Design and Performance Analysis of UWB MIMO Antenna with Diversity Techniques

Abstract

In the recent time, small hand held wireless devices are offering high speed multimedia data services. Thanks for Ultra-wide-band technology which has wide spectrum and provide such high speed wireless services. However, UWB technology is suffered with two major drawbacks; it provides short range communication and poor link reliability due to multipath fading. Combine a Multiple-Input Multiple-Output (MIMO) system with UWB (i.e. UWB-MIMO system) is an innovative solution to overcome form above said drawbacks. In the MIMO antenna systems designing several antennas are placed at the transmitter and/or the receiver side. The MIMO antenna can increase; the system throughput, link reliability in the multipath fading environment, range of the communication systems without required of additional transmitting power and radio spectrum. The compact size UWB-MIMO antenna is to be required for space limited hand held mobile devices. The antenna size optimization is a challenging issue for both academia and industry. On the size reduction of the antenna; distance between the radiating elements is decreased, mutual coupling is increased or isolation is decreased. Therefore, closely placed radiating elements of the MIMO antenna is highly correlated to each other and resulting for antenna performance degrade. The aims of the thesis are to investigate novel methods of MIMO antenna size optimization and enhance the MIMO/ diversity performance of the MIMO antenna system. newlineThe background and theory of the UWB and MIMO system is discussed briefly first. Several merits of the multiple antenna systems are discussed and analyzed. The various decoupling methods are investigated of the MIMO antenna design with improved isolation for UWB applications. The size optimization of the UWB-MIMO antenna using surrogate assisted optimization model is carried out and improved isolation is accomplished by inverted prism ground stubs. newline