NMR probe circuit for generating close frequency resonances

A method of generating a plurality of high frequency magnetic fields for a nuclear magnetic resonance probe, the method comprising:

• providing a probe circuit having a first resonator resonant at a frequency f1, a second resonator that has a magnetic field generating component and is resonant at a frequency f2 that is higher than f1, and a third resonator resonant at a frequency f3 that is higher than f2, the resonances of the three resonators giving rise to intermediate resonances at frequency f12, between frequencies f1 and f2, and frequency f23, between frequencies f2 and f3;
• and
• coupling a first signal at frequency f12 and a second signal at frequency f23 to the circuit such that magnetic fields are generated by the magnetic field generating element at frequency f12 and frequency f23.

A method for generating resonant magnetic fields at a first frequency f12 and a second frequency f23 that is higher than f12, the method comprising:

• providing a nuclear magnetic resonance (NMR) probe circuit comprising a first resonator resonant at a frequency f1 that is lower than f12, a second resonator having a magnetic field generating component from which the resonant magnetic fields originate, the resonator being resonant at a frequency f2 that is higher than f1 and f12, but lower than f23, and third resonator resonant at a frequency f3 that is higher than f23, wherein the first, second and third resonators are arranged in the circuit relative to one another such that they are in a parallel combination or in a combination that is the electrical equivalent of a parallel combination;
• and
• coupling a first signal at frequency f12 and a second signal at frequency f23 to the circuit such that magnetic fields are generated by the magnetic field generating element at frequency f12 and frequency f23.