Investigation on the use of time-modulation technique for an ultra-wideband reader

Ultra-wideband Technology is a trusted key for future generation radio frequency identification systems to conquer them as high as the limitations of the ongoing narrow bandwidth radio frequency identification technology like decreasing the space coverage, insufficient ranging resolution for accurate localization, sensitivity to interference, and multiple access capabilities. The idea in practice is to apply the Time Modulation technique which means the presence of switches at the antenna ports, which is a new procedure, but typically adopted for narrowband antennas arrays. So, for the arrays working at a single frequency. Here we are trying to see if it is possible to apply this excitation technique also to ultra-wideband antennas. So, in this case, instead of having two monopoles for instance as well as our application, we have used two Ultra-wideband antennas working in the lower European UWB band [3.1 – 4.8]GHz. For single narrow band antennas, we see what it happens only at single band frequency. In this case, having UWB antennas, we must split our 2GHz band from 3 to 5GHz into windows of 500MHz. This dissertation mainly focuses on the two important characteristics. They are: localization and power transmission both realized by the time modulated antenna array and evaluates their application in the communication system. The first step of experiment localization is carried out on a computer by using the software tool called Computer Simulation Technology (CST) in the range from 3GHz to 5GHz and then merging the results with a MATLAB programming to extract the far-field results and by using Nonlin software which was developed by the researchers of DEI: with this procedure we are able to evaluate the simulation results of far-field by taking into account all the possible phenomena, both linear and non-linear, taking place in the radiating system under test.