A Novel Dual Function Receiver–Backscatterer at mm-Wave Using an ADC Front End

This work presents a concept for a mm-wave backscatterer based on a single III-V diode detector, whose load impedance is actively controlled using the internal states of a commercially available ADC. By periodically switching the buffer and PGA (Programmable Gain Amplifier) configurations, the ADC presents two distinct input impedances to the diode, enabling reflection-based modulation without any external RF switches or active high-frequency circuitry. Extensive measurements from 1 to 40\,GHz demonstrate consistent two-state separation, with the strongest modulation occurring at a bias of 0.5\,V. A maximum modulation depth of $|\Delta\Gamma|^2/4 \approx 0.40$ is achieved at 35\,GHz, confirming the feasibility of diode–ADC co-design for mm-wave backscatter. The proposed architecture significantly simplifies backscatter transmitter design and establishes a promising pathway toward highly integrated, low-power, multi-functional RF sensing and communication nodes.