Research On Multi-Frequency And Broadband Miniature Planar Antenna

Antennas are the necessary components in modern wireless systems. With the development of miniaturization of electronic communications systems, properties of miniaturization, multi-frequency and broadband for these systems are demand. The miniature planar antenna has the feature of compact size, low profile, easy to fabricate, and easy to integrate with microwave circuit, these properties meet the demands of the above system, so the miniature planar antenna has been found widely applications.Based on previous studies of small plane antennas, this thesis has proposed some kinds of multi-frequency and ultra-wideband (UWB) miniature planar antennas fed by near couples microstrip in the help of HFSS. The multi-frequency antennas have been fabricated and tested. The experiment results are consistent with the simulation results. This proves the efficiency of the design. The main works and creative parts of this thesis are summarized as follows:1. The basic configuration and principles of miniature plane antenna, mainly microstrip antenna and planar monopole antenna are studied. The miniaturization, broadband, multi-frequency technologies and feed mode of miniature plane antenna are introduced.2. The radiation principle of square ring antenna is studied in this thesis. The influences of antenna configuration parameters on antenna performance are analyzed. A kind of multi-frequency antenna using coplanar rings are proposed and designed. Each resonant frequency of the antennas can be adjusted independently. The variations of the return loss, the current distribution and the radiation patterns of double rings and triple ring antennas are analyzed. The antennas are then fabricated and tested. The experimental results are consistent with the simulation results. The results show that the proposed antennas have good performance on frequency choose and meet the demand very well.3. A kind of UWB annual ring patch antenna and a kind of UWB annual ring slot antenna are proposed and designed. The influences of different inner and outer radius and the size of ground plate on antenna bandwidth are analyzed. The simulation study results show that the proposed antennas have good performances and can be use in UWB communication systems.