Crosstalk Suppression Based on Mode Mismatch Between Spoof SPP Transmission Line and Microstrip

We propose an efficient method to suppress the crosstalk based on the mode mismatch between spoof surface plasmon polariton (SPP) transmission line (TL) and microstrip. Since microstrip and spoof SPP TL support quasi-transverse electromagnetic (quasi-TEM) wave and transverse magnetic (TM) wave, respectively, the transmitting electromagnetic (EM) energy can hardly be coupled between these two kinds of TLs, which helps reduce the crosstalk. For the cases of weak and strong coupling, two kinds of structures of spoof SPP TLs are designed. In order to verify the performance of crosstalk suppression, two samples of the coupled TLs are presented and fabricated. Simulated and experimental results show that the crosstalk of both strong and weak coupling is reduced by approximately 35 dB and 30 dB, respectively, by introducing the spoof SPP TL into the microstrip pair. Thus, crosstalk in traditional circuits can be alleviated by the mode mismatch between spoof SPP TLs and microstrips, which is significant for high-speed and high-density integrated systems.