A Modified Bow-tie Antenna for Wi-Fi and WiMAX Applications

Résumé du livre

A bow-tie antenna is made from a bi-triangular sheet of metal with the feed at i ts vertex. It is used extensively in many applications such as ground penetratin g radar and mobile station. Bow-tie antennas have many advantages such as low pr ofile, high radiation efficiency, ease of manufacturing, and low fabrication cos t. Moreover, a bow-tie antenna can be printed on a substrate where each arm is p laced on the upper or lower surface of the substrate. The feeding of such struct ure is done by designing appropriate striplines that are connected to a coaxial feed which is placed on one of the edges of the substrate. This thesis introduces new techniques that can be used to increase the resonanc e of an antenna and to obtain a multi function antenna that can be used for seve ral communication applications. The basic idea consists of taking different slot s configurations on each arm of the bow-tie. This idea was implemented on both b ow-tie and printed bow-tie antennas on a FR4-epoxy substrate. From all the simulations that were conducted on bow-tie antenna, it was conclud ed that that it's impossible to obtain a dual resonance at 2.4 GHz and 3.4 GHz w ith the use of circular slots. However, the introduction of triangular slots sho wed that a dual resonance at 2.4 GHz and 3.4 GHz can be achieved. Also, the intr oduction of circular slots produced a dual resonance at 2.4 GHz and 5 GHz. There fore, the final design consists of incorporating both triangular and circular sl ots where all the bands for Wi-Fi and WiMAX are covered. The fabrication of such design was not done due to many problems. Hence, a newer design was simulated s o that it can be fabricated by the available facilities. The new idea consists of printing the bow-tie arms on a substrate. In fact, the same procedures done on bow-tie antenna were done on printed bow-tie antenna, wh ere different slots configurations were taken. The difference between the final design of a printed bow-tie and the design of a normal bow-tie is that the incor poration of circular slots of different dimensions produces resonance on the thr ee bands for Wi-Fi and WiMAX. A prototype of this design was fabricated and test ed, where a complete analogy was found between tested and simulated data.