Patents by Inventor Donhee Ham

Donhee Ham has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20090168162
    Abstract: Microscopy methods and apparatus for manipulation, detection, imaging, characterization, sorting and/or assembly of biological or other materials, involving an integration of CMOS or other semiconductor-based technology and microfluidics in connection with a microscope. In one implementation, a microscope including optics and a stage is outfitted with various components relating to the generation of electric and/or magnetic fields, which are implemented on an IC chip. A microfluidic system is fabricated either directly on top of the IC chip, or as a separate entity that is then appropriately bonded to the IC chip, to facilitate the introduction and removal of cells in a biocompatible environment, or other particles/objects of interest suspended in a fluid. The patterned electric and/or magnetic fields generated by the IC chip can trap and move biological cells or other objects inside the microfluidic system to facilitate viewing via the microscope.
    Type: Application
    Filed: January 12, 2007
    Publication date: July 2, 2009
    Applicant: President and Fellows of Harvard College
    Inventors: Donhee Ham, Robert Westervelt, Thomas Hunt, Yong Liu, Hakho Lee
  • Patent number: 7339440
    Abstract: Methods and apparatus for implementing stable self-starting and self-sustaining electrical nonlinear pulse (e.g., soliton, cnoidal wave, or quasi-soliton) oscillators. In one example, a nonlinear pulse oscillator is implemented as a closed loop structure that comprises a nonlinear transmission line, an improved high-pass filter, and a nonlinear amplifier configured to provide a self-adjusting gain as a function of an average voltage of the oscillator signal, to provide a pulse waveform having a desired target amplitude. In one implementation, the nonlinear amplifier and high pass filter functions are integrated in a two stage nonlinear amplifier/filter apparatus employing complimentary NMOS and PMOS amplification components and associated filtering and feedback circuitry configured to essentially implement an electric circuit analog of a saturable absorber via an adaptive bias control technique.
    Type: Grant
    Filed: September 8, 2005
    Date of Patent: March 4, 2008
    Assignee: President and Fellows of Harvard College
    Inventors: David Ricketts, Xiaofeng Li, Donhee Ham
  • Patent number: 7274262
    Abstract: A standing wave oscillator to generate at least one voltage standing wave, comprising a closed-loop coplanar stripline including two conductors, and at least one amplifier disposed between the two conductors at a first location. The two conductors are connected together at a second location different from the first location to provide a zero voltage node for the at least one voltage standing wave. One or more of a tailored distributed amplification scheme, a plurality of linear conductive strips disposed in proximity to the coplanar stripline, and a tapered coplanar stripline configuration may be used with the closed loop structure. A particular amplifier configuration involving cross-coupling of the coplanar stripline conductors may be employed to facilitate single mode operation, using a particular resonator topology so as to avoid inducing significant loss in the oscillator.
    Type: Grant
    Filed: July 27, 2006
    Date of Patent: September 25, 2007
    Assignee: Presidents and Fellows of Harvard College
    Inventors: Donhee Ham, William Franklin Andress, Yong Liu
  • Patent number: 7242272
    Abstract: Methods and apparatus involving semiconductor devices based on coplanar striplines (CPS). In one example, high-speed microelectronic devices based on coplanar stripline implementations support differential signals in a range of approximately from 1 Gigahertz to at least 60 Gigahertz. In one aspect, CPS-based devices incorporate various features that dramatically increase the quality factor Q of the resulting device. In another aspect, an enhancement of the quality factor Q is achieved while at the same time reducing the phase velocity of one or more waves propagating in the device, thereby also facilitating the fabrication of relatively smaller devices. In yet another aspect, a tapered coplanar stripline configuration results in position-dependent line parameters, which may be exploited to achieve significantly high-Q devices.
    Type: Grant
    Filed: July 19, 2004
    Date of Patent: July 10, 2007
    Assignee: President and Fellows of Harvard College
    Inventors: Donhee Ham, William Franklin Andress, Yong Liu
  • Publication number: 20060261905
    Abstract: A standing wave oscillator to generate at least one voltage standing wave, comprising a closed-loop coplanar stripline including two conductors, and at least one amplifier disposed between the two conductors at a first location. The two conductors are connected together at a second location different from the first location to provide a zero voltage node for the at least one voltage standing wave. One or more of a tailored distributed amplification scheme, a plurality of linear conductive strips disposed in proximity to the coplanar stripline, and a tapered coplanar stripline configuration may be used with the closed loop structure. A particular amplifier configuration involving cross-coupling of the coplanar stripline conductors may be employed to facilitate single mode operation, using a particular resonator topology so as to avoid inducing significant loss in the oscillator.
    Type: Application
    Filed: July 27, 2006
    Publication date: November 23, 2006
    Applicant: President and Fellows of Harvard College
    Inventors: Donhee Ham, William Andress, Yong Liu
  • Patent number: 7091802
    Abstract: Methods and apparatus for implementing standing wave oscillators (SWOS) using coplanar striplines (CPS). One example is given by a quarter-wavelength (?/4) coplanar stripline standing wave oscillator (SWO), while another implementation utilizes a closed-loop coplanar stripline configuration. In various aspects, SWOs are configured to optimize sinusoidal performance at high frequencies with low power dissipation by incorporating various features that dramatically increase the quality factor Q of the oscillator. In particular, in one aspect, an amplitude-dependent tailored distributed amplification scheme is employed as a mode control technique using multiple amplifiers having different gains along the length of the coplanar stripline. In another aspect, a coplanar stripline configured such that its resistance per unit length R and conductance per unit length G are discreet or continuous functions of position along the coplanar stripline is employed to reduce SWO losses.
    Type: Grant
    Filed: July 19, 2004
    Date of Patent: August 15, 2006
    Assignee: President and Fellows of Harvard College
    Inventors: Donhee Ham, William Franklin Andress, Yong Liu
  • Publication number: 20060114550
    Abstract: Methods and apparatus for implementing stable self-starting and self-sustaining electrical nonlinear pulse (e.g., soliton, cnoidal wave, or quasi-soliton) oscillators. In one example, a nonlinear pulse oscillator is implemented as a closed loop structure that comprises a nonlinear transmission line, an improved high-pass filter, and a nonlinear amplifier configured to provide a self-adjusting gain as a function of an average voltage of the oscillator signal, to provide a pulse waveform having a desired target amplitude. In one implementation, the nonlinear amplifier and high pass filter functions are integrated in a two stage nonlinear amplifier/filter apparatus employing complimentary NMOS and PMOS amplification components and associated filtering and feedback circuitry configured to essentially implement an electric circuit analog of a saturable absorber via an adaptive bias control technique.
    Type: Application
    Filed: September 8, 2005
    Publication date: June 1, 2006
    Inventors: David Ricketts, Xiaofeng Li, Donhee Ham
  • Publication number: 20060020371
    Abstract: Methods and apparatus for manipulation, detection, imaging, characterization, sorting and/or assembly of biological or other materials, involving an integration of CMOS or other semiconductor-based technology and microfluidics. In one implementation, various components relating to the generation of electric and/or magnetic fields are implemented on an IC chip that is fabricated using standard protocols. The generated electric and/or magnetic fields are used to manipulate and/or detect one or more dielectric and/or magnetic particles and distinguish different types of particles. A microfluidic system is fabricated either directly on top of the IC chip, or as a separate entity that is then appropriately bonded to the IC chip, to facilitate the introduction and removal of cells in a biocompatible environment, or other particles/objects of interest suspended in a fluid.
    Type: Application
    Filed: April 13, 2005
    Publication date: January 26, 2006
    Applicant: President and Fellows of Harvard College
    Inventors: Donhee Ham, Robert Westervelt, Thomas Hunt, Yong Liu, Hakho Lee
  • Publication number: 20050068127
    Abstract: Methods and apparatus involving semiconductor devices based on coplanar striplines (CPS). In one example, high-speed microelectronic devices based on coplanar stripline implementations support differential signals in a range of approximately from 1 Gigahertz to at least 60 Gigahertz. In one aspect, CPS-based devices incorporate various features that dramatically increase the quality factor Q of the resulting device. In another aspect, an enhancement of the quality factor Q is achieved while at the same time reducing the phase velocity of one or more waves propagating in the device, thereby also facilitating the fabrication of relatively smaller devices. In yet another aspect, a tapered coplanar stripline configuration results in position-dependent line parameters, which may be exploited to achieve significantly high-Q devices.
    Type: Application
    Filed: July 19, 2004
    Publication date: March 31, 2005
    Applicant: President and Fellows of Harvard College
    Inventors: Donhee Ham, William Andress, Yong Liu
  • Publication number: 20050068116
    Abstract: Methods and apparatus for implementing standing wave oscillators (SWOS) using coplanar striplines (CPS). One example is given by a quarter-wavelength (?/4) coplanar stripline standing wave oscillator (SWO), while another implementation utilizes a closed-loop coplanar stripline configuration. In various aspects, SWOs are configured to optimize sinusoidal performance at high frequencies with low power dissipation by incorporating various features that dramatically increase the quality factor Q of the oscillator. In particular, in one aspect, an amplitude-dependent tailored distributed amplification scheme is employed as a mode control technique using multiple amplifiers having different gains along the length of the coplanar stripline. In another aspect, a coplanar stripline configured such that its resistance per unit length R and conductance per unit length G are discreet or continuous functions of position along the coplanar stripline is employed to reduce SWO losses.
    Type: Application
    Filed: July 19, 2004
    Publication date: March 31, 2005
    Applicant: President and Fellows of Harvard College
    Inventors: Donhee Ham, William Andress, Yong Liu