Abstract: A microwave power amplifier arrangement for an electron paramagnetic resonance (EPR) system provides amplified microwave pulses having a microwave frequency in the X-band. The arrangement has a microwave input and a microwave output, and comprises at least one transistor amplifier device, and at least one switchable reflection device. A respective transistor amplifier device comprises a transistor amplifier device input directly or indirectly connected to the microwave input (2), at least one transistor, and a transistor amplifier device output directly or indirectly connected to the microwave output. A respective switchable reflection device comprises a PIN diode and a lambda/4 line connected directly or indirectly to the transistor amplifier device output of at least one transistor amplifier device and to a first port of the PIN diode, with lambda being the wavelength of the microwave radiation within the lambda/4 line. A second port of the PIN diode is connected to ground.

Abstract: A method for determining an electric current includes sending the electric current to be measured through a shunt arrangement that includes at least three identical resistors. The at least three identical resistors are thermally coupled to a common base plate and are electrically interconnected such that the electric current is at least partially divided such that a first local current through a first resistor is not equal to a second local current through a second resistor. The method also includes measuring, at the shunt arrangement, a first voltage and a second voltage via which the voltage dropping across a first resistor and across a second resistor are directly or indirectly determinable, and determining the electric current via the first voltage and the second voltage. A heating in the shunt arrangement generated by the electric current is at least partially taken into account in the determining the electric current.

Abstract: A method for determining an electric current includes sending the electric current to be measured through a shunt arrangement that includes at least three identical resistors. The at least three identical resistors are thermally coupled to a common base plate and are electrically interconnected such that the electric current is at least partially divided such that a first local current through a first resistor is not equal to a second local current through a second resistor. The method also includes measuring, at the shunt arrangement, a first voltage and a second voltage via which the voltage dropping across a first resistor and across a second resistor are directly or indirectly determinable, and determining the electric current via the first voltage and the second voltage. A heating in the shunt arrangement generated by the electric current is at least partially taken into account in the determining the electric current.

Abstract: A microwave bridge circuit routes a transmission signal from a transmitter to a resonator and forwards the reception signal generated in the resonator to a receiver. It includes two electrical lines connected in parallel at a first circuit point TX, where the transmission signal is divided. The first electrical line has an attenuator for attenuating a first transmission signal portion. The second electrical line carries a second transmission signal portion and connects to the resonator at a second circuit point R, which divides it between section L1, which runs from TX to R, and section L2, which runs from R to a third circuit point RX. The length of the sections L1 and L2 corresponds to an odd integer multiple of one quarter of the wavelength of the transmission signal, and the divided transmission signal portions are combined at RX, where the reception signal is forwarded to the receiver.

Abstract: A high-frequency interface circuit to direct transmitted signals to a connector (PR) for a HF arrangement in a transmit mode via an input (TX) of the high-frequency interface circuit and received signals from the connector (PR) to a receiver system in a receive mode via an output (RX) of the high-frequency interface circuit is presented. The circuit includes a transmit path (SP) linking the input (TX) to the connector (PR) and a receive path (EP) linking the connector (PR) to the output (RX). The receive path (EP) includes a first circuit (K1), with at least a first switching element (S1) that is electro-conductive in transmit mode and is electrically insulating in receive mode, connected to the connector (PR). In transmit mode, the first circuit (K1) forms two parallel resonance circuits connected in series, while in receive mode, the first circuit (K1) includes two series resonance circuits connected in parallel.

Abstract: A magnetic resonance (MR) device, having a gradient arrangement that includes a gradient coil (G) with an internal resistance (Rg), as well as an electric circuit for generating variable pulse-shaped currents through the gradient arrangement. The electric circuit has at least one low-voltage voltage source (V) for generating a voltage U?100V, and a first circuit section in the electric circuit for current in the gradient coil in one direction and a second circuit section in the electric circuit for current in the gradient coil in a reverse direction to the first circuit section. This permits the generation of accurate square-wave current pulses, with a simultaneously short charging time of the auxiliary inductance.

Abstract: A magnetic resonance (MR) device, having a gradient arrangement that includes a gradient coil (G) with an internal resistance (Rg), as well as an electric circuit for generating variable pulse-shaped currents through the gradient arrangement. The electric circuit has at least one low-voltage voltage source (V) for generating a voltage U?100V, and a first circuit section in the electric circuit for current in the gradient coil in one direction and a second circuit section in the electric circuit for current in the gradient coil in a reverse direction to the first circuit section. This permits the generation of accurate square-wave current pulses, with a simultaneously short charging time of the auxiliary inductance.

Abstract: A high-frequency interface circuit to direct transmitted signals to a connector (PR) for a HF arrangement in a transmit mode via an input (TX) of the high-frequency interface circuit and received signals from the connector (PR) to a receiver system in a receive mode via an output (RX) of the high-frequency interface circuit is presented. The circuit includes a transmit path (SP) linking the input (TX) to the connector (PR) and a receive path (EP) linking the connector (PR) to the output (RX). The receive path (EP) includes a first circuit (K1), with at least a first switching element (S1) that is electro-conductive in transmit mode and is electrically insulating in receive mode, connected to the connector (PR). In transmit mode, the first circuit (K1) forms two parallel resonance circuits connected in series, while in receive mode, the first circuit (K1) includes two series resonance circuits connected in parallel.

Abstract: A nuclear magnetic resonance (NMR) resonator (1; 31) comprising an inductive section (6) and a capacitive section (6a), wherein the inductive section (6) is band-shaped and surrounds a substantially cylindrical volume under investigation (5), wherein the capacitive section (6a) is formed from one or more discrete capacitor(s) (13; 13a, 13b, 13c, 13d), and wherein the ends (7, 8) of the band-shaped inductive section (6) are connected through one or several capacitor(s) (13; 13a, 13b, 13c, 13d) of the capacitive section (6a), is characterized in that the inductive section (6) is formed from a dielectric flexible foil (2) which is conductively coated on both sides and the ends (7, 8) of the band-shaped inductive section (6) overlap, wherein the outer coating (4) of the inner end (7) is electrically conductingly connected to the inner coating (3) of the outer end (8), with one or more through-connections (10) being provided in the area of the inner end (7) of the band-shaped inductive section (6), and the outer c

Abstract: A nuclear magnetic resonance (NMR) resonator (1; 31) comprising an inductive section (6) and a capacitive section (6a), wherein the inductive section (6) is band-shaped and surrounds a substantially cylindrical volume under investigation (5), wherein the capacitive section (6a) is formed from one or more discrete capacitor(s) (13; 13a, 13b, 13c, 13d), and wherein the ends (7, 8) of the band-shaped inductive section (6) are connected through one or several capacitor(s) (13; 13a, 13b, 13c, 13d) of the capacitive section (6a), is characterized in that the inductive section (6) is formed from a dielectric flexible foil (2) which is conductively coated on both sides and the ends (7, 8) of the band-shaped inductive section (6) overlap, wherein the outer coating (4) of the inner end (7) is electrically conductingly connected to the inner coating (3) of the outer end (8), with one or more through-connections (10) being provided in the area of the inner end (7) of the band-shaped inductive section (6), and the outer c