Power is fed from a feeding coil L2 to a receiving coil L3 by magnetic resonance. A VCO 202 alternately turns ON/OFF switching transistors Q1 and Q2 at a drive frequency fo, whereby AC power is fed to the feeding coil L2, and then the AC power is fed from the feeding coil L2 to the receiving coil L3. A phase detection circuit 114 detects a phase difference between the current phase and voltage phase, and the VCO 202 adjusts the drive frequency fo such that the phase difference becomes zero. When load voltage is changed, the detected current phase value is adjusted with the result that the drive frequency fo is adjusted.

Wireless power feeder, wireless power receiver, and wireless power transmission system

A probe (80) for irradiating a sample with RF energy during transmitting periods and detecting an NQR or NMR signal from a substance contained within the sample during receiving periods. The probe (80) comprises a variable impedance unit (20) for changing the Q-factor of the probe and a probe coil. The probe (80) is responsive to powerful RF pulses applied thereto to excite RF magnetic field in the probe coil during the transmitting periods. The impedance (20) is controllable to provide a Q-factor for the probe (80) at: an optimal level during a prescribed transmitting period of an RF pulse for irradiating the sample with said RF energy; a minimal level during a prescribed recovery period immediately following said transmitting period to rapidly dampen transient signals from the probe; and a maximal level during a prescribed receiving period for detecting an NQR or NMR signal from the target substance if present, immediately following the recovery period.

Q-factor switching method and apparatus for detecting nuclear quadrupole and nuclear magnetic resonance signals

This invention relates to the use of a nuclear quadrupole resonance detection system for detecting contraband, wherein the detection system comprises a container with a detection panel and at least one coil for exciting and detecting the nuclear quadrupole resonance frequencies of a contraband source placed near an outer side of the detection panel.

Detection of contraband using nuclear quadrupole resonance

The use of a circuit to adjust the resonance frequency of a high temperature superconductor self-resonant transmit, receive, or transmit and receive coil results in improved performance. The circuit is useful in a frequency detection system, especially in a nuclear quadrupole resonance detection system.

Frequency detection system comprising circuitry for adjusting the resonance frequency of a high temperature superconductor self-resonant coil

An antenna and shield apparatus for detecting phenomenal signals using nuclear and electronic resonance detection technology, comprising: a transmit and receive antenna, an electric field shield (60) and an outer shield (52). The antenna is a multiple parallel loop transmit-receive antenna forming a main coil assembly (11) having a plurality of loop segments (20) optionally interconnected by connectors in the form of conducting bars (10), relays (16), or nothing. The electric field shield (60) comprises an inner sleeve of conducting material (60, 68) disposed on the inside of the coil assembly (11) for shielding the electric field emanating from the coil assembly (11) from the target volume circumscribed by the assembly. The outer shield (52) comprises a central screen portion (55), waveguides (57) at either end thereof and a sloping channel portion for interconnecting the two. The coil assembly 11 and the electric field shield (60) are housed within the outer shield (52).

Transmit - receive coil system for nuclear quadrupole resonance signal detection in substances and components thereof

A Q-damping subsystem for either an NQR or NMR contraband detection receiver for effectively reducing the dead time and increasing sensitivity of the contraband detection system. The invention acts as an addition to the standard transmit circuits of NQR and NMR based scanners and spectrometers. The active Q-damping devices require additional circuitry for an NQR/NMR detection receiver and a programming for the control thereof. Typically, the detection receiver generates a high-voltage RF pulse on the order of 200-1000 V with normal operation of 100-300 microseconds in length to provide sufficient magnetic field characteristics to perturb the precessing nuclei. The NQR or NMR detection receiver electronics are very sensitive and have to detect a very weak nuclear induction pulse signal that is in the nano/micro-volt range. The invention encompasses several embodiments of the detection receiver with the Q-damping subsystem which include: a transformer coupled resistive damping circuit; an inductively coupled resistive damping circuit; a shunt capacitor/resistor damping circuit; a grounded shunt capacitor/resistor damping circuit; a common mode choke transient suppression damping circuit; a multi-stage Q-damping circuit; and a full-wave Q-damping circuit.

Yong-Wah Kim

Papers

Active Q-damping sub-system using nuclear quadrupole resonance and nuclear magnetic resonance for improved contraband detection