Research On Miniaturized Planar Inverted F Antenna For Mobile Terminals

With the rapid development of the 3rd generation mobile communication, miniaturization, broadband, and multi-band are demanded for antennas used in wireless communication systems. Planar inverted-F antennas (PIFAs) are widely utilized due to their small size, low profile, and easier to integrate with microwave circuits. Based on the research of miniaturization of PIFAs, a capability improved UWB PIFA is presented in this thesis first. Then, two new kinds of PIFAs, used for WCDMA and TDS-CDMA respectively, are proposed, fabricated and measured. The influences of the main components of mobile terminals on the return loss of the antennas are analyzed by EM simulation software.The main work and creative points of this thesis can be summarized as follows:1. The status of research on PIFA is summarized. The configurations of PIFAs are introduced in detail. Meanwhile, the miniaturization technologies for PIFA are studied and summarized.2. A capability improved miniaturized PIFA for UWB Band is proposed to meet the demands of antennas for mobile communication. The antenna has sizes of 5.5x2.4x4 mm3 and is designed on a substrate withεr=4.4. The performance of the antenna has been improved significantly.3. A five-band PIFA is proposed for WCDMA system. The influences of the main components of mobile terminals, such as the speaker, battery and LED on the main performance of antenna are investigated. The return loss, radiation pattern and current distribution of the antenna are analyzed. The antenna was fabricated and measured, and the measured results are in good agreement with the simulated results.4. A PIFA for TDS-CDMA system is proposed. Slots are cut in both the radiation patch and ground. By folding the radiation patch, the antenna sizes are reduced. Meanwhile, good performances of bandwidth and directivity are achieved. The return loss, radiation pattern and current distribution of the antenna are analyzed. The antenna was fabricated and measured, and the measured results and simulated results are in good agreement.