Abstract: A parametric amplifier device has a two port parametric amplifier, a DC voltage generator and a DC bias regulator. The bias regulator has a voltage regulator, an attenuator and a summer. Output voltages from the regulator and the attenuator are added in the summer.

Abstract: A magnetic resonance imaging system upconverter stage has a number of local coils and a number of upconverters to receive a signal from an output of each coil. Each upconverter has a number of two port upconverter cores, each core having a first port to receive a signal from a local coil and a second port to output an upconverted signal at upper and lower sideband frequencies through an antenna coupled to the second port. The inputs of the plurality of upconverter cores are connected in parallel, and at least one antenna is associated with the second port of each core.

Abstract: A hybrid upconverter has a low noise amplifier and a two port parametric amplifier. The parametric amplifier has a first port to receive an input signal to be amplified and upconverted and a second port to receive a local oscillator signal and to output the amplified, upconverted signal at upper and lower sideband frequencies. The parametric amplifier further has an antenna coupled to the second port to receive the local oscillator signal and transmit the amplified, upconverted signal at upper and lower sideband frequencies. The low noise amplifier drives the first port of the parametric amplifier. The two port parametric amplifier has a pair of varactor diodes connected between the first port and the second port. The diodes are connected in parallel from the first port and in series from the second port. The low noise amplifier is connected directly to the pair of varactor diodes.

Abstract: A two port parametric amplifier has a first port that receives an input signal to be amplified and upconverted and a second port that receives a local oscillator signal. The amplified upconverted input signal is emitted as an output at upper and lower sideband frequencies. The amplifier further has a pair of varactor diodes connected between the first port and the second port. The diodes are connected in parallel from the first port and in series from the second port.

Abstract: A wireless magnetic resonance imaging (MRI) scanner bore tube assembly has a radio frequency (RF) antenna, a microwave antenna array and an electrical screen. The RF antenna is formed of a series of RF antenna elements, each comprising a rung. The rungs are spaced at intervals of substantially half of the wavelength of the frequency of operation of the microwave antenna array. The microwave antenna array is formed by a series of microwave antenna elements interleaved between the rungs and the screen acts as a reflector to reflect signals from the microwave antenna elements towards the center of the bore tube.

Abstract: A hybrid upconverter has a low noise amplifier and a two port parametric amplifier. The parametric amplifier has a first port to receive an input signal to be amplified and upconverted and a second port to receive a local oscillator signal and to output the amplified, upconverted signal at upper and lower sideband frequencies. The parametric amplifier further has an antenna coupled to the second port to receive the local oscillator signal and transmit the amplified, upconverted signal at upper and lower sideband frequencies. The low noise amplifier drives the first port of the parametric amplifier. The two port parametric amplifier has a pair of varactor diodes connected between the first port and the second port. The diodes are connected in parallel from the first port and in series from the second port. The low noise amplifier is connected directly to the pair of varactor diodes.

Abstract: A parametric amplifier device has a two port parametric amplifier, a DC voltage generator and a DC bias regulator. The bias regulator has a voltage regulator, an attenuator and a summer. Output voltages from the regulator and the attenuator are added in the summer.

Abstract: A magnetic resonance imaging system upconverter stage has a number of local coils and a number of upconverters to receive a signal from an output of each coil. Each upconverter has a number of two port upconverter cores, each core having a first port to receive a signal from a local coil and a second port to output an upconverted signal at upper and lower sideband frequencies through an antenna coupled to the second port. The inputs of the plurality of upconverter cores are connected in parallel, and at least one antenna is associated with the second port of each core.

Abstract: A two port parametric amplifier has a first port that receives an input signal to be amplified and upconverted and a second port that receives a local oscillator signal. The amplified upconverted input signal is emitted as an output at upper and lower sideband frequencies. The amplifier further has a pair of varactor diodes connected between the first port and the second port. The diodes are connected in parallel from the first port and in series from the second port.

Abstract: A wireless magnetic resonance imaging (MRI) scanner bore tube assembly has a radio frequency (RF) antenna, a microwave antenna array and an electrical screen. The RF antenna is formed of a series of RF antenna elements, each comprising a rung. The rungs are spaced at intervals of substantially half of the wavelength of the frequency of operation of the microwave antenna array. The microwave antenna array is formed by a series of microwave antenna elements interleaved between the rungs and the screen acts as a reflector to reflect signals from the microwave antenna elements towards the centre of the bore tube.