of the antenna is 90mm×30mm×0.8mm.Simulated and measured results show that the-6d B working bandwidth is 700-960 MHz and 1180-1260 MHz in the lower band,and the-10 d B working bandwidth is 1350-4100 MHz in the higher band.Omnidirectional radiation patterns are observed in the ultra-wideband working bandwidth.