CMOS sub-THz on-chip modulator by stacked split ring resonator with high-extinction ratio

A low-loss, high isolation and high extinction-ratio (ER) modulator is proposed in this paper at sub-THz in CMOS. The modulator manifests itself as a modified split ring resonator (SRR) whose magnetic resonance frequency can be modulated by high speed data. Such a magnetic metamaterial achieves a significant reduction of radiation loss with high extinction ratio at sub-THz by stacking two SRR unit-cells with opposite placement. The insertion loss is improved due to a much compact size. Simulation results shows that the proposed modulator can effectively modulate 25Gbps data, achieving 5dB insertion loss at on-state while 28dB isolation at off-state corresponding to 23dB extinction ratio at 140GHz with only an silicon area of 40μm×67μm. The introduced SRR modulator has shown great potential for future on-chip sub-THz communication.