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 0.5V. A maximum modulation index of |ΔΓ|²/4 ~ 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.