A Study Of Dual Band Slot Loop Antenna

In recent years, the ultra-wide band antenna or multi-band antenna has found extensively studied and applied because of the use in a large number of wireless communication techonology. For Wi-Fi applications, one antenna with features of matching and relatively consistent beamwidth in dual band is desired. The antenna coverd both 2.4GHz and 5GHz could be deployed in any region directly. At the same time, relatively consistent beamwidth in the all operating bands is desired to maintain the same signal coverage. At present, most dual band matching antennas are designed with two antennas in parallel, which is hardly to achieve good cross polarization and radiation pattern performance, those designs are not widely used in engineering.In this paper, a dual band slot loop antenna for Wi-Fi application is proposed which is achieved with relatively consistent beamwidth in dual band, and the paper focuses on the following work.(1)Study the slot antenna, an ultra wide band slot loop antenna is presented. With the doubled aperture in higer band, the proposed antenna generates splitting beams.(2)For Wi-Fi environment, an ultra wide band balun and stepped reflector are designed for the slot loop antenna.(3)After analyzing aperture, a noval slot loop antenena with arch structure is proposed in this paper. An equivalent array model for analyzing beamwidth and an expression calculating the null point of pattern is derived as a function of the source spacing are introduced in this paper. The noval slot loop antenna achieves relatively consistent beamwidth and good cross polarization performance.Finally, the porposed slot antenna with arch sturcture is validated by the measurements of a prototype, results shows the antenna is with VSWR less than 1.5 in dual band, good vertical polarization, as well as high gain and front to back ratio, which can meet the performance requirements for Wi-Fi applications.