Research And Design Of Multi-bands Compact Antennas

With development of mobile communication technology,as the system components of the radiation and receiving of electromagnetic wave,the requirements of the antenna are becoming more and stricter.The modern communication equipment tends to be miniaturized and multi-functional,and presents new challenge to the design of the antenna.Therefore,this article mainly concentrates on the antenna miniaturization and multi-band work.In this thesis,the application background and development status of the antenna have been reviewed,the basic parameters of the antenna,consisting of S parameters,input impedance,bandwidth,efficiency,directional coefficient,polarization and gain have been discussed.The principle and design method of microstip antenna and planar inverted F-type antenna,and other methods of antenna feeding are also studied.Meanwhile,the miniaturization and multi-band technology of antenna are considered.First,a dual-band antenna is designed for aviation and mobile systems.By using groove loading technique and loading short sheeting technique,a L-shaped slot is formed on the radiation patch and a partial radiation patch is removed to change the original current path,realizing dual-frequency work.Then,ultra wideband antenna with notch characteristics for the fifth generation mobile communication system is designed.By slotting at the feeder and radiant patch,a G-shaped slot is formed on the feeder,and a "5" formed by combination of U-shaped and L-shaped slot.Realized a notch characteristic and make the ultra wideband antenna and wireless local area network(5.15-5.825GHz)design without collision frequency.The antenna contains three bands of 3.4-3.6GHz,4.4-4.5GHz,and 4.8-5.0GHz in the fifth generation mobile communication system.Finally,a dual-band implantable antenna is designed for simulating in medical treatment.The antenna realization of miniaturization and multi-frequency by using the materials of Polyimide simulated physical property of implantable material and load shorting pin.The antenna can work in the ISM bands of scientific research(2.42-2.4835GHz)and medical(5.725-5.850GHz).The return loss at the resonant frequency 2.45 GHz and 5.8GHz are both below-20 dB.The antenna can cover the above two ISM bands and miniaturization realized at the same time.