Wideband Probe for Magnetic Quadrupole Resonance Spectroscopy

Aim of this paper is the custom design of a lowcost nuclear quadrupole resonance spectrometer (NQR)applying a commercial network analyzer (NWA), an RF power amplifier, a RX/TX switching unit and a wideband probe with a small sample volume of no more than 1 cm. The probe was designed as an appropriately terminated exponential transmission line approximated with 5 lumped LC-pi-sections. The last section contains the probe coil. The measured S11 of the probe remains below -20dB within a bandwidth of 55 MHZ between 90 MHz and 145 MHz.