Dual frequency surface probes

A radio frequency (RF) surface probe for use in magnetic resonance (MR) systems with transmitter means for transmitting RF pulses which cause samples under test to emit RF signals and with receiver means for receiving said RF signals, the transmitter means and the receiver means having a characteristic impedance, said signals providing data for imaging and/or spectrograph purposes, said probe resonating at least at a first frequency and a second frequency, said probe comprising:

• (a) a plurality of inductance means for transmitting said RF pulses to said samples and for receiving said RF signals from said samples;
• (b) reactance means for connecting together said plurality of inductance means to form a balanced probe circuit having virtual short circuit planes that minimize electrostatic coupling between the probe and a given sample and thereby minimize loading of the probe by the given sample and enabling the probe to be used with different samples and/or spacing between the given sample and the probe without the necessity of retuning to maintain resonance at the first frequency and at the at least second frequency;
• (c) first connecting means for connecting said balanced probe circuit to said transmitter means and said receiver means and to cause said plurality of inductance means and said reactance means to match said characteristic impedance and to resonate at said first frequency;
• and
• (d) second connecting means for connecting said balanced probe circuit to said transmitter means and said receiver means and to cause said plurality of inductance means and reactance means to match said characteristic impedance and to resonate at said second frequency.