Application And Analysis Of Dispersion Characteristic Of ACPW

Coplanar waveguide (CPW) is important planar transmission line in microwave and millimeter-wave integrated circuits (MMIC). It is known that CPW is symmetrical in theory, but it is asymmetrical in practice. And asymmetrical coplanar waveguide (ACPW) is very useful in some particular applications. Finite-Difference Time-Domain (FDTD) is first proposed to analyze dispersion characteristic of ACPW and ACPW with conductor backing, and the measurements are presented firstly in this paper.In all numerical arithmetics, FDTD is a very efficient method. It is proposed firstly in this paper that the full space calculation model and mixed absorbing boundary conditions (ABCs) based on MUR-PML. The full space calculation model, which suits for the asymmetric structure sometimes even including air below the surface of medium, can enable simulative result to approach real one. The FDTD algorithm based on the mixed ABCs is proper to calculate the transmission line where the electromagnetic wave is transmitted in order to send electromagnetic energy along central conductor. The calculation efficiency will be raised if the PML absorbing boundary condition is set on both planes of transmitting direction and so is the MUR two-order absorbing boundary condition in the other planes. The numerical result is almost consistent with the one in XFDTD software.CPW is extensively applied not only to transmit signal but also to manufacture a large number kinds of apparatus in MMIC, but it is prevented from connection to slotline due to its symmetric structure. Comparing with the CPW, ACPW is more common and flexible. So the ACPW-Slotline Transition is advanced firstly, and its S parameter is proposed in this paper.