Patents by Inventor Stephen A. Maas

Stephen A. Maas 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).

  • Patent number: 6690247
    Abstract: A nonlinear transmission-line waveform generator for generating a comb of frequencies and relatively short duration pulses, for example, in the range of picoseconds and tens of picoseconds, that are adapted to being utilized with ultra wideband radios in order to improve the bandwidth of such radios by an order of magnitude, for example, up to tens and even hundreds of GHz. In particular, the nonlinear transmission line waveform generator in accordance with the present invention consists of a microstrip or coplanar waveguide line. In accordance with an important aspect of the invention, the &Dgr;C/&Dgr;V characteristic of the nonlinear transmission line is matched to the frequency and amplitude of the input sinusoidal waveform.
    Type: Grant
    Filed: February 5, 1999
    Date of Patent: February 10, 2004
    Assignee: Northrop Grumman Corporation
    Inventors: Mark Kintis, Daniel K. Ko, Flavia S. Fong, Stephen A. Maas
  • Patent number: 6320480
    Abstract: A programmable phase shifter (20, 40, 54, 60, 62) includes a variable delay line formed from a nonlinear transmission line (NLTL) (26, 28, 46, 28), which enables the device to be used in applications where the frequency of the input signal varies. A variable DC bias applied to the NLTL (26, 28, 46, 48) varies the NLTL's phase velocity and delay. Since the characteristic impedance of a transmission line changes as a function of the DC bias, the input voltage standing wave ratio (VSWR) also changes. In order to compensate for the change in the input VSWR, a pair of NLTLs (26, 28, 46, 48) are coupled at the input and output to a pair of hybrid couplers (22, 42). In an alternate embodiment of the invention, the hybrid couplers (22, 24) are replaced with 180° power splitters (42, 44) in order to reduce distortion of the device. In other embodiments of the invention (40, 54), a nonlinear transmission lines are used to form both discretely variable and continuously variable digital phase shifters (60, 62).
    Type: Grant
    Filed: October 26, 1999
    Date of Patent: November 20, 2001
    Assignee: TRW Inc.
    Inventors: Mark Kintis, Daniel K. Ko, Stephen A. Maas
  • Patent number: 5596325
    Abstract: An FM-CW radar transceiver comprising an oscillator connected to an input of a power divider having first and second terminal outputs. The first terminal output of the power divider is connected to an input of a first diode and a first shorted stub. The second terminal output of the power divider is connected to an input of a phase shifter with the output of the phase shifter connected to an input of a second diode and a second shorted stub. The outputs of the first and second diodes are each connected to inputs of first and second intermediate frequency (IF) filters and then through first and second IF blocking structures terminating at a common antenna port. An open stub is connected to the common antenna port with the outputs of the first and second IF filters each connected to an IF port or channel. In use, the FM-CW transceiver operates as a frequency multiplier for transmitting, and simultaneously as a subharmonically pumped "I/Q" mixer for reception.
    Type: Grant
    Filed: July 7, 1995
    Date of Patent: January 21, 1997
    Assignee: Nonlinear Technologies, Inc.
    Inventor: Stephen A. Maas
  • Patent number: 4949398
    Abstract: A simple balanced-mixer circuit that uses the resistive channel of a GaAs MESFET exhibits superior intermodulation performance, with other performance parameters, e.g., conversion loss, port impedances, and LO sensitivity, being equal to or better than other diode mixers.
    Type: Grant
    Filed: June 9, 1988
    Date of Patent: August 14, 1990
    Assignee: The Aerospace Corporation
    Inventor: Stephen A. Maas