Terahertz near-zero reflection modulator based on cascaded electrical length reconfiguration

Return loss is a core indicator of module connectivity performance in integrated communication systems. Reflections from the modulation device can cause power fluctuations, leading to excessive amplitude noise affecting the system's signal-to-noise ratio. To solve the problem of high return loss in existing terahertz amplitude modulation techniques, this paper proposes a near-zero reflection terahertz modulator based on an electrical length reconfiguration cascade. The ON-OFF effect of the modulator is achieved through the cascade's electrical length reconstruction, and the reflections are effectively suppressed from the ON state to the OFF state. Experimental results demonstrate that the proposed modulator achieves a broadband low-reflection effect in the 170–260 GHz band, with a Voltage Standing Wave Ratio (VSWR) of less than 1.5 over a bandwidth of 60 GHz and an optimal VSWR of 1.1. It has the potential to support high-speed response as well as the large-capacity, high-rate data transmission. Accordingly, the proposed modulator offers a promising solution for the design of high-performance terahertz modulators and multi-channel integrated terahertz communication systems.