A
radio frequency probe circuit comprises an
alternating current extraction module, an impedance conversion module, a
voltage amplification module and an output module, the
alternating current extraction module extracts
alternating current components of a preset
frequency band in a
signal to be detected, so that the frequency of the
signal to be detected can be selected;
voltage amplitude amplification is carried out on a first alternating current
signal in signals to be detected through the
voltage amplification module so as to offset
signal gain attenuation caused in the
coaxial cable signal transmission process, in addition, in order to not affect
signal amplification of the voltage amplification module, the
output impedance of the voltage amplification module is adjusted to be matched with the voltage amplification module through the impedance conversion module, and the
output impedance of the voltage amplification module is adjusted to be matched with the
output impedance. The output impedance is adjusted in the output module to be matched with the
characteristic impedance of the
coaxial cable, so that the
characteristic impedance is matched with the
input impedance of the
radio frequency equipment; therefore, the
radio frequency probe circuit provided by the utility model not only can transmit the to-be-detected signal of the predetermined
frequency band under the condition that the
gain is not changed, but also can perform impedance adjustment.