New passive metasurface design filters wireless signals without power, offering a breakthrough for Iot and next-gen communication systems.
As wireless communications evolve and devices become smaller, signal interference remains a critical challenge, especially from multipath propagation. Multipath occurs when a signal takes multiple paths to reach a receiver, often arriving at slightly different times and angles. This causes issues like signal fading or ghosting, especially in high-frequency communication.
Traditional solutions have struggled with two major hurdles: all signals, even unwanted ones, share the same frequency, and they arrive at unpredictable angles. These factors limit the effectiveness of conventional, passive signal filters, which can’t adapt in real-time without powered systems.
Now, a research team led by Associate Professor Hiroki Wakatsuchi from the Nagoya Institute of Technology in Japan has unveiled a passive metasurface system that can selectively filter signals—without needing any power or active circuitry. Collaborating with researchers from Osaka and Kyoto universities, the team introduced a design that breaks through long-standing limitations of passive systems.
Their solution involves a time-varying interlocking mechanism embedded in metasurface panels. These panels contain MOSFETS (metal-oxide-semiconductor field-effect transistors), which act as switches that change their state when the first signal arrives. This initial signal passes through, while subsequent, delayed signals are blocked—even if they share the same frequency or come from different directions.
In simulations and real-world tests using a hexagonal prism setup, the system enhanced the desired signal’s strength by 10 dB while suppressing later arrivals. This is the first known passive solution to handle both identical-frequency interference and variable signal angles effectively. The technology could revolutionise how wireless devices handle signal interference, opening doors for next-gen antennas, sensors, and intelligent surfaces that operate efficiently in crowded signal environments.
“Our mechanism doesn’t rely on complex calculations or signal processing,” said Wakatsuchi. “This makes it ideal for low-cost IoT devices that can’t afford high computational demands.”
