Research On MIMO Channel Model And UWB Filter

With the continuous development of the wireless communication techniques and wireless multimedia services, it is desired that the next wireless communication systems will support higher data rate transmission and better quality of service for subscribers. The Multiple-Input Multiple-Output(MIMO) technique as one of the most promising breakthrough to modem communication technology, is becoming the hot topic in3G mobile communications and broadband wireless access systems. The performance of MIMO communication depends largely on the characteristics of the radio channels. Hence, researches on the modeling of MIMO channel are needed in order to facilitate the development of MIMO techniques.On the other hand, Ultra-wideband (UWB) wireless communication system has attracted a wide attention in the world since its advantages of high-speed data rate, low power consumption, great multi-path interference rejection capability. As the key component of UWB system, UWB filter will affect the performance of the UWB system deeply, and the research and the design of the UWB bandpass filter are becoming an important work.This thesis focuses on the modeling of the MIMO channels and the design of UWB bandpass filter. The main contents of this thesis are expressed as follows:In terms of MIMO channels modeling, a new approach of the deterministic MIMO channel models is proposed. The theoretical framework of the modeling is based on magnetic field integral equation (MFIF) and perturbation method which adapt to the arbitrary multiple antenna MIMO system in free space and the scattering environment. Multiple antenna MIMO system in free space and scattering environment are simulated in the thesis. And the modeling calculated result and CST simulation result of the S parameters for MIMO system are given and discussed, which show good agreement with each other.A new method to determine the permittivity of dielectric is presented in this thesis, which is based on the modeling theory of the MIMO channel in scattering environment. This method is suitable for measuring the dielectric of arbitrary shape and the experimental results of samples of different shapes are presents.In terms of UWB filter designing, this thesis presents a new structure of ultra-wideband (UWB) bandpass filter. The passband of the designed filter is2.8GHz-11.8GHz with a relative bandwidth of123%. Pairs of defected ground structures (DGS) are designed to suppress the spurious passband, and obtain a wide stopband bandwidth with15dB attenuation up-to30GHz. The notched bands created by folded coupling arm or embedded open-circuited stub are also studied and analyzed.