Various embodiments of the present invention relate to an electronic device and a method for controlling transmission power, the electronic device comprising: an amplification circuit; an antenna electrically connected to the amplification circuit; a variable element capable of adjusting the impedance between the amplification circuit and the antenna; and a control circuit, wherein the control circuit can be configured to: output a signal, having been amplified by a designated gain by means of the amplification circuit, to an external electronic device by using the antenna, in a state in which the variable element is adjusted to a first impedance; detect the approach of an external object during outputting of the signal; in response to the detection of the approach of the external object, check control information by which the first impedance of the variable element can be changed to a second impedance; and adjust the designated gain on the basis of at least the control information.

A cascading microwave directional amplifier (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set, such that the first Josephson device amplifies a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and propagate without amplification a signal of an n.sup.th frequency, and the n.sup.th Josephson device to amplify the signal of the n.sup.th frequency and propagate without amplification the signal of the first frequency from the multiplexed signal in the first signal flow direction through the series.

A cascading microwave directional amplifier (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set, such that the first Josephson device amplifies a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and propagate without amplification a signal of an n.sup.th frequency, and the n.sup.th Josephson device to amplify the signal of the n.sup.th frequency and propagate without amplification the signal of the first frequency from the multiplexed signal in the first signal flow direction through the series.

A cascading selective microwave directional amplifier (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies. Different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set. The series coupling causes the first Josephson device to amplify a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) in a first signal flow direction through the series coupling and the n.sup.th Josephson device to amplify a signal of an n.sup.th frequency in a second signal flow direction through the series, where the second signal flow direction is opposite of the first signal flow direction.

A cascading selective microwave directional amplifier (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies. Different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set. The series coupling causes the first Josephson device to amplify a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) in a first signal flow direction through the series coupling and the n.sup.th Josephson device to amplify a signal of an n.sup.th frequency in a second signal flow direction through the series, where the second signal flow direction is opposite of the first signal flow direction.

An on-chip Josephson parametric converter is provided. The on-chip Josephson parametric converter includes a Josephson ring modulator. The on-chip Josephson parametric converter further includes a lossless power divider, coupled to the Josephson ring modulator, having a single input port and two output ports for receiving a pump drive signal via the single input port, splitting the pump drive signal symmetrically into two signals that are equal in amplitude and phase, and outputting each of the two signals from a respective one of the two output ports. The pump drive signal excites a common mode of the on-chip Josephson parametric converter.

An on-chip Josephson parametric converter is provided. The on-chip Josephson parametric converter includes a Josephson ring modulator. The on-chip Josephson parametric converter further includes a lossless power divider, coupled to the Josephson ring modulator, having a single input port and two output ports for receiving a pump drive signal via the single input port, splitting the pump drive signal symmetrically into two signals that are equal in amplitude and phase, and outputting each of the two signals from a respective one of the two output ports. The pump drive signal excites a common mode of the on-chip Josephson parametric converter.

A low-noise directional amplifier includes a first port, a second port, a first coupler and a second coupler. The first port is coupled to a first coupler. The low-noise directional amplifier also includes at least two phase preserving amplifiers, a first phase preserving amplifier connected to the first coupler and a second coupler, and the second phase preserving amplifier connected to the first coupler and the second coupler.

A low-noise directional amplifier includes a first port, a second port, a first coupler and a second coupler. The first port is coupled to a first coupler. The low-noise directional amplifier also includes at least two phase preserving amplifiers, a first phase preserving amplifier connected to the first coupler and a second coupler, and the second phase preserving amplifier connected to the first coupler and the second coupler.

A cascading microwave directional amplifier (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set, such that the first Josephson device amplifies a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and propagate without amplification a signal of an n.sup.th frequency, and the n.sup.th Josephson device to amplify the signal of the n.sup.th frequency and propagate without amplification the signal of the first frequency from the multiplexed signal in the first signal flow direction through the series.