WAI LING WONG
Acupuncture at Araujo St, San Jose, CA

6735851, May 18, 2004

Jan 8, 2002

10/043622

Marco A. Romo - Castro Valley CA
Wai Ha Wong - San Jose CA

Varian, Inc. - Palo Alto CA

H01F 706

29606, 29 2541, 29 2542, 29605, 29598, 324318, 324319, 324320, 324321, 324322, 324309

Superconducting birdcage coil with low-pass and high-pass coil configurations are formed by using strips each with an elongated sapphire substrate with a layer of a high temperature superconductor (HTS) material grown in a wavy pattern over its entire length on one of its main surfaces. A low-pass coil is formed with a pair of ring elements made of an electrically conductive metal and a plurality of such strips arranged parallel to one another and interconnecting these ring elements at junctions which are spaced peripherally along each of the rings. At each of the junctions, the ring element and the HTS layer form a capacitance. A high-pass coil is formed by a plurality of such strips each with electrodes of the HTS material also grown at two end positions separated from each other on the other main surface of its sapphire substrates. These strips are arranged parallel to each other and sequentially around a central axis, each lying in a plane which includes the center axis. The electrodes and the HTS layers on mutually adjacent pairs of strips are closely in face-to-face relationship so as to serve as the ring part of a birdcage configuration containing capacitors.

6420871, Jul 16, 2002

Mar 2, 2001

09/798322

Wai Ha Wong - San Jose CA
Seiji Unno - Santa Clara CA
Weston A. Anderson - Palo Alto CA

Varian, Inc. - Palo Alto CA

G01V 300

324318, 324320, 324322

A multiple tuned birdcage coil structure has a plurality of birdcage coils arranged coaxially one inside another around a central axis. Each of the birdcage coils has two conductor rings separated along the central axis and a plurality of mutually separated and parallel linearly elongated conductor legs and generates B field which rotates around the central axis by a specified twist angle between the two rings. The twist angles of different ones of these birdcage coils are different by an integral multiple of 360 degrees such that the assembled birdcage coils are mutually inductively transparent. Such a multiple tuned birdcage coil structure may be formed by assembling individually prepared single tuned birdcage coils each having a specified twist angle with a cylindrically shaped insulating bodies in between. A double tuned birdcage coil structure with two birdcage coils may be produced by providing a single printed circuit substrate with metallic sheets laminated on an insulating sheet, etching the metallic sheets to form appropriate patterns, rolling the substrate into a cylindrical form and soldering together appropriate portions of ring-forming parts to form conductor rings directly connected to or capacitively coupled to spirally birdcage legs.

6369570, Apr 9, 2002

Dec 21, 2000

09/747818

Wai Ha Wong - San Jose CA
Subramaniam Sukumar - Union City CA

Varian, Inc. - Palo Alto CA

G01V 300

324318, 324320, 324307

A birdcage-like coil with a pair of electrically conductive ring elements separated in a longitudinal direction and interconnected by three longitudinally extending electrically conductive elongated strips, two of which are diametrically oppositely disposed and the third is azimuthally at 90E from both of them, can create an RF magnetic field gradient when driven in a certain resonance mode. A similarly structured birdcage-like coil with a fourth strip to have two diametrically oppositely disposed strips can create two switchable orthogonal magnetic field gradient by switching off a selected one of the strips and driving the coil in a certain mode. A coil for generating alternative a homogeneous field and selectably one of two orthogonal gradient fields is formed by sandwiching a prior art birdcage long-pass coil with a pair of such coils and by switching on and off suitable ones of the switches in the strips.

6377047, Apr 23, 2002

Jun 8, 2000

09/589847

Wai Ha Wong - San Jose CA
Marco A. Romo - Castro Valley CA

Varian, Inc. - Palo Alto CA

G01V 300

324318, 324322

Superconducting birdcage coil with low-pass and high-pass coil configurations are formed by using strips each with an elongated sapphire substrate with a layer of a high temperature superconductor (HTS) material grown in a wavy pattern over its entire length on one of its main surfaces. A low-pass coil is formed with a pair of ring elements made of an electrically conductive metal and a plurality of such strips arranged parallel to one another and interconnecting these ring elements at junctions which are spaced peripherally along each of the rings. At each of the junctions, the ring element and the HTS layer form a capacitance. A highpass coil is formed by a plurality of such strips each with electrodes of the HTS material also grown at two end positions separated from each other on the other main surface of its sapphire substrates. These strips are arranged parallel to each other and sequentially around a central axis, each lying in a plane which includes the center axis. The electrodes and the HTS layers on mutually adjacent pairs of strips are closely in face-to-face relationship so as to serve as the ring part of a birdcage configuration containing capacitors.

7791339, Sep 7, 2010

Sep 7, 2007

11/899706

Wai Ha Wong - San Jose CA, US
Richard Stacy Withers - Sunnyvale CA, US
Weston A. Anderson - Palo Alto CA, US

Varian, Inc. - Palo Alto CA

G01V 3/00

324307, 324309

A multimode resonator resonating at two or more frequencies is operated at cryogenic temperatures and composed of a superconducting material or a normal metal with a superconducting section serving as a RF superconducting switch. The multimode resonator is coupled to a NMR spectrometer and a RF switch power source, wherein its one frequency is selected to correspond to the operating frequency of the NMR spectrometer and at least a second frequency is tuned to a frequency of RF switch power source, unrelated to the spectrometer frequency, therefore power at this frequency does not perturb the operation of the spectrometer. When activated, the RF switch power source induces a current sufficient to approach or exceeds the critical current in one or more sections of the superconducting material of the multimode resonator, thereby increasing its resistance and reducing the Q factor of the multimode resonator.

6980000, Dec 27, 2005

Apr 29, 2003

10/425780

Wai Ha Wong - San Jose CA, US
Jimmy Leung - Fremont CA, US
Alexander Funk - Mountain View CA, US
Knut Mehr - San Francisco CA, US

Varian, Inc. - Palo Alto CA

G01V003/00

324318

NMR coils are formed from transmission line comprising a tuned LC circuit determined substantially from the distributed capacitance and inductance of the transmission line operated in common mode. Introduction of gaps staggered between opposite conductors of 2-conductor transmission line contribute a desired distributed capacitance with reduced effective inductance to sustain resonant behavior at higher frequency than achievable with conventionally tuned coils and with relaxation of dimensional constraints as the resonant half wavelength approaches coil dimensions.

2013008, Apr 4, 2013

Aug 13, 2012

13/584126

Alan R. RATH - Fremont CA, US
Wai Ha WONG - San Jose CA, US
Weston A. ANDERSON - Palo Alto CA, US

AGILENT TECHNOLOGIES, INC. - Loveland CO

G01R 33/48, G01R 33/341

324310, 324322

A magnetic resonance imaging (MRI) apparatus comprises a plurality of cylindrical electromagnetic coils arranged in a coaxial configuration around a sample region. The coils are used to capture resonance signals from a sample at different times according to a geometric echo effect. The measurements can then be combined to produce an MRI signal.

6236206, May 22, 2001

Apr 23, 1999

9/298619

Spencer C. Hartman - Millbrae CA
Wai Ha Wong - San Jose CA

Varian, Inc. - Palo Alto CA

G01V 300

324318

A birdcage coil is globally tuned by a tuning structure to maintain constant RF phase shift for each leg conductor of the birdcage while containing a load. The birdcage coil may be globally tuned by adjusting the capacitances or inductances in a symmetrical manner.

6100694, Aug 8, 2000

Feb 24, 1999

9/256939

Wai Ha Wong - San Jose CA

Varian, Inc. - Palo Alto CA

G01V 300

324318

A multiple tuned bird cage coil for providing a substantially uniform RF field in a cylindrical sample area of said coil and exhibiting at least two fundamental resonant frequencies comprises a plurality of leg conductors disposed spaced from an axis and at least three rings conductors disposed about the axis and coupled to the leg conductors to define the cylindrical sample area with the leg conductors. The ring conductors and the leg conductors define a low pass bird cage coil that shares a portion of each of the leg conductors with a high pass bird cage coil. A higher frequency current and a lower frequency current flow through the shared portion of each of the leg conductors to provide the substantially uniform RF field in the cylindrical sample area.

2012015, Jun 21, 2012

Dec 15, 2010

12/969473

Wai Ha Wong - San Jose CA, US

AGILENT TECHNOLOGIES, INC. - Loveland CO

G01R 33/44

324322

According to one aspect, a magnetic resonance imaging (MRI) scanner includes a short birdcage (e.g. millipede) distributed-capacitance radio-frequency (RF) coil formed from one or more patterned planar conductive foils. The transverse extent (e.g. diameter) of the coil is at least a factor of 3, for example about a factor of 10, larger than the longitudinal (z-axis) extent of the coil. Flux-return gaps may be provided between the sample measurement volume defined by the coil and RF shields adjacent to the sample measurement volume, to confine the RF magnetic field to the sample measurement volume. Exemplary coils described herein are particularly suited for very high-frequency MRI measurements.