Abstract: A DC block structure includes a dielectric (1), transmission lines (2a, 2b) having characteristic impedance of 50? and formed on a surface of the dielectric (1), transmission lines (3a, 3b) formed on the surface of the dielectric (1) so as to be connected with the transmission lines (2a, 2b) and designed so that characteristic impedance is higher than the characteristic impedance of the transmission lines (2a, 2b), and a capacitor (4) mounted on the transmission lines (3a, 3b) so as to connect the transmission line (3a) and the transmission line (3b) in series.

Abstract: An embodiment is a distributed amplifier including amplifier blocks, each of the amplifier blocks including a first transmission line to receive input of a signal to an input end, a second transmission line to output a signal from an output end, a first termination resistor having a first end connected to a terminal end of the first transmission line, a second termination resistor having a first end connected to an input end of the second transmission line, and unit cells arranged along the first and second transmission lines, each of the unit cells having an input terminal connected to the first transmission line and an output terminal connected to the second transmission line, the amplifier blocks are connected in cascade such that a terminal end of the second transmission line of one of the amplifier blocks is connected to the first transmission line of a subsequent amplifier block.

Abstract: In some embodiments, the phase adjustment circuit includes a clock generator that is configured to generate a sinusoidal clock signal, and may include a variable amplifier that is configured to receive the clock signal output from the clock generator as an input, output an amplitude-adjusted sinusoidal differential clock signal, and output an amplitude-adjusted in-phase signal. The phase adjustment circuit may include an adder that is configured to output a differential signal obtained by adding the in-phase signal to each of a positive phase side and a negative phase side of the differential clock signal output from the variable amplifier, a differential transmission line that includes two transmission lines configured to transmit the differential signal output from the adder, and a terminal circuit that is configured to terminate the differential transmission line where a signal is output from a terminal of any one of the two transmission lines.

Abstract: An embodiment is a phase adjustment circuit includes a sine wave output circuit, a first multiplier, a second multiplier, and an adder. The sine wave output circuit is configured to output two sine wave signals of a fixed phase difference. The first multiplier is configured to multiply an amplitude of a first sine wave signal output from the sine wave output circuit by a first variable to generate a first output signal. The second multiplier is configured to multiply an amplitude of a second sine wave signal output from the sine wave output circuit by a second variable to generate a second output signal. The adder is configured to add the first output signal from the first multiplier and the second output signal from the second multiplier.

Abstract: A mixer includes a transistor to which an IF signal of ae positive phase side is input, a transistor to which an IF signal of a negative phase side is input, a transistor to which an LO signal is input, and a synthesizer which synthesizes components of a RF frequency band output from the drain terminals of the transistors in a negative phase, and synthesizes components of an IF frequency band output from the drain terminals of the transistors in the same phase.

Abstract: A multiplexer includes an impedance converter. The impedance converter includes: a transmission line having a length of ?/4 (? is an in-transmission-line wavelength of a signal) and a characteristic impedance of 35?; and a transmission line having a length of ?/4 and a characteristic impedance of 70?. The impedance converter includes: a transmission line having a length of ?/4 and a characteristic impedance of 35?; and a transmission line having a length of ?/4 and a characteristic impedance of 70?.

Abstract: An embodiment includes an output circuit with transistors and a withstand voltage protection circuit. The withstand voltage protection circuit includes resistors connected between an output signal terminal on the positive phase side and an output signal terminal on the negative phase side. A switch includes an NMOS transistor having a gate terminal connected to the connection point of the resistors, a drain terminal connected to the bias voltage, and a source terminal connected to the base terminal of the transistor.

Abstract: In some implementations, the device may include a clock generator configured to generate a sinusoidal clock signal. The device may include a delay circuit configured to delay a signal output from the clock generator. The device may also include a first multiplier configured to output a signal obtained by multiplying an amplitude of the signal output from the clock generator by a first constant. Additionally, the device may include a second multiplier configured to output a signal obtained by multiplying an amplitude of the signal output from the delay circuit by a second constant. Also, the device may include an adder configured to add the signal output from the first multiplier and the signal output from the second multiplier.

Abstract: The mixer circuit includes a mixer, an LO matching circuit inserted between an LO signal terminal and a first terminal of the mixer, an IF matching circuit inserted between the IF signal terminal and a second terminal of the mixer, and an RF matching circuit inserted between an RF signal terminal and a third terminal of the mixer. In the RF matching circuit, a reflection characteristic is set such that a minimum value of reflection loss appears on a high-frequency side of the frequency of the LO signal.

Abstract: The driver circuit includes DC cut capacitors, an input buffer, input termination resistors connected in series between differential input signal terminals and an ESD protection circuit connected to a connection point of the input terminal resistors. The ESD protection circuit includes diodes.

Abstract: A phase adjustment circuit includes a clock generation unit (1) which generates a sinusoidal differential clock signal; a variable amplifier (2) which receives a differential clock signal output from the clock generation unit (1) as an input, outputs an amplitude-adjusted differential clock signal, and simultaneously outputs an amplitude-adjusted in-phase signal; an adding unit (3) which adds an in-phase signal to each of a positive phase side and a negative phase side of the differential clock signal output from the variable amplifier (2); a differential transmission line (4) which transmits the differential signal output from the adding unit (3); and a terminal circuit (5) which terminates the differential transmission line (4).

Abstract: Each unit cell (4a-1 to 4a-N) of the distributed double balanced mixer outputs a signal (R++) obtained by multiplexing the LO signal (LO+) on the positive phase side and the IF signal (IF+) on the positive phase side, a signal (RF??) obtained by multiplexing the LO signal (LO?) on the negative phase side and the IF signal (IF?) on the negative phase side, a signal (RF?+) obtained by multiplexing the LO signal (LO?) on the negative phase side and the IF signal (IF+) on the positive phase side, and a signal (RF+?) obtained by multiplexing LO signal (LO+) on the positive phase side and IF signal (IF?) on the negative phase side, to transmission lines (CPW20pp, CPW20nn, CPW20np, CPW20pn), without synthesizing the signals.

Abstract: A distributed amplifier includes: a transmission line having an input end that an input signal is input to; a transmission line having an output end that an output signal is output from; an input termination resistor connected to an end terminal of the transmission line; a plurality of unit cells arranged along the transmission lines, and having input terminals connected to the transmission line and output terminals connected to the transmission line; and a variable current source having one end connected to the end terminal of the transmission line and another end connected to a power supply voltage, and capable of adjusting a current amount between the transmission line and the power supply voltage.

Abstract: A voltage setting circuit includes a frequency comparator that compares the oscillation frequencies of a first distributed voltage-controlled oscillator and a second distributed voltage-controlled oscillator and a frequency determination circuit that determines the levels of the oscillation frequencies of the first distributed voltage-controlled oscillator and the second distributed voltage-controlled oscillator. The bias to be supplied to the first distributed voltage-controlled oscillator and the bias to be supplied to the second distributed voltage-controlled oscillator are determined in accordance with a result of the determination. The bias at a time when the levels of the oscillation frequencies are reversed is determined to be the optimum bias, and the optimum bias is supplied to the core circuit.

Abstract: An amplifier circuit comprises a variable degeneration circuit connected to emitter terminals of transistors, and a variable negative capacitance circuit connected to differential output signal terminals. The variable degeneration circuit includes a variable capacitor and a resistor. The variable negative capacitance circuit, which is a variable current source, includes a transistor, a capacitor, and a variable current source. The variable negative capacitance circuit includes transistors, a capacitor, and variable current sources.

Abstract: A driver circuit includes a differential pair of transistors that amplify differential input signals and output the amplified differential input signals from signal output terminals, a current source that supplies a constant current to the differential pair of transistors, a switch that stops the current supply from the current source to the differential pair of transistors during a shutdown mode period, capacitors each having one end connected to the ground, a switch that connects the capacitor to the signal output terminal during the shutdown mode period and disconnects the capacitor from the signal output terminal during an amplification mode period, and a switch that connects the capacitor to the signal output terminal during the shutdown mode period and disconnects the capacitor from the signal output terminal during the amplification mode period.

Abstract: An embodiment is a mixer circuit including a power divider that divides an LO signal with equal amplitude and equal phase, delay circuits, unit mixers, transmission lines, and a power combiner that combines, with equal amplitude and equal phase, RF signals output from the unit mixers. A phase delay amount of the LO signal by the k-th delay circuit from an IF port side is set to ?1?k??IF or ?1+k??IF, where ??IF is a phase delay amount with respect to an IF signal of each of the transmission lines.

Abstract: A distributed circuit includes: a first transmission line that has an input end to which an input signal is input; a second transmission line that has an output end from which an output signal is output; a plurality of unit cells that are disposed along the first and second transmission lines, the input terminals of the unit cells being connected to the first transmission line, the output terminals of the unit cells being connected to the second transmission line; two input termination resistors connected in parallel to an end of the first transmission line; and two output termination resistors connected in parallel to an end of the second transmission line. In the distributed circuit, at least one input termination resistor is a temperature-gradient resistor, and voltages at the two input termination resistors are changed symmetrically.

Abstract: A permittivity measuring method includes measuring a set of phases at sampling frequencies of at least three points in each of a first-half portion and a second-half portion of a phase characteristic of electromagnetic waves that passed through a measurement target, if the mode of the phase changes of both sets of phases belongs to a phase group in which change of the at least three points in the first half and change of at least three points in the second half are both monotonic change, maximal values, or minimal values, calculating the permittivity using the phase slope of the phases in the first-half portion and the phases in the second-half portion, and if the mode of the phase changes does not belong to the phase group, calculating the permittivity by fitting the phases of either the first half or the second half to a quadratic function.

Abstract: An embodiment is a multiplexer including a first distributed amplifier with an impedance matched to 50?, the first distributed amplifier configured to receive a first signal and output a first amplified signal, a second distributed amplifier with an impedance matched to 50?, the second distributed amplifier configured to receive a second signal and output a second amplified signal, and a passive multiplexer configured to multiplex the first amplified signal and the second amplified signal, and output a multiplexed signal to a signal output terminal, the passive multiplexer including a first resistor having a first end to receive the first amplified signal, a second resistor having a first end to receive the second amplified signal, and a third resistor having a first end connected to second ends of the first and second resistors and a second end connected to the signal output terminal.