An Energy Efficient CMOS THz Inter-chip Interconnect with Spoof Surface Plasmon Polariton (SSPP) Waveguide and SSPP Oscillator

A compact and high-quality-factor slow-wave resonator is reported at the millimeter wave frequency, toward low-channel-crosstalk and low-power on-chip communication. By decorating periodic sub-wavelength stubs onto conventional silicon transmission line structure, surface plasmon polaritons (SPP) can be established for signal propagation with highly localized surface mode. The SPP dispersion relation exhibit a slow-wave behavior which helps to reduce the physical length of transmission lines. Moreover, the metal radiation loss has been found suppressed significantly by introducing the SPP-based metamaterial at the mmW frequency, and the level of rejection of electric dipole is enhanced by stacking more magnetic resonator unit-cell whose replacement is opposite with respect to the existing magnetic SPP-based resonator. An mmW oscillator with a fundamental oscillation frequency of 64GHz is integrated into a phase-locked loop (PLL), generating synchronized surface wave at ~ 100GHz. A silicon interconnect incorporating the above SPP-based oscillator and PLL has been utilized to provide a continuous-wave signal to a silicon I/O interconnect. Simulation results show that the surface-wave oscillator has the ability of strongly confining EM energy with high-Q factor which easily start-up the 140GHz oscillator in low power. Simulated in a standard 40nm CMOS technology, the simulated oscillator phase noise is −116dBc/Hz at 10MHz offset by consuming only 3.5mW power. The I/O interconnect can recover up to 25Gb/s data stream by consuming 41mW power from a 1.1V power supply.