Research On The SISL-based Transition And High-speed Interconnect Technology

In recent years,Substrate Integrated Suspended Line(SISL)has been widely used in various microwave circuits due to its advantages,such as low loss,low cost,and selfencapsulation.To implement the interconnection between SISL and other transmission lines,and to provide a test platform for various SISL circuits,the transition structure design of SISL is very important.With the rapid development of integrated circuit technology to higher speed and larger scale,high-speed interconnect technology between chips and circuits has become a widespread concern.The low-loss and lowdispersion characteristics of SISL makes it easier to be a high-speed interconnect platform with low cost.This paper is based on SISL platform,and the main work carried out is as follows:First,a transition from SISL to suspended coplanar waveguide is designed in this paper.The design is based on standard multi-layer Printed Circuit Board(PCB)process,and the substrates used are all low-cost FR4.Since each part of the circuit is designed in the suspended type,the bandwidth of the transition is greatly improved by three times compared with the state of art.By using SISL with double-metal layer and patterned substrate,the loss of the transition is further reduced.The results show that the proposed back-to-back transition has a return loss of better than 11.4 d B and an insertion loss of less than 2.7 d B from dc to 60 GHz.Second,two surface mount SISL transitions are designed.The signal of SISL is transferred from the middle layer to the top or bottom layer using via hole and half-wall hole coupling,respectively.The test results show that the design can surface mount SISL circuit below 26.5 GHz to the testboards with other types.Last but not least,the high-speed interconnect performance of SISL is studied.The impedance and loss characteristics of SISL are analyzed,and the signal integrity problems of SISL such as attenuation,dispersion,reflection,and ringing are simulated.The simulation result shows that the eye diagram of SISL platform performed well under 200 Gbit/s,illustrate the advantages of using SISL as low-cost high-speed interconnect solution.