Multi- Gigabit Patch Antenna Wireless Links: An Experimental Investigation.

With the adoption of IEEE. 802 .11 / 16 wireless networks are fast becoming a preferred solution to the Access “Last Mile” problem. The ease of installation and minimum disruption to infrastructure makes wireless systems an attractive and economical alternative to conventional “hard connected” layouts. With connecting optical systems commonly operating at 10 Gb/s and the latest generation VDSL modems requiring 10 MHz of bandwidth, conventional wireless systems are challenged. The aim of this project is to demonstrate a wireless system that could operate at data rates commensurate to that of these “wired “ and optical systems. To accomplish this, a wide bandwidth suspended patch antenna was developed and modelled using Agilent ADS software. Difficulties with the antenna feed were overcome using an integrated stub tuning method. Three antennas were designed to operate at centre frequencies of 2.4 GHz, 4 GHz, and 6 GHz, these being combined into an array. Performance of the individual elements was analysed both experimentally and with the use of modelling, both sets of results were then compared and used to optimise the final design. A standard 4 QAM technique was employed to double the system throughput. A phase locked loop based carrier and clock recovery circuit was implemented to enable autonomous demodulation and data analysis over the target distance of 60 metres. The complete system was then evaluated in terms of data throughput. By combining the bandwidth capability of each antenna, and utilising the linear polarisation properties of the patches, three channels were created on each of two polarisation planes. In this way a total throughput of 10.4 Gbs of PRBS data was transmitted.