Patents by Inventor Xiang Guan

Xiang Guan 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: 20100231452
    Abstract: A phased array mm-wave device includes a substrate, a mm-wave transmitter integrated onto the substrate configured to transmit a mm-wave signal and/or a mm-wave receiver integrated onto the substrate and configured to receive a mm-wave signal. The mm-wave device also includes a phased array antenna system integrated onto the substrate and including two or more antenna elements. The phased array mm-wave device also includes one or more dielectric lenses. A distributed mm-wave distributed combining tree circuit includes at least two pairs of differential transconductors with regenerative degeneration and accepts at least two differential input signals. Two mm-wave loopback methods measure the phased array antenna patterns and the performance of an integrated receiver transmitter system.
    Type: Application
    Filed: September 22, 2006
    Publication date: September 16, 2010
    Applicant: California Institute of Technology
    Inventors: Aydin Babakhani, Xiang Guan, Seyed Ali Hajimiri, Abbas Komijani, Arun Natarajan
  • Patent number: 7502631
    Abstract: A phased-array receiver is adapted so as to be fully integrated and fabricated on a single silicon substrate. The phased-array receiver is operative to receive a 24 GHz signal and may be adapted to include 8-elements formed in a SiGe BiCMOS technology. The phased-array receiver utilizes a heterodyne topology, and the signal combining is performed at an IF of 4.8 GHz. The phase-shifting with 4 bits of resolution is realized at the LO port of the first down-conversion mixer. A ring LC VCO generates 16 different phases of the LO. An integrated 19.2 GHz frequency synthesizer locks the VCO frequency to a 75 MHz external reference. Each signal path achieves a gain of 43 dB, a noise figure of 7.4 dB, and an IIP3 of ?11 dBm. The 8-path array achieves an array gain of 61 dB, a peak-to-null ratio of 20 dB, and improves the signal-to-noise ratio at the output by 9 dB.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: March 10, 2009
    Assignee: California Institute of Technology
    Inventors: Hossein Hashemi, Xiang Guan, Seyed Ali Hajimiri
  • Patent number: 7489194
    Abstract: A radio-frequency amplifier is provided. The radio-frequency amplifier includes a transistor having an input terminal, an output terminal, a control terminal, and a transconductance gm. A series-connected feed-through resistance Rf and feed-through capacitance Cf is connected in parallel with the input terminal and the output terminal of the transistor. A load resistance RL is connected to the output terminal. The control terminal of the transistor is biased at a fixed voltage. Part of the transistor noise follows the looped path through the feed-through resistor instead of passing on to the load, which reduces the noise figure of the amplifier. The value of gm, Rf and RL are chosen in a way to keep the input impedance of the amplifier matched to a well-defined signal source impedance.
    Type: Grant
    Filed: December 5, 2006
    Date of Patent: February 10, 2009
    Assignee: California Institute of Technology
    Inventors: Seyed-Ali Hajimiri, Xiang Guan
  • Publication number: 20080113643
    Abstract: A circuit features a balun having an unbalanced input and a balanced output, and a differential coupler having a symmetrical structure about a center axis. The differential coupler has a differential input and a differential output, the differential input being coupled to the balanced output of the balun. An impedance element is coupled to a circuit node of the differential coupler at a point along the center axis. Other embodiments are also described and claimed.
    Type: Application
    Filed: November 9, 2007
    Publication date: May 15, 2008
    Inventors: Xiang Guan, Chinh Huy Doan, Sohrab Emami-Neyestanak
  • Publication number: 20070075779
    Abstract: A radio-frequency amplifier is provided. The radio-frequency amplifier includes a transistor having an input terminal, an output terminal, a control terminal, and a transconductance gm. A series-connected feed-through resistance Rf and feed-through capacitance Cf is connected in parallel with the input terminal and the output terminal of the transistor. A load resistance RL is connected to the output terminal. The control terminal of the transistor is biased at a fixed voltage. Part of the transistor noise follows the looped path through the feed-through resistor instead of passing on to the load, which reduces the noise figure of the amplifier. The value of gm, Rf and RL are chosen in a way to keep the input impedance of the amplifier matched to a well-defined signal source impedance.
    Type: Application
    Filed: December 5, 2006
    Publication date: April 5, 2007
    Inventors: Seyed-Ali Hajimiri, Xiang Guan
  • Patent number: 7157972
    Abstract: A radio-frequency amplifier is provided. The radio-frequency amplifier includes a transistor having an input terminal, an output terminal, a control terminal, and a transconductance gm. A series-connected feed-through resistance Rf and feed-through capacitance Cf is connected in parallel with the input terminal and the output terminal of the transistor. A load resistance RL is connected to the output terminal. The control terminal of the transistor is biased at a fixed voltage. Part of the transistor noise follows the looped path through the feed-through resistor instead of passing on to the load, which reduces the noise figure of the amplifier. The value of gm, Rf and RL are chosen in a way to keep the input impedance of the amplifier matched to a well-defined signal source impedance.
    Type: Grant
    Filed: December 9, 2003
    Date of Patent: January 2, 2007
    Assignee: California Institute of Technology
    Inventors: Seyed-Ali Hajimiri, Xiang Guan
  • Publication number: 20050227660
    Abstract: A phased-array receiver is adapted so as to be fully integrated and fabricated on a single silicon substrate. The phased-array receiver is operative to receive a 24 GHz signal and may be adapted to include 8-elements formed in a SiGe BiCMOS technology. The phased-array receiver utilizes a heterodyne topology, and the signal combining is performed at an IF of 4.8 GHz. The phase-shifting with 4 bits of resolution is realized at the LO port of the first down-conversion mixer. A ring LC VCO generates 16 different phases of the LO. An integrated 19.2 GHz frequency synthesizer locks the VCO frequency to a 75 MHz external reference. Each signal path achieves a gain of 43 dB, a noise figure of 7.4 dB, and an IIP3 of ?11 dBm. The 8-path array achieves an array gain of 61 dB, a peak-to-null ratio of 20 dB, and improves the signal-to-noise ratio at the output by 9 dB.
    Type: Application
    Filed: November 12, 2004
    Publication date: October 13, 2005
    Applicant: California Institute of Technology
    Inventors: Hossein Hashemi, Xiang Guan, Seyed Hajimiri
  • Publication number: 20040124922
    Abstract: A radio-frequency amplifier is provided. The radio-frequency amplifier includes a transistor having an input terminal, an output terminal, a control terminal, and a transconductance gm. A series-connected feed-through resistance Rf and feed-through capacitance Cf is connected in parallel with the input terminal and the output terminal of the transistor. A load resistance RL is connected to the output terminal. The control terminal of the transistor is biased at a fixed voltage. Part of the transistor noise follows the looped path through the feed-through resistor instead of passing on to the load, which reduces the noise figure of the amplifier. The value of gm, Rf and RL are chosen in a way to keep the input impedance of the amplifier matched to a well-defined signal source impedance.
    Type: Application
    Filed: December 9, 2003
    Publication date: July 1, 2004
    Inventors: Seyed-Ali Hajimiri, Xiang Guan