Low-power, nonvolatile RF switch promises energy-efficient 6G and autonomous vehicle communications

A research team affiliated with UNIST has unveiled a new semiconductor device optimized for the next-generation 6G era and autonomous driving, offering low power consumption and nonvolatile operation. This innovative device can also be integrated into variable filter circuits capable of tuning the central frequency band, paving the way for more compact and energy-efficient communication equipment.

Jointly led by Professor Myungsoo Kim of the Department of Electrical Engineering and Professor Tae-Sik Yoon of the Graduate School of Semiconductor Materials and Devices Engineering at UNIST, the team announced the development of nonvolatile radio-frequency (RF) switches based on vanadium oxide (VO_x) for next-generation wireless communication systems. The paper is published in Advanced Science.

RF switches are essential semiconductor components in modern wireless communication systems, such as autonomous systems, smartphones, VR, and AR. They control the flow of high-frequency signals within circuits by connecting or disconnecting specific pathways, enabling reliable signal routing.

The newly developed RF switch operates without standby power, functioning effectively in high-frequency bands suitable for high-speed, high-capacity communications. This is made possible by its memristor structure—a device that can retain its resistance state even when powered off, owing to its nonvolatile properties.

This characteristic allows the switch to maintain its set state without consuming standby power, significantly reducing energy consumption. Additionally, the memristor’s resistance switching speed is on the order of a few nanoseconds, enabling rapid on/off switching and minimizing signal processing delays.

Experimental tests demonstrated that the device can handle high-frequency signals up to 67 GHz, maintaining low insertion loss (below 0.46 dB) in the ON state and high isolation (above 20 dB) in the OFF state. Lower insertion loss and higher isolation directly correspond to improved communication quality.

Simulations further indicated that the device could operate at frequencies up to 4.5 THz, representing the highest cutoff frequency reported among oxide-based RF switches to date.

The research team also developed a tunable bandpass filter utilizing this RF switch. This electronic circuit allows the center frequency to be adjusted within a range of approximately 600 MHz. Such a multiband filter simplifies circuit design and reduces size, making it highly suitable for high-integration wireless communication devices.

Professor Kim Myungsoo stated, “The memristor-based RF switch demonstrates the potential to realize compact RF front-ends that combine frequency selectivity with energy efficiency. This development could serve as a foundational component for next-generation wireless communication systems.”