Abstract: A radio frequency (RF) coil comprises a lay-out of electrical conductors including several axial rung 11s and several circumferential rings (12), in which at least one of the rung 11s is coupled with at least one of the rings by a T-shaped connector. The T-shaped connector includes a distributed capacitive coupling between the ring (12) and the rung (11).

Abstract: A magnetic resonance radio frequency transmission device (140) for generating and applying a radio frequency excitation field B1 for the purpose of magnetic resonance examination comprises a birdcage coil (144) and a plurality of M radio frequency amplifier units for providing radio frequency power at a magnetic resonance frequency to the birdcage coil (144) via a plurality of M activation ports (158) selected out of the plurality of N activation ports (158). In an operational state of the birdcage coil (144) each radio frequency amplifier unit (142) is electrically connected and is arranged in close proximity to an activation port (158).

Abstract: A magnetic resonance radio frequency transmission device (140) for generating and applying a radio frequency excitation field B1 for the purpose of magnetic resonance examination comprises a birdcage coil (144) and a plurality of M radio frequency amplifier units for providing radio frequency power at a magnetic resonance frequency to the birdcage coil (144) via a plurality of M activation ports (158) selected out of the plurality of N activation ports (158). In an operational state of the birdcage coil (144) each radio frequency amplifier unit (142) is electrically connected and is arranged in close proximity to an activation port (158).

Abstract: A radio frequency coil for transmitting or receiving signals at a magnetic resonance frequency includes an arrangement of substantially parallel rungs (70, 70?, 70?) and one or more generally annular strip-type end-rings (78, 78?, 78?, 80) disposed generally transverse to the parallel rungs and connected with the rungs. Each generally annular strip-type end-ring includes at least two conductor layers (82, 82?, 82?, 84, 84?, 84?, 86, 88) separated by a dielectric layer (72, 72a, 72b). A radio frequency shield (34) substantially surrounds the arrangement of substantially parallel rungs (70, 70?, 70?). At least one of the conductor layers of each end-ring is connected with the radio frequency shield.

Abstract: A radio frequency coil for transmitting or receiving signals at a magnetic resonance frequency includes an arrangement of substantially parallel rungs (70, 70?, 70?) and one or more generally annular strip-type end-rings (78, 78?, 78?, 80) disposed generally transverse to the parallel rungs and connected with the rungs. Each generally annular strip-type end-ring includes at least two conductor layers (82, 82?, 82?, 84, 84?, 84?, 86, 88) separated by a dielectric layer (72, 72a, 72b). A radio frequency shield (34) substantially surrounds the arrangement of substantially parallel rungs (70, 70?, 70?). At least one of the conductor layers of each end-ring is connected with the radio frequency shield.

Abstract: A magnetic resonance imaging system (10) utilizes an ultra-short RF body coil (36). The ultra-short body coil (36) is shorter than the mechanical equivalent birdcage coil by at least a factor of two. Such coil provides equivalent (Bt) magnetic field-uniformity, while conforming to SAR limitations.

Abstract: A combiner/splitter device (100) comprises two transmission lines (23, 24), wound to form a helical coil (55), this helical coil being bent to a toroidal shape. Furthermore, a capacitor (51) is provided, connected in parallel with the two outer conductors (25, 26) of the two transmission lines (23, 24). The combination of the wound transmission lines and said capacitor forms a parallel resonator (56). The combiner/splitter device is suitable for use in a magnetic resonance imaging (MRI) system to combine the output signals of a receiver coil system and/or to split the input signal of a transmission coil system used in the MRI system.

Abstract: A radio-frequency coil (RF-coil) (19) for use in a magnetic-resonance imaging apparatus comprises a number of parallel bar-shaped electric conductors (37) arranged at regular intervals on an imaginary cylinder (39) and surrounded by a radio-frequency shield (RF-shield) (49). The bar-shaped conductors surround a measuring volume (11) and are interconnected at least at one of their end portions (41, 45) by an electric end conductor (43, 47) extending in a plane transverse to the bar-shaped conductors. A further electric end conductor (51, 53) is arranged near and parallel to the end conductor (43, 47), and is electrically connected to the RF-shield (49), preferably by a flange-shaped electric conductor (55, 57). The end conductor (43, 47) and the further end conductor (51, 53) together form a transmission line.

Abstract: A combiner/splitter device (100) comprises two transmission lines (23, 24), wound to form a helical coil (55), this helical coil being bent to a toroidal shape. Furthermore, a capacitor (51) is provided, connected in parallel with the two outer conductors (25, 26) of the two transmission lines (23, 24). The combination of the wound transmission lines and said capacitor forms a parallel resonator (56). The combiner/splitter device is suitable for use in a magnetic resonance imaging (MRI) system to combine the output signals of a receiver coil system and/or to split the input signal of a transmission coil system used in the MRI system.

Abstract: The invention relates to a radio-frequency coil (RF-coil) (19) for use in a magnetic-resonance imaging apparatus. The RF-coil comprises a number of parallel bar-shaped electric conductors (37), which are arranged at regular intervals on an imaginary cylinder (39) and which are surrounded by a radio-frequency shield (RF-shield) (49). The bar-shaped conductors surround a measuring volume (11) of the device and are interconnected at at least one of their end portions (41, 45) by means of an electric end conductor (43, 47) extending in a plane transverse to the bar-shaped conductors.

Abstract: The invention relates to a resonance trap (8) for suppressing electromagnetic coupling phenomena for a line (1), which resonance trap includes a conductor (10) which extends parallel to and along a part of the length of the line (1). Conventional resonance traps (8) have the drawback that a direct connection exists between the RF line and the individual resonance traps (8). It is an object of the invention to provide a resonance trap (8) which enables a modular assembly on the line (1). The object is achieved by means of a resonance trap (8) of the kind set forth in which inner conductors (10) extend parallel to the line (1) and in which outer conductors (11) extend parallel to the inner conductors (10), said inner conductors (10) being arranged at a radial distance from the line (1) which is smaller than that at which the outer conductors (11) are arranged and the outer conductors (11) being arranged to cover at least partly the inner conductors (10) in the radial direction relative to the line (1).

Abstract: The invention relates to a resonance trap (8) for suppressing electromagnetic coupling phenomena for a line (1), which resonance trap includes a conductor (10) which extends parallel to and along a part of the length of the line (1). Conventional resonance traps (8) have the drawback that a direct connection exists between the RF line and the individual resonance traps (8). It is an object of the invention to provide a resonance trap (8) which enables a modular assembly on the line (1). The object is achieved by means of a resonance trap (8) of the kind set forth in which inner conductors (10) extend parallel to the line (1) and in which outer conductors (11) extend parallel to the inner conductors (10), said inner conductors (10) being arranged at a radial distance from the line (1) which is smaller than that at which the outer conductors (11) are arranged and the outer conductors (11) being arranged to cover at least partly the inner conductors (10) in the radial direction relative to the line (1).

Abstract: An integrated circuit comprising a cascode current mirror and a bias stage for biassing the cascode current mirror, the cascode current mirror comprising, between an input terminal (11) and a supply voltage terminal (14), a first cascoded MOS transistor (21) and a first cascode MOS transistor (22) and, between an output terminal (12) and the supply voltage terminal (14), a second cascoded MOS transistor (23) and a second cascode MOS transistor (24).

Abstract: A relates to a band-gap reference-voltage arrangement includes a MOS differential amplifier (OA2) having two inputs and one output. A first bipolar transistor (Q3) has its base/emitter path coupled between one input of the differential amplifier and a specific junction point and has an emitter-collector path arranged in a first current path for carrying a first current. A second bipolar transistor (Q4) has its base/emitter path connected in series with a resistor (R6) between the other input of the differential amplifier and said junction point and has its emitter-collector path arranged in a second current path for carrying a second current. First and second transistors (P1), P2) supply said first and second currents to the first and second current paths.

Abstract: A voltage-current converter includes a first current-source (I.sub.1) coupled by means of a diode-arranged first transistor (T.sub.1) to a first terminal (1) at reference potential and by means of a diode-arranged second transistor (T.sub.2) to a second terminal (2). The bases of a third (T.sub.3) and a fourth (T.sub.4) transistor are coupled to the first (1) and the second (2) terminal, respectively. The emitters of these transistors (T.sub.3,T.sub.4) are coupled to a second current source (I.sub.2). A voltage source (V) and a resistor (R.sub.1) for converting the voltage (V) into a signal current are arranged between the first (1) and the second (2) terminal. The signal current is amplified by the translinear-circuit of the first, second, third and fourth transistors (T.sub.1 -T.sub.4) and fed to the outputs (30,40) via cascode transistors (T.sub.9,T.sub.10). To correct the non-linearity in the voltage-current conversion due to the non-linear emitter resistors of the first (T.sub.1) and the second (T.sub.