A super-regenerative radio on plastic based on thin-film transistors and antennas on large flexible sheets for distributed communication links

Abstract

Large-area electronics presents new form factors, enabling ubiquitous systems that are flexible and capable of scaling to very large areas. By processing thin-film transistors (TFTs) at low temperatures on plastic (using organics, amorphous silicon, metal oxides, etc.), blocks such as ADCs, amplifiers, and processors can be realized [1,2]; however, aside from short-range RFID tags [3], wireless links for long-range communication have not been achieved. A key challenge is that wireless systems typically depend on the ability to generate and operate at high frequencies, yet TFTs are limited to very low performance (ft ~1MHz). Specifically, the challenge is low device gm, due to low mobility and limited gate-dielectric scalability, as well as high device capacitance, due to limited feature scalability and large overlaps for alignment margining on flexible substrates. This work presents a super-regenerative (SR) transceiver with integrated antenna on plastic that leverages the attribute of large area to create highquality passives; this enables resonant TFT circuits at high frequencies (near ft) and allows for large antennas, maximizing the communication distance. The resulting carrier frequency is 900kHz, and the range is over 12m (at 2kb/s). As shown in Fig. 25.10.1, this will enable sheets with integrated arrays of radio frontends for distributing a large number of communication links over large areas.