According to some aspects, a quantum circuit is provided including a plurality of non-linear circuit elements coupled together in series and in parallel, such that at least two of the circuit elements are coupled together in series and at least two of the circuit elements are coupled together in parallel, wherein the quantum circuit is configured to act as an amplifier.

A method amplifies a signal on a transmission line. A driver transmits an initial signal on a transmission line, which is overlaid on an Alternating Impedance-Electromagnetic BandGap (AI-EBG) structure (i.e., a reference plane) on a circuit board. The AI-EBG structure induces an alternating change to an impedance in the transmission line. The alternating change to the impedance creates a reflection signal to an initial signal on the transmission line, and the reflection signal and the initial signal combine to create an amplified signal.

An electronic structure includes a conductor layer; an insulation layer adjacent to the conductor layer; an Alternating Impedance Electromagnetic Bandgap (AI-EBG) layer adjacent to the conductor layer; and a signal driver, a transmission line, and a destination device overlaid on the AI-EBG layer, such that the AI-EBG layer induces an alternating change to an impedance in the transmission line. The alternating change to the impedance creates a reflection signal to an initial signal on the transmission line, and the reflection signal and the initial signal combine to create an amplified signal.

An electronic structure includes a conductor layer; an insulation layer adjacent to the conductor layer; an Alternating Impedance Electromagnetic Bandgap (AI-EBG) layer adjacent to the conductor layer; and a signal driver, a transmission line, and a destination device overlaid on the AI-EBG layer, such that the AI-EBG layer induces an alternating change to an impedance in the transmission line. The alternating change to the impedance creates a reflection signal to an initial signal on the transmission line, and the reflection signal and the initial signal combine to create an amplified signal.

A method amplifies a signal on a transmission line. A driver transmits an initial signal on a transmission line, which is overlaid on an Alternating Impedance-Electromagnetic BandGap (AI-EBG) structure (i.e., a reference plane) on a circuit board. The AI-EBG structure induces an alternating change to an impedance in the transmission line. The alternating change to the impedance creates a reflection signal to an initial signal on the transmission line, and the reflection signal and the initial signal combine to create an amplified signal.

An electronic structure includes a conductor layer; an insulation layer adjacent to the conductor layer; an Alternating Impedance Electromagnetic Bandgap (AI-EBG) layer adjacent to the conductor layer; and a signal driver, a transmission line, and a destination device overlaid on the AI-EBG layer, such that the AI-EBG layer induces an alternating change to an impedance in the transmission line. The alternating change to the impedance creates a reflection signal to an initial signal on the transmission line, and the reflection signal and the initial signal combine to create an amplified signal.

An electronic structure includes a conductor layer; an insulation layer adjacent to the conductor layer; an Alternating Impedance Electromagnetic Bandgap (AI-EBG) layer adjacent to the conductor layer; and a signal driver, a transmission line, and a destination device overlaid on the AI-EBG layer, such that the AI-EBG layer induces an alternating change to an impedance in the transmission line. The alternating change to the impedance creates a reflection signal to an initial signal on the transmission line, and the reflection signal and the initial signal combine to create an amplified signal.

A nonlinear parametric device includes a planar substrate and a millimeter-wave resonator formed from superconductive material deposited on the planar substrate. When the resonator is cooled below a critical temperature, it exhibits nonlinear kinetic inductance that may be used to implement millimeter-wave nonlinear frequency generation and parametric amplification. Millimeter waves may be coupled into, and out of, the nonlinear parametric device with hollow rectangular electromagnetic waveguides. Niobium nitride is an excellent superconductive material for kinetic inductance due to its high intrinsic sheet inductance, a critical temperature that is higher than many other superconductive materials, and relatively low loss at millimeter-wave frequencies.

A nonlinear parametric device includes a planar substrate and a millimeter-wave resonator formed from superconductive material deposited on the planar substrate. When the resonator is cooled below a critical temperature, it exhibits nonlinear kinetic inductance that may be used to implement millimeter-wave nonlinear frequency generation and parametric amplification. Millimeter waves may be coupled into, and out of, the nonlinear parametric device with hollow rectangular electromagnetic waveguides. Niobium nitride is an excellent superconductive material for kinetic inductance due to its high intrinsic sheet inductance, a critical temperature that is higher than many other superconductive materials, and relatively low loss at millimeter-wave frequencies.

A device comprises a Josephson junction traveling-wave parametric circuit. The Josephson junction traveling-wave parametric circuit comprises unit cells which are coupled in series to form a transmission line between an input port and an output port. Each unit cell comprises a series Josephson junction, and a dispersive ground-shunt admittance configured to cause suppression of one or more sideband frequency components.