# US 9,520,909 B2 · Transmit noise reducer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,909 B2 - Document ID: US9520909B2 - Status: Granted - Kind: B2 - Application number: 14/560,842 - Filed: 2014-12-04 - Published: 2016-06-09 - Granted: 2016-12-13 - Earliest claimed: 2014-12-04 - Assignees: Raytheon Company - Applicants: Raytheon Company - Inventors: Tina P. Srivastava; Matthew A. Morton; John Cangeme - Web page: https://patentgrep.com/patent/US9520909B2 ## CPC - H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)} - H03H 2/001: {comprising magnetostatic wave network elements} - H04B: TRANSMISSION - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract A transmit drive circuit with high signal to noise and frequency agility. In one embodiment, a transmit circuit includes a digital to analog converter, an amplifier, and a signal to noise enhancer, the signal to noise enhancer being a nonlinear passive device that attenuates low-power signals while transmitting high power signals with little loss. The signal to noise enhancer may be fabricated as a thin film of yttrium iron garnet (YIG) epitaxially grown on a gadolinium gallium garnet (GGG) substrate, the GGG substrate secured to a microwave transmission line from the input to the output of the signal to noise enhancer, such that the thin film of yttrium iron garnet is close to the transmission line. ## Claims ### Claim 1 A transmit system, comprising: a digital-to-analog converter (DAC) having a digital input and an analog output; a first amplifier, having an input and an output, the input of the first amplifier being connected to the analog output of the DAC; a first signal-to-noise enhancer (SNE) having an input and an output, the input of the first SNE being connected to the output of the first amplifier, a second amplifier, having an input and an output, the input of the second amplifier being connected to the first SNE; and a second SNE having an input and an output, the input of the second SNE being connected to the output of the second amplifier, wherein each of the first SNE and second SNE comprising: a microwave transmission line connected between the input and the output of the first SNE; a magnetic component capable of supporting magneto static waves, the magnetic component secured in proximity to the microwave transmission line; one or more magnets secured in proximity to the magnetic component; the first SNE having the characteristic of allowing a signal to propagate from the input of the first SNE to the output of the first SNE: with a first attenuation when the power of the signal at the input of the SNE is less than a first threshold, and with a second attenuation when the power of the signal at the input of the SNE is greater than a second threshold, the first attenuation exceeding the second attenuation by at least 5 decibels (dB). ### Claim 2 (depends on 1) The transmit system of claim 1, wherein the output of the second SNE is connected to a transmitting antenna. ### Claim 3 (depends on 1) The transmit system of claim 1, wherein the magnetic component comprises a thin film of yttrium iron garnet (YIG) on a gadolinium gallium garnet (GGG) substrate. ### Claim 4 (depends on 3) The transmit system of claim 3, wherein the thin film of YIG is a single crystal of YIG, the GGG substrate is a single crystal of GGG, and the thin film of YIG is lattice-matched to the GGG substrate. ### Claim 5 (depends on 1) The transmit system of claim 1, wherein a portion of the transmission line in proximity with the magnetic component follows a substantially straight path. ### Claim 6 (depends on 5) The transmit system of claim 5, wherein the one or more magnets comprise two magnets, positioned and oriented with respect to the portion of the microwave transmission line so as to produce, in the magnetic component, a biasing magnetic field substantially parallel to the portion of the microwave transmission line. ### Claim 7 (depends on 1) The transmit system of claim 1, further comprising a plurality of additional components connected in cascade to form a chain having an input and an output, the output of the second SNE connected to the input of the chain, the plurality of additional components comprising one or more additional SNEs and one or more additional amplifiers, the additional SNEs and the additional amplifiers alternating in the chain, each additional SNE of the one or more additional SNEs having an input and an output, each additional SNE of the one or more additional SNEs comprising: a microwave transmission line connected between the input and the output of the additional SNE; a magnetic component capable of supporting magnetostatic waves; the magnetic component secured in proximity to the microwave transmission line; one or more magnets secured in proximity to the magnetic component; each additional SNE of the one or more additional SNEs having the characteristic of allowing a signal to propagate from the input of the additional SNE to the output of the additional SNE: with a first attenuation when the power of the signal at the input of the SNE is less than a first threshold, and with a second attenuation when the power of the signal at the input of the SNE is greater than a second threshold, the first attenuation exceeding the second attenuation by at least 5 decibels (dB). ### Claim 8 (depends on 7) The transmit system of claim 7, wherein the chain comprises, as a final element, an amplifier of the one or more additional amplifiers. ### Claim 9 (depends on 7) The transmit system of claim 7, wherein the chain comprises, as a final element, an SNE of the one or more additional SNEs. ### Claim 10 (depends on 9) The transmit system of claim 9, wherein the output of the chain is connected to a transmitting antenna. ### Claim 11 A transmit system, comprising: a first amplifier, having an input and an output; a plurality of signal-to-noise enhancers (SNEs) having an input and an output, each signal-to-noise enhancer (SNE) of the plurality of SNEs comprising: a microwave transmission line connected between the input and the output of the first SNE; a magnetic component capable of supporting magnetostatic waves, the magnetic component secured in proximity to the microwave transmission line; one or more magnets secured in proximity to the magnetic component; the first SNE having the characteristic of allowing a signal to propagate from the input of the first SNE to the output of the first SNE: with a first attenuation when the power of the signal at the input of the SNE is less than a first threshold, and with a second attenuation when the power of the signal at the input of the SNE is greater than a second threshold, the first attenuation exceeding the second attenuation by at least 5 decibels (dB); and the plurality of SNEs comprising a first SNE and a plurality of additional SNEs, the input of the first SNE being connected to the output of the first amplifier; a plurality of additional components comprising: one or more splitters; and a plurality of additional amplifiers, the plurality of additional components and the plurality of additional SNEs being connected in a tree structure having an input and a plurality of outputs, the output of the first SNE connected to the input of the tree structure. ### Claim 12 (depends on 11) The transmit system of claim 11, wherein each output of the plurality of outputs of the tree structure is connected to a transmitting antenna. ### Claim 13 (depends on 11) The transmit system of claim 11, wherein: the one or more splitters comprise a first splitter comprising an input and a plurality of outputs; the output of the first SNE is connected to the input of the first splitter; each of the outputs of the first splitter is connected to one of a plurality of first cascades, each of the first cascades being a cascade of an amplifier of the additional amplifiers and an SNE of the additional SNEs, each of the first cascades comprising an input and an output, the input of each first cascade being connected to the input of the amplifier of the first cascade, the output of the amplifier of each first cascade being connected to the input of the SNE of the first cascade, and the output of the SNE of each first cascade being connected to the output of the first cascade. ### Claim 14 (depends on 13) The transmit system of claim 13, wherein the output of each cascade of the plurality of first cascades is connected to a transmitting antenna. ### Claim 15 (depends on 13) The transmit system of claim 13, wherein: the one or more splitters further comprise a plurality of second splitters, each comprising an input and a plurality of outputs; the input of each of the plurality of second splitters being connected to the output of a respective first cascade, each output of each of the plurality of second splitters being connected to one of a plurality of second cascades, each of the second cascades being a cascade of an amplifier of the additional amplifiers and an SNE of the additional SNEs, each of the second cascades comprising an input and an output, the input of each second cascade being connected to the input of the amplifier of the second cascade, the output of the amplifier of each second cascade being connected to the input of the SNE of the second cascade, and the output of the SNE of each second cascade being connected to the output of the second cascade. ### Claim 16 (depends on 15) The transmit system of claim 15, wherein the output of each cascade of the plurality of second cascades is connected to a transmitting antenna. ### Claim 17 (depends on 11) The transmit system of claim 11, further comprising a digital-to-analog converter (DAC) having a digital input and an analog output, the output of the DAC being connected to the input of the first amplifier.