Design and optimization of grounded coplanar waveguide and chip cascade structure

Abstract

In order to solve the problem of decreasing transmission efficiency due to impedance abrupt change during the cascade between transmission line and chip, a matching band-line method for X~Ka band was proposed based on the ground coplanar waveguide and chip cascade structure. The input impedance of the chip was extracted by S parameter, and the impedance discontinuities in the RF circuit were analyzed. The impedance matching circuit was designed and the 3D simulation model was established. Through finite element simulation, the influence of matching circuit and bonding lead center distance on RF transmission performance was discussed, and the transmission performance difference of different structures and matching circuits was compared and analyzed. The simulation results show that the matching circuit can make S11<-21 dB and S21>-0.19 dB of the grounded coplanar waveguide and chip cascade structure in the X~Ka band. The optimized grounded coplanar waveguide and chip cascade structure can significantly improve the isolation of RF signal and reduce channel crosstalk while reducing transmission loss, which provides theoretical reference for the design of RF circuits in the centimeter-wave band.

Keywords

• microwave technology; coplanar waveguide; impedance matching; bond-wire; rf performance