Ultra wideband (UWB) radar for throughwall detection applications

• Main Author: Yeo, Chuan Tian.
• Other Authors: Low Kay Soon
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio
• Online Access: http://hdl.handle.net/10356/15700
• Institution: Nanyang Technological University

With rising demand on breakthrough technologies to replace the existing ones with better performance and quality results, this project investigates the Ultra Wide Band (UWB) technology for through-wall detection of materials to exploit its capabilities to determine the materials’ distance in the wall as well as to differentiate the type of materials. UWB is a radio technology that has a wide bandwidth relative to its centre frequency and has various related applications that ranged from communications system, imaging system, medical measurement system as well as vehicular radar system. It is very widely used in today’s applications because it is not susceptible to any multipath interference and can support high data rate and capacity while using minimal power consumption. Therefore, providing a broad bandwidth and energy saving technology to back up many applications is one of the main strength of UWB and it is proven in military applications before this technology is released to the public. An experimental UWB system has been set up in this project for through-wall applications such as detecting and determining the distance of the materials hidden in the wall by using a simple method of signal wave propagation theory involving the speed of wave travelling in mediums, speed of light and the relative static permittivity as well as differentiating the materials into metals, plastics and cables category by using cross correlation technique. Materials involved include Iron pipe, Copper pipe, PVC pipe, Rigid PVC (uPVC) pipe, LAN cable, Electrical wire and Hollow Concrete Bricks. A comparison table is drawn up to calculate the percentage error between the actual distance and the calculated distance for which the material is hidden in the wall and by varying the parameters like the averaging setting, antenna positions, material positions in the wall as well as the relative static permittivity of the wall, we can select a best experimental setup by choosing the one that can stipulate optimal performance from the system and can yield good results. With regards to the second objective which is to classify the materials into 3 main categories (e.g. metals, plastics and cables), MATLAB code are written for the data to be read in and be processed by utilizing the cross correlation theory to check for similarity of the various signal waveforms detected by the UWB system. Similarly, the experiment parameters such as the averaging value setting in the oscilloscope, the antenna positions as well as the material position in the wall will be changed to investigate and determine which experimental setup specifications can produce the optimal performance and result. After many repeated data collections and detailed analysis of the results, a conclusion was made in finding out the best experimental setup to detect and determine the various materials in the wall for hidden depth and classification. It was found that for the UWB system to perform its best in measuring the depth of the materials hidden in the wall as well as to differentiate the materials apart, an averaging setting of 256 must be set in the Agilent Oscilloscope, Thales Antenna for both the transmitter and receiver must be in the Vertical Centred Position, and last but not least, the material hidden in the wall must be aligned linearly with the positioned antenna in order for the result to be good and accurate. Problems that are encountered during the phase of the research in the period of time are also discussed and suggestions to further improve the system have also been pointed out in assistance to the development of the entire research project.