Research Of Miniature And Multi-band Antenna

With development of mobile communication and integrated circuit technology, the size ofequipment is much smaller than before, and function is more and more. Miniaturization of theseequipments is a new challenge to the researchers and engineers. In order to facilitate the systemintegration and to avoid the mutual interference between the communication equipments,multiband antenna can be useful. Therefore, this article mainly concentrates on the antennaminiaturization and multi-frequency work.Related background and developing situation have been introduced in this thesis. Basictheory of the antenna is being expounded, including the antenna’s main performance index, theprinciple and design method of printed monopole antenna, microstip antenna and planar invertedF-type antenna.First, two tri-band printed antennas are studied. One is composed of a rectangle, a rectanglering and a T-shaped unit. The other adopts nested structure and consists of circular-ring,U-shaped and T-shaped unit. Then, a dual-band planar inverted F-type antenna used in themobile communication system is discussed. This antenna achieved double-frequency by aT-shaped slot in the upper patch, and reduced its size by the folding tail. Finally, adual-frequency microstrip antenna used in BeiDou Navigation Satellite System is studied. Thisantenna adopts double-layered structure. The top layer is circular patch and works in the higherfrequency. The bottom layer is rectangular patch and works in the lower frequency. Slotting andcutting angle technology were respectively used to realize circular polarization, and through thefour slots at the bottom patch to realize miniaturization. Four antennas above have been designedcompletely.