| Nowadays, the requirements of miniaturized, broadband and multi-band on antennas used for communication terminals have been proposed, due to the rapid development of mobile and personal communication technologies. Planar inverted-F antenna coming out during these years has been rapidly and widely adopted because it has the outstanding structural properties of small size, light weight, low profile, internally equipped easily fabricated and easily mounted on the carrier. Besides, it can implement the properties of broadband and multi-band.Based on the basic principles of the PIFA antenna, a compact internal wideband PIFA is presented with the help of the commercial electromagnetic simulation software. Good agreement between the measurement and simulation results can be observed, which indicates that the antennas reported in this thesis are practical. Analyse a novel dual-band planar monopole antennas for WLAN terminals .This Antenna with small size, simple Structure light weight and broaden band, are very attractive for nowadays communicationThe main work and creative points of this thesis can be summarized as follows:1 .Make a detailed description on many configurations of different kinds of PIFA antenna based on every part of the PIFA antenna. The principal characteristics and analysis methods are introduced. Meanwhile, the miniaturized, broadband and mufti-band technologies about the micro strip antenna are analyzed and summarized.2. A single-layer single-patch wideband PIFA with a very low profile for mobile terminals is proposed. The relative bandwidth is obviously larger than those of the existing similar structural antennas and reaches 99%. The presented PIFA can cover the frequency bands of WCDMA,CDMA, simultaneously. The return loss, voltage standing wave ratio, radiation patterns, peak gain and current distribution of the presented wideband PIFA are analyzed and discussed. In addition, the antenna is fabricated and tested. The measured results agree well with the simulated results3 .A new kind of planar monopole antennas with slot cut in the radiation patch is put forward. The resonance performance is improved by the slot and frequency band of this planar monopole antenna is wider than that without slot. The effects of slot plate size on the antenna property are studied. The bandwidth of the rectangular planar monopole antennas can be expanded by adjusting the size and location of the slot plate. |
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