Signal Modulation and Mixing by a Single Flexible Double-Gate InGaZnO TFT

Organic and inorganic thin-film electronics on flexible substrates offer a platform to develop lightweight wearable devices and circuits capable of conforming to unconventional surfaces. However, their performance, such as their frequency response and limited circuit complexity, still limits their applications. In this context, flexible InGaZnO-based thin-film transistors (TFTs) have been widely explored as they combine mechanical flexibility with comparably good electrical performance. This work presents the use of a single InGaZnO double gate TFT able to modulate the amplitude and mix the frequencies of AC signals with frequencies up to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\approx 10\text{kHz}$</tex>. When used as a modulator, the design with two independent asymmetric gates allows the simultaneous application of a high-frequency carrier and a low-frequency modulation signal. Operated at a supply voltage of 5 V, the device shows a modulation index up to 75%, which varies <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&lt; 15\%$</tex> when the TFT is bent to a radius of 5 mm. This suggests the possibility of such configurations being used as simple low-frequency transmitters.