Baluns, a fine balance and impedance adjustment module, a multi-layer transmission line, and transmission line NMR probes using same

• US 9,065,161 B2
• Filed: 03/22/2011
• Issued: 06/23/2015
• Est. Priority Date: 11/21/2007
• Status: Expired due to Fees

• Current Assignee: Brandeis University
• Original Assignee: Brandeis University
• Inventors: Hu, Jianping, Herzfeld, Judith
• Primary Examiner(s): Vargas, Dixomara
• Application Number:
  US13/065,446
• Publication Number:
  US 20110285397A1
• Time in Patent Office: 1,554 Days
• Field of Search: 324300-322, 600409-445
• US Class Current: 1/1
• CPC Class Codes: H01P 5/02 with invariable factor of coupling H01P5/12 takes precedence choke joints H01P1/04, H01P1/06
• CPC Class Codes: H01P 5/10 for coupling balanced lines or devices with unbalanced lines or devices

Abstract

A pseudo-Marchand balun, compound balun and tunable multi-resonant coaxial balun, and NMR probes employing each such balun, and a fine balance and impedance adjustment module and a multi-layer transmission line for use in such NMR probes.

Claims

1. A multi-resonant compound balun NMR probe comprising:

a base including at least one tuning and matching circuit; and

a probe body including a segmented main transmission line interconnected to said at least one tuning and matching circuit;

a multi-resonant compound balun connected to said main transmission line and a sample coil interconnected to said multi-resonant compound balun and wherein said multi-resonant compound balun includes a transmission line system having a center conductor and at least three concentric shields forming a first transmission line between said center conductor and said first shield, a second transmission line between said first and second shields, and a third transmission line between said second and third shields;

said first transmission line receiving unbalanced input/output at least three frequencies at one end and providing a multi-band balanced output/input at the other;

said second and third transmission lines forming a choke to suppress the common mode current in the shield of the first transmission line at high frequency.

2. The multi-resonant compound balun NMR probe of claim 1 further including in said base a common null point module interconnected between said at least one tuning and matching circuit and said main transmission line.

3. The multi-resonant compound balun NMR probe of claim 1 further including in said probe body a fine balance and impedance adjustment module interconnected between said multi-resonant compound balun and said sample coil.

4. A multi-resonant compound balun NMR probe comprising:

a base including at least one tuning and matching circuit; and

a multi-resonant compound balun interconnected therewith;

a probe body including a balanced pair of segmented main transmission lines at the proximate end and a sample coil at the distal end and wherein said multi-resonant compound balun includes a transmission line system having a center conductor and at least three concentric shields forming a first transmission line between said center conductor and said first shield, a second transmission line between said first and second shields, and a third transmission line between said second and third shields;

said first transmission line receiving multi-band unbalanced input/output at one end and providing balanced output/input at least three frequencies at the other end;

said second and third transmission lines forming a choke to suppress the common mode current in the shield of the first transmission line at high frequency.

5. The multi-resonant compound balun NMR probe of claim 4 further including a common null point module interconnected between said at least one tuning and matching circuit and said multi-resonant compound balun.

6. The multi-resonant compound balun NMR probe of claim 5 further including a fine balance and impedance adjustment module interconnected between said sample coil and said main transmission line.

7. The multi-resonant compound balun NMR probe of claim 4 further including a transmission line extension in series between a common point module and said multi-resonant compound balun.