Compact step-programmable optimization of low-noise amplifier signal-to-noise

• Main Author: CLIFF RICHARD
• Format: Patent
• Language: English
• Published: 04.12.2014
• Subjects: BASIC ELECTRIC ELEMENTS; BLASTING; CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES ORLIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE; ELECTRICITY; ENGINEERING ELEMENTS AND UNITS; GEARING; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HEATING; INDUCTANCES; LIGHTING; MAGNETS; MECHANICAL ENGINEERING; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; THERMAL INSULATION IN GENERAL; TRANSFORMERS; WEAPONS

A new family of programmable low-noise RF impedance transformers has been developed. These new transformers can be configured and operated to compensate for variable antenna output impedance. This enables better optimization of RF receiving-system SNR. For some applications, these new devices can be more compact and less expensive than any previously available. In particular, such new transformers can improve MRI system performance. This requires additional new art because MRI systems demand components which are not ferromagnetic, which do not produce spurious MR signals and which add very little noise to received RF signals. In various embodiments, these new transformers are comprised of remotely-controlled variable capacitors and inductors which are connected in networks between antenna element outputs and their following LNA inputs. These new step-programmable inductors and capacitors can be either electrically or pneumatically actuated. Pneumatic or electrostatic actuation will in general be particularly useful for application in MRI systems.