# US 10,502,798 B2 · High-frequency interface circuit, high-frequency system and magnet resonance apparatus with a high-frequency interface circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,798 B2 - Document ID: US10502798B2 - Status: Granted - Kind: B2 - Application number: 15/669,465 - Filed: 2017-08-04 - Published: 2018-02-08 - Granted: 2019-12-10 - Earliest claimed: 2016-08-04 - Assignees: Bruker BioSpin GmbH - Applicants: Bruker BioSpin GmbH - Inventors: Michael Maixner - Web page: https://patentgrep.com/patent/US10502798B2 ## CPC - G01R 33/3657: {Decoupling of multiple RF coils wherein the multiple RF coils do not have the same function in MR, e.g. decoupling of a transmission coil from a receive coil} - G01R 33/36: Electrical details, e.g. matching or coupling of the coil to the receiver - G01R 33/3628: {Tuning/matching of the transmit/receive coil} - G01R 33/3607: {RF waveform generators, e.g. frequency generators, amplitude-, frequency- or phase modulators or shifters, pulse programmers, digital to analog converters for the RF signal, means for filtering or attenuating of the RF signal} - G01R 33/3621: {NMR receivers or demodulators, e.g. preamplifiers, means for frequency modulation of the MR signal using a digital down converter, means for analog to digital conversion [ADC] or for filtering or processing of the MR signal such as bandpass filtering, resampling, decimation or interpolation} - G01R 33/3642: {Mutual coupling or decoupling of multiple coils, e.g. decoupling of a receive coil from a transmission coil, or intentional coupling of RF coils, e.g. for RF magnetic field amplification} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## 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. ## Claims ### Claim 1 A high-frequency (HF) interface circuit comprising: a connector (PR) that links to a HF arrangement, a transmit path (SP) which links an input (TX) of the high-frequency interface circuit to the connector (PR), wherein the input (TX) receives signals transmitted by a HF generator; a receive path (EP) that links the connector (PR) to an output (RX) of the high-frequency interface circuit, whereby the receive path (EP) includes a first circuit (K1) and wherein the output (RX) directs signals to a receiver system, whereby the first circuit (K1) includes at least a first switching element (S1) that is electro-conductive in transmit mode and electrically insulating in receive mode, whereby, in the transmit mode, the first circuit (K1) forms first and second parallel resonance circuits connected in series that isolate the output (RX) of the high-frequency interface circuit from the connector (PR); wherein in the receive mode, the first circuit (K1) includes first and second series resonance circuits connected in parallel wherein the receive path (EP) further includes a second grounding switching element (S2) that is electro-conductive in the transmit mode and electrically insulating in the receive mode. ### Claim 2 (depends on 1) The high-frequency interface circuit as claimed in claim 1, wherein the first circuit (K1) comprises a first inductive element (L1), a second inductive element (L2), a first capacitive element (C1) and a second capacitive element (C2), in the transmit mode, the second capacitive element (C2) together with the first inductive element (L1) and the first capacitive element (C1) together with the second inductive element (L2) form, respectively, the first and the second parallel resonance circuits of the first circuit (K1) and the first switching element (S1) is part of both the first and the second parallel resonance circuits, and in the receive mode, the second capacitive element (C2) together with the second inductive element (L2) and the first capacitive element (C1) together with the first inductive element (L1) form, respectively, the first and the second series resonance circuits of the first circuit (K1). ### Claim 3 (depends on 1) The high-frequency interface circuit as claimed claim 1, wherein the second switching element (S2) in the receive path (EP) is positioned directly before the output (RX) of the high-frequency interface circuit. ### Claim 4 (depends on 1) The high-frequency interface circuit as claimed in claim 1, wherein the transmit path (SP) includes an input-isolator circuit with a fourth switching element (S4) that is electro-conductive in the transmit mode and electrically insulating in the receive mode. ### Claim 5 (depends on 4) The high-frequency interface circuit as claimed in claim 4, wherein the input-isolator circuit is a HF filter in the transmit mode. ### Claim 6 (depends on 1) A high-frequency system with a HF generator generating HF signals, a HF arrangement that is configured to send and detect HF signals, a receiver system that is configured to process the detected HF signals and a high-frequency interface circuit as claimed in claim 1, whereby the HF generator is connected to the input (TX) of the high-frequency interface circuit, the receiver system is connected to the output (RX), and the HF arrangement is connected to the connector (PR) of the high-frequency interface circuit. ### Claim 7 (depends on 1) A magnetic resonance apparatus with a HF arrangement that excites magnetic resonances and receives MR signals and with the high-frequency interface circuit as claimed in claim 1. ### Claim 8 (depends on 7) The magnetic resonance apparatus as claimed in claim 7, wherein the HF arrangement is an MR probe. ### Claim 9 (depends on 1) The use of the high-frequency interface circuit as claimed in claim 1 in a magnetic resonance apparatus that performs multi-resonance MR measurements. ### Claim 10 (depends on 3) The high-frequency interface circuit as claimed in claim 3, wherein the receive path (EP) includes a second circuit (K2) that is connected to the first circuit (K1) in series, whereby the second switching element (S2) is part of the second circuit (K2), and whereby the second circuit (K2) forms a low pass filter in the receive mode and a third parallel resonance circuit in the transmit mode. ### Claim 11 (depends on 1) The high-frequency interface circuit as claimed in claim 1, wherein the interface circuit is in the transmit mode when the first switching element (S1) is closed, and wherein the interface circuit is in the receive mode when the first switching element (S1) is open. ### Claim 12 A high-frequency (HF) interface circuit to direct signals transmitted by a HF generator to a connector (PR) for a HF arrangement in a transmit mode via an input (TX) of the high-frequency interface circuit and to direct received signals from the connector (PR) of the HF arrangement to a receiver system in a receive mode via an output (RX) of the high-frequency interface circuit, whereby the interface circuit comprises: a transmit path (SP) which links the input (TX) of the high-frequency interface circuit to the connector (PR); a receive path (EP) that links the connector (PR) to the output (RX) of the high-frequency interface circuit, whereby the receive path (EP) includes a first circuit (K1), wherein the first circuit (K1) comprises a first inductive element (L1), a second inductive element (L2), a first capacitive element (C1), and a second capacitive element (C2), whereby the first circuit (K1) includes at least a first switching element (S1) that is electro-conductive in the transmit mode and electrically insulating in the receive mode, such that the first switching element (S1) is part of both first and second parallel resonance circuits of the first circuit (K1), whereby, in the transmit mode, the first circuit (K1) forms the first and the second parallel resonance circuits connected in series that isolate the output (RX) of the high-frequency interface circuit from the connector (PR), wherein the second capacitive element (C2) together with the first inductive element (L1) and the first capacitive element (C1) together with the second inductive element (L2) form, respectively, the first and the second parallel resonance circuits of the first circuit (K1), and wherein in the receive mode, the first circuit (K1) includes the first and the second series resonance circuits connected in parallel, wherein the second capacitive element (C2) together with the second inductive element (L2) and the first capacitive element (C1) together with the first inductive element (L1) form, respectively, the first and the second series resonance circuits of the first circuit (K1), and wherein the receive path (EP) includes a second grounding switching element (S2) that is electro-conductive in the transmit mode and electrically insulating in the receive mode, and wherein the receive path (EP) includes a second circuit (K2) that is connected to the first circuit (K1) in series, whereby the second switching element (S2) is part of the second circuit (K2), and whereby the second circuit (K2) forms a low pass filter in the receive mode and a third parallel resonance circuit in the transmit mode. ### Claim 13 (depends on 12) The high-frequency interface circuit as claimed in claim 12, wherein the second circuit (K2) includes a third inductive element (L3) and a third capacitive element (C3) that together form part of the third parallel resonance circuit in the transmit mode and part of the low pass filter in the receive mode. ### Claim 14 (depends on 12) The high-frequency interface circuit as claimed in claim 12, wherein the second circuit (K2) additionally includes a fourth capacitive element (C4) and a third grounding switching element (S3) that is electro-conductive in the transmit mode and electrically insulating in the receive mode, whereby, in the transmit mode, the fourth capacitive element (C4) is part of the third parallel resonance circuit. ### Claim 15 (depends on 12) The high-frequency interface circuit as claimed in claim 12, wherein the second circuit (K2) additionally includes a fifth capacitive element (C5) that is located parallel to the second switching element (S2) and is part of the low pass filter in the receive mode. ### Claim 16 (depends on 13) The high-frequency interface circuit as claimed in claim 13, wherein the inductance of the third inductive element (L3) is half as big as the inductance of the first inductive element (L1) or the second inductive element (L2). ### Claim 17 (depends on 13) The high-frequency interface circuit as claimed in claim 13, wherein the second circuit (K2) additionally includes a fourth capacitive element (C4) and a third grounding switching element (S3) that is electro-conductive in the transmit mode and electrically insulating in the receive mode, whereby, in the transmit mode, the fourth capacitive element (C4) is part of the third parallel resonance circuit. ### Claim 18 (depends on 13) The high-frequency interface circuit as claimed in claim 13, wherein the second circuit (K2) additionally includes a fifth capacitive element (C5) that is located parallel to the second switching element (S2) and is part of the low pass filter in the receive mode. ### Claim 19 (depends on 14) The high-frequency interface circuit as claimed in claim 14, wherein the second circuit (K2) additionally includes a fifth capacitive element (C5) that is located parallel to the second switching element (S2) and is part of the low pass filter in the receive mode. ### Claim 20 (depends on 14) The high-frequency interface circuit as claimed in claim 14, wherein the inductance of the third inductive element (L3) is half as big as the inductance of the first inductive element (L1) or the second inductive element (L2). ### Claim 21 (depends on 15) The high-frequency interface circuit as claimed in claim 15, wherein the inductance of the third inductive element (L3) is half as big as the inductance of the first inductive element (L1) or the second inductive element (L2).