A next-generation high-frequency switch made by applying ink-form semiconductor material to a substrate has been developed. By reducing signal loss in the millimeter-wave band without consuming standby power, it is expected to help make 6G and satellite communication equipment smaller and more energy efficient.
Ulsan National Institute of Science and Technology (UNIST) said on the 22nd that a team led by Professor Kim Myoung-su in the Department of Electrical and Electronic Engineering implemented a high-frequency (RF) switch that operates at up to 67 GHz using a molybdenum disulfide thin film made through a solution process.
A high-frequency switch is a semiconductor component that connects or blocks the path through which radio signals travel in smartphones, wireless base stations, satellite communications, and radar. The device made by the team reduced insertion loss during signal transmission at 67 GHz to below 0.1 dB and raised isolation, which represents blocking performance, to at least 35 dB. It delivers about 98% of the input signal while suppressing leakage in the off state to 0.03% or less.
With a structure that places a molybdenum disulfide thin film between metal electrodes, applying a voltage causes copper ions to move and form a current path. Even after power is removed, this path remains, so no additional power is needed to maintain the switch state.
Switching took about 76 nanoseconds, and the energy required to change state once was measured at 1.57 nanojoules. The team also applied the device to a time-delay phase shifter in the 10 GHz range and a 30 GHz phase shifter circuit, confirming its potential use as an actual high-frequency circuit component. The findings were published in the journal Nature Communications.
Manufacturing convenience and durability also improved. Without a transfer process of separately growing a thin film and moving it onto a substrate, it can be applied directly over a large area, and performance was maintained even after 2,000 repeated operations. Compared with existing devices that used mechanically exfoliated thin films and had an operating lifetime of about 100 cycles, stability improved significantly.
Kim said, "The state is maintained even after power is cut, so standby power is not needed," adding, "It could be used to make radio-wave control devices for 6G, satellite communications, and radar smaller and more energy efficient."