Backscatter systems, devices, and techniques utilizing CSS modulation and/or higher order harmonic cancellation

A backscatter device comprising:

• an antenna configured to backscatter a carrier signal having a first frequency;
• baseband circuitry configured to provide data for transmission;
• a modulator coupled to the baseband circuitry and configured to provide an output signal in accordance with the data;
• and
• a switch coupled to the antenna, the switch configured to control an impedance of the backscatter device to backscatter the carrier signal in accordance with the output signal such that the first frequency is mixed with the output signal to transmit a backscattered signal, wherein the backscattered signal has suppressed third and fifth harmonic components.

A system comprising:

• a carrier signal generator configured to provide a carrier signal having a first frequency;
• a backscatter device positioned to backscatter the carrier signal to provide a backscattered signal comprising a chirp spread spectrum signal, wherein the backscatter device comprises a switch coupled to an antenna, the switch configured to control an impedance of the backscatter device to backscatter the carrier signal in accordance with an output signal from a frequency synthesizer, such that the first frequency is mixed with the output signal to provide the chirp spread spectrum signal;
• and
• a receiver configured to receive the chirp spread spectrum signal.