A Balanced Ternary 3-1 Encoder of Terahertz Metamaterials and Its Sensing Application

A balanced three-value 3-1 encoder for terahertz (THz) metamaterials (MMS) based on graphene plasma-induced transparency (PIT) and phase change material (PCM), for the first time, was proposed. It can achieve 3-1 encoding function in the THz frequency band and belongs to multivalue logic devices. The logic output results can be −1, 0, and 1. The time-domain finite integration (FITD) method was used to simulate and optimize the performance of the encoder. The simulation results show that the device achieves 3-1 encoding function at 2.572 and 4.231 THz (valley of PIT effect), with reflectivity of 93.4% and 93.1%, modulation depth (MD) of 99.9% and 99.8%, extinction ratio (ER) of 12.9 and 9.08 dB, and insertion loss (IL) of 0.02 and 0.15 dB, respectively. When the two encoded outputs of the device are treated as a subset, THz balanced ternary summation operations for pull-up conversion and pull-down conversion can be achieved separately. In addition, the device has excellent sensing performance, with a sensitivity of up to 1.491 THz/RIU in different refractive index environments, and has the characteristic of insensitivity to incident angle, which can be applied in complex encoding and sensing environments. This device can be used in scenarios such as information encryption, data compression, signal anticounterfeiting, and communication protocols. Therefore, this work provides new ideas for the design of THz multivalue logic devices and has certain reference significance in the field of THz communication modulation.