Magnetic Spectrometer

My first project in ACME research lab was to build a magnetic spectrometer on a PCB. It is essentially a LC tank with a capacitor bank to vary frequency and a cross-coupled transistor pair. If magnetic nanoparticles are placed within the planar inductor, the resonant frequency of the LC tank shifts. The frequency is measured with a differential amplifier op amp circuit. Measuring the frequency shift over a range of frequencies provides a characterization of the specific magnetic nanoparticle. I designed the PCB in KiCAD and simulated it in Ansys HFSS for S-parameters and LTSpice to verify functionality.

Scuffed testing setup

Oscilloscope output

Initial oscillator prototype on breadboard