INTRODUCTION

Integrated circuits have been widely used with the rapid development of industrial technology and the continuous increase in people’s demand for electronic products. As a necessary interconnection structure in integrated circuits, the crosstalk has become an important factor restricting the further development of integrated circuits. Therefore, the effect of crosstalk between coupled microstrip lines on integrated circuits must be investigated.
The spacing between the microstrip lines is extremely small due to the high integration requirements of integrated circuits and is easy to cause EM coupling between the microstrip lines, thereby forming crosstalk [1]. To adapt to the development trend of integrated circuits, research scholars at home and abroad have explored methods to reduce crosstalk. They analyze the formation principles and influencing factors of crosstalk between two or more transmission lines [2] and use them as the theoretical basis to develop methods for reducing crosstalk. In accordance with the principle of crosstalk formation, further analysis shows that increasing the transmission line spacing is an effective method to reduce crosstalk [3]. Although this method has better ability to suppress crosstalk, it wastes considerable limited wiring space and does not conform to the development direction of integration. In [4,5,6], the crosstalk is reduced by placing a via-stitch guard or a serpentine guard trace between multiple transmission lines, and the effect of crosstalk suppression is analyzed by EM simulation. Although it has a certain suppression effect on the crosstalk, it affects the wiring method to a certain extent. Resonance problems may also occur. In actual application, the protection line needs to be analyzed and designed separately, which increases the design cost, does not have wide applicability, and is difficult to promote. In [7], the microstrip line structure is covered with a graphene coating, and the crosstalk is reduced by depositing a covering dielectric layer. This method causes the transmission power to be absorbed by the coating to a certain extent, and the use of graphene deposition layers requires higher production costs. In [8,9,10], the method of changing the physical form of the transmission line by inserting rectangular slots for the transmission line or using steeped transmission line is used to reduce the crosstalk. The essence is to reduce the crosstalk by changing the capacitive coupling and inductive coupling ratio. The disadvantage of this method is that the far-end crosstalk reduction effect is not ideal, and the maximum crosstalk suppression effect is only 6 dB for some stepped structures. In [11], a specific DMS is etched on the microstrip line to achieve crosstalk reduction. However, this S-shaped structure design is extremely complicated, the etching is extremely difficult, and the crosstalk suppression effect is limited.
On the basis of the DMS research of [11], this paper designs a TL-shaped DMS, which has a simple structure and is easy to apply in practice. The TL-shaped DMS has a better suppression effect on the far-end crosstalk in the 0–8 GHz frequency band while improving the insertion loss of adjacent microstrip lines, and guaranteeing the signal transmission performance of its own microstrip lines compared with the S-shaped DMS. The proposed method is simulated and verified through theoretical analysis and full-wave EM simulation, using HFSS (a full wave 3-D EM Simulation tool from Ansoft Corporation). Compared with the ordinary coupled microstrip line that does not use this method, the effect of this method on crosstalk suppression is quantified, and its effectiveness is proved. The comparison of measured results of samples and simulation results shows that they are in good agreement, indicating that the proposed method has practical application value and good results.