A Low Duty-Cycle Burst-Mode Telemeter Signal Generation Technique for VHF Insect Tracking and Its CMOS Implementation
This brief presents a new circuit design for very highfrequency (VHF) radio telemetry, to miniaturize active RFID tags for tracking small insects and bees. It reports the first CMOS insect tag implementation for generating 150-MHz burst-mode telemeter signals using employing digital approach. This design is vastly different from the present PCB-based analog VHF tag which uses bipolar transistors and large passive components. The new telemeter circuit uses a 150-MHz voltage-controlled ring-oscillator (VCRO) feeding into a cascade of frequency dividers whose outputs are combined (without requiring control logic) to generate extremely low duty-cycle burst-mode transmission signal to save power. In addition, it is the first advancement of the VHF telemeter that incorporates digital code for insect tag identification, compared with the present state-of-the-art analog methods which use small frequency shifts from a reference fo (150 MHz) to fo+f MHz for individual tag identification. In the proposed design, the strength of the modulated carrier signal is used to track the tagged insect location through the triangulation technique. A DRC and pattern-density clean chip-tag was designed for an 8-bit code at a throughput of 576 b/s, on a 28-nm CMOS process. It occupies an active layout area of 1600 μm2 and consumes 8.2 μW.
CMOS circuit design, frequency-shift keying, radio telemetry, very high-frequency (VHF) RFID, voltagecontrolled ring oscillator (VCRO).