RF reflectometry and charge sensing
A resonant circuit senses tiny changes in device impedance.
$$\Gamma=\frac{Z_{\rm in}-Z_0}{Z_{\rm in}+Z_0}$$
Physical intuition
A resonant circuit senses tiny changes in device impedance.
Deep dive: physical mechanism
A sensor dot or gate capacitance shifts the reflection coefficient of a radio-frequency resonator.
What is measured experimentally?
I/Q demodulation yields a state-dependent signal.
Assumptions, noise and limitations
Impedance mismatch, amplifier noise and parasitic capacitance limit sensitivity.
Research and simulation exercise
Simulate reflectometry response to a capacitance shift.
Connect the ideas
Explore the chapter overview, learning path, and references.