| Four novel dual-band microstrip antennas for Wireless local area network (WLAN) application have been proposed in this thesis. These antennas satisfy the requirements of the three frequency bands which WLAN standard used. These antennas have been fabricated and measured. The experiment results are agreed with those of the simulation, so that the results verify the rationality feasibility of the antenna design. This thesis is summarized as follows:1,Improve the traditional coaxial feed rectangular microstrip patch antenna by means of one patch multi-mode. In order to get dual-band operating characteristics and enhance the operation bandwidth of the antenna, we slot in the patch and multilayer dielectric plate with air layer was used. The antenna can cover the three bands which WLAN required successfully. The proposed antenna has good radiation characteristics and high gain.2,A dual-band printed monopole microstrip antenna is proposed. In order to make the antenna got dual-band operating characteristics we add parasitic element on the radiation patch. The parasitic elements and the finite ground plane can broaden the bandwidth of the antenna. The antenna has a wide operation frequency band which can cover the three WLAN bands completely, and the radiation characteristics and gain of the antenna is good.3,A slot antenna fed by microstrip line with inset U-strip and E-strip for dual frequency operates in WLAN applications is proposed. Finally the antenna has enough bandwidth to cover the WLAN band. The gain of the antenna is stable and has good radiation characteristics.4,Because the portable devices on wireless communications require small size antennas, a dual-band planar inverted-F antenna (PIFA) has been designed. This antenna has a simple structure and a small size and its bandwidth can cover the WLAN bands completely. The antenna's gain and radiation characteristics satisfy the requirements of the WLAN communication systems completely.Multi-frequency, broadband and miniaturization technology in antenna design theory are all used in the four proposed antennas, these antennas not only verify the correctness of the theory, but also are a practice of the theory. Measured results of actual antenna are agreed well with the simulated results which proved that the antenna can satisfy the requirements of the WLAN communication systems, and can be used in the WLAN communication systems. |
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