Research On Power Divider Based On Left-handed Materials

Power divider as a passive microwave device is widely used in wireless communication field, but with user’s higher and higher requirement of its performance and compact structure. The conventional power divider can’t meet their requirements. Left-handed materials(LHMs) is widely used in microwave devices and have good performance, because of it has unique properties.The composite right/left-handed transmission line(CRLH TL) consisting of left-handed materials and ordinary transmission lines. The paper utlizes the nonlinear phase characteristics of CRLH TL and high impedance characteristics of defected ground structure(DGS) to design several of different power dividers. By means of theoretical analysis, calculation, simulation and experimental verification, the main works are as follow:(1) The basic theory and unique properties of the LHMs can be described. The paper especially focus on the theory of CRLH TL. A novel 4-way broadband Wilkinson phase shift power divider based on the nonlinear characteristics of CRLH TL is presented. The experimental results show that the phase shifter is operating in a wide bandwidth about 600MHz to realize 180°phase shift. This circuit has been successfully applied in the phased-array antenna.(2) The conventional 3-way power divider can be changed by transform Y-shaped network into△-shaped network. The transmission line of 2πelectrical length can be substituted by CRLH TL to realize 0°phase shift. The size of the power divider can be reduced. In order to reduce the losses and increase the Q, the paper select stripline structure to design power divider. The experimental results show that the power divider can be used in maritime satellite communication system. According to the high impedance of T-shaped DGS, which is introduced and applied to design a 1:4 unequal Wilkinson power divider. The power divider can be realized in the laboratory. The experimental results show that the power dividing ration is exactly 1:4 and the circuit will be smaller by employing delay the group velocity of DGS.(3) Gysel power divider is widely used in high-power system. It meets the basic theory of the power divider. The design use phase advance feature of CRLH TL can reduce the size of the power divider. The results of the power divider can get from experimental. Bagley Polygon power divider not only avoid the isolation resistors but also conveniently realize odd-way outputs. In this work a dual compact three way Bagley Polygon power divider is implemented using CRLH TL for the GSM frequencies of 900MHz and 1800MHz. The experimental results demonstrate that the physical dimensions of the power divider have been significantly reduced by CRLH TL.