Abstract: A variable circuit that has a device that changes the mechanical state thereof and has a characteristic that is changed by a change of the mechanical state of the device, the variable circuit including: a controlling section 20 that turns the device from a current state, which is a current mechanical state, to a different state, which is a state different from the current state, and returns the device from the different state to the current state; and a trigger transmitting section 22 that transmits a first trigger to turn said device from the current state to the different state to the controlling section 20.

Abstract: An irreversible circuit element is configured by including a magnetic substance, a plurality of central conductors L1 to L3, one ends of which are connected to different input/output ports, arranged on the magnetic substance so as to intersect each other while being insulated from each other, a first conductor P1 connected to the other ends of all the central conductors L1 to L3, a second conductor, a plurality of matching capacitors (each configured by C1 to C3) connecting the one end of the central conductors L1 to L3 and the second conductor and a variable matching mechanism V1, one end of which is connected or integrated with the second conductor, capable of changing reactance between the one end and the other end thereof.

Abstract: A signal input/output line 101 is used for input and output of a signal. A first resonating part 102 is connected to the signal input/output line 101 at one end and is opened at the other end. A second resonating part 103 is connected to a ground conductor 105 at one end and is opened at the other end. A connecting line 104 has a predetermined length and is connected to a point of connection between the signal input/output line 101 and the first resonating part 102 at one end and is connected to a predetermined point on the second resonating part 103 at the other end.

Abstract: A circulator extracts a transmission signal sent from a transmitter to antenna via the circulator and a duplexer, reflected by an antenna, and returned via the duplexer to the transmitter side. The amplitude and phase of the extracted signal are adjusted by an amplitude-and-phase adjuster to generate an offset signal having the same amplitude and the opposite phase with respect to a leaking transmission signal included in a signal output from a third terminal of the duplexer when combined by a combiner. The offset signal is combined in the combiner with the leaking transmission signal included in the signal output from the third terminal of the duplexer to suppress the leaking transmission signal.

Abstract: First, second and third matching parts 110, 120, and 130 are connected in series between a circuit element 199 whose impedance has a frequency characteristic and a circuitry 198 having a constant impedance. The second matching part 120 has the capability of converting impedances. The first matching part 110 operates as an element having reactance values according to any of frequency bands selected by exclusive switching between on and off of switches 118, 119 and the third matching part 130 operates as an element having reactance values according to any of the frequency bands selected by switching between on and off of a switch 133, thereby providing matching in each frequency band. A seventh reactance circuit 131 is configured on the basis of an interdependence relation with the configuration of a fifth reactance circuit 115 and an eighth reactance circuit 132.

Abstract: A radio communication device in which the output transmission signal of a high-frequency power amplifying part is sent out to an antenna via a circulator, a high-frequency signal reflected from the antenna is transferred via the circulator to a rectifying part to obtain a direct current power, and the direct current power is supplied to a power amplifying part or another constituent part in the radio communication device as an aid to the power supply from a power supply unit.

Abstract: A coplanar waveguide resonator (100a) has a center conductor (101) formed on a dielectric substrate (105) that has a line conductor (a center line conductor) (101b) extending in the input/output direction, a ground conductor (103) that is disposed on the dielectric substrate (105) across a gap section from the center conductor (101), and a line conductor (a base stub) (104) formed as an extension line from the ground conductor (103), and a part of the base stub (104) constitutes a line conductor (a first collateral line conductor) (104a) disposed in parallel with the center line conductor (101b).

Abstract: A variable resonator that comprises a loop line (902) to which two or more switches (903) are connected and N variable reactance means (102) (N?3), in which switches (903) are severally connected to different positions on the loop line (902), the other ends of the switches are severally connected to a ground conductor, and the switches are capable of switching electrical connection/non-connection between the ground conductor and the loop line (902), the variable reactance blocks (102) are severally settable to the same reactance value, and the variable reactance blocks (102) are electrically connected to the loop line (902) as branching circuits along the circumference direction of the loop line (902) at equal electrical length intervals.

Abstract: A variable resonator that comprises a loop line (902) to which two or more switches (903) are connected and N of reactance circuits (102) (N?3), in which switches (903) are severally connected to different positions on the loop line (902), the other ends of the switches are severally connected to a ground conductor, and the switches are capable of switching electrical connection/non-connection between the ground conductor and the loop line (902), the reactance circuits (102) severally have the same reactance value, the loop line (902) has a circumference corresponding to one wavelength or integral multiple thereof at a resonance frequency corresponding to each reactance value of each reactance circuit, and the reactance circuits (102) are electrically connected to the loop line (902) as branching circuits along the circumference direction of the loop line (902) at equal electrical length intervals.

Abstract: The present invention discloses a cryogenic receiving amplifier using a gallium nitride high electron mobility transistor (GaN HEMT) as an amplifying device in a cryogenic temperature environment. The cryogenic receiving amplifier includes an input matching circuit which makes an impedance matching between a gate of the amplifying device and an outside of an input terminal, a gate biasing circuit which applies a DC voltage to the gate of the amplifying device, an output matching circuit which makes an impedance matching between a drain of the amplifying device and an outside of an output terminal, and a drain biasing circuit which applies a DC voltage to the drain of the amplifying device. The cooled temperature is preferably set to 150 K or below, and the GaN HEMT may be illuminated with light of a blue LED.

Abstract: The present invention has for its object to provide, in an environment where plural radio systems coexist, a feed forward amplifier capable of adaptively selecting a frequency band. The feed forward amplifier of the present invention comprises a distortion detection circuit and a distortion elimination circuit and has n first vector adjusters 4 which have different operating frequency bands and are inserted in a first vector adjustment path 14 of the distortion detection circuit; and n second vector adjusters 11 which have frequency bands corresponding to those of first vector adjusters 4 and are inserted in a second vector adjustment path 8 of the distortion elimination circuit. By means of a first switching means 3 selecting one first vector adjuster 4 and a second switching means 10 selecting a second vector adjuster 11, the frequency band for which distortion component is compensated in the feed forward amplifier is controlled by switching.

Abstract: A coupling structure for coupling to a circuit portion (6) in a coplanar-waveguide circuit (1) having ground conductors (2, 3) at both sides is disclosed. A signal input/output line (4) is provided at the center of the coplanar-waveguide circuit; and an inductive coupling portion (5) having an end of the signal input/output line short-circuited to one of the ground conductors and facing a part of the circuit portion via a first gap is also provided.

Abstract: There is provided a matching circuit, in which a main-matching block and a sub-matching block are connected in series. The sub-matching block includes: a series matching block of which one end is connected to the main-matching block; and a parallel matching network connected to the other end of the series matching block. At a first frequency f1, the connection point of the series matching block and a first parallel matching block is caused to be in an open state for a radio-frequency signal, and the connection point of the first parallel matching block and the second parallel matching block is caused to be in a short state for the radio-frequency signal. Impedance matching is performed by the main-matching block and the series matching block at the first frequency f1, and is performed by the main-matching block and the sub-matching block at the second frequency f2.

Abstract: The present invention has for its object to provide a bias circuit capable of handling multiple frequency bands, which has a low number of parts and can be miniaturized. As a solving means therefor, the bias circuit of the present invention comprises: a first reactance means 2 and a second reactance means 5, one end each of which is connected to a bias point 210 to which an alternating current signal is supplied; a capacitive means 3 connecting the other end of first reactance means 2; and a direct-current circuit 4 supplying a direct-current bias signal to the connection point of first reactance means 2 and capacitive means 3. Then, the reactance values of first and second reactance means 2, 5 have been set so as to make the combined admittance, seen from the alternating current signal supply point toward the side of first reactance element 2 and second reactance element 5, zero.

Abstract: A matching circuit includes a demultiplexer for demultiplexing a signal outputted from an amplification device into signals of respective frequency bands, and at least two matching blocks which are connected to the demultiplexer, are respectively fed with the signals of the respective frequency bands, and perform impedance matching in the respective frequency bands of the inputted signals. Impedance matching is performed on each of the demultiplexed signals of the respective frequency bands, thereby achieving a matching circuit capable of efficiently performing impedance matching in the respective frequency bands. With this matching circuit, it is possible to achieve a multi-band amplifier capable of simultaneously amplifying signals of multiple frequency bands with high efficiency and low noise.

Abstract: A filter is provided which comprises a single dielectric, and a line conductor and a ground conductor disposed on the dielectric. The line conductor includes first and second line conductor sections having opposed portions defining an open gap therebetween to form a capacitive coupling section. The edge lines of the opposed portions of the first and second conductor sections defining the open gap therebetween are substantially elongated relative to the line width of the corresponding conductor sections. The thus constructed filter is capable of suppressing a variation in the normalized J-inverter value even if dimensional errors relative to the design specifications due to overetching or underetching involved during the manufacture.

Abstract: A bias circuit 100 comprises: a first reactance means 2 connected to an AC circuit; a second reactance means 3 connected to the first reactance means 2; a switch 7 connected to a connection point 210 between them; a third reactance means 8 connected to the switch 7; a capacitive means 4 connected to the second reactance means 3; and a DC circuit 5 connected to a connection point 220between the second reactance means 3 and the capacitive means 4; wherein the connection point 220 is grounded in terms of alternating current. The connection point 210 is at a position such that impedance as viewed from the connection point 210 toward the capacitive means 4 is sufficiently large at a second frequency different from a first frequency. Impedance as viewed from a bias point 800 toward the bias circuit is sufficiently large at any of the frequencies.

Abstract: A variable resonator includes a ring-shaped conductor line (2) which is provided on a dielectric substrate (5) and has a circumferential length of a wavelength at a resonance frequency or an integral multiple of the wavelength, and at least two circuit switches (31, 32), wherein the circuit switches (31, 32) have one ends (31) electrically connected to the ring-shaped conductor line (2) and the other ends (32) electrically connected to a ground conductor (4) formed on the dielectric substrate (5), electrical connection/disconnection between the ground conductor (4) and ring-shaped conductor line (2) can be switched, and the one ends (31) of the circuit switches (31, 32) are connected to the ring-shaped conductor line (2) on different portions.

Abstract: The present invention has for its object to provide, in an environment where plural radio systems coexist, a feed forward amplifier for multiple frequency bands, capable of adaptively selecting the frequency band which is used. The feed forward amplifier of the present invention comprises a distortion detection circuit and a distortion elimination circuit and has first and second variable frequency band extractors 25a and 25b provided in series with respective vector adjustment paths 21a and 21b. Also, the feed forward amplifier comprises a frequency band controller which varies the frequency band of variable frequency band extractors 25a and 25b and has been designed, by changing the frequency band of first and second variable frequency band extractors 25a and 25b in response to a frequency switching request from the outside, to be able to adaptively control the frequency band in which distortion is compensated.

Abstract: The invention relates to a high sensitivity receiver installed outdoors which may be used in a base station of a mobile communication system, for example. A received radio frequency signal is converted into a signal in a desired frequency band by a reception bandpass filter RXF3, is subject to a low noise amplification to a desired level by a low noise reception amplifier LNA4, and the amplified signal is converted into an optical signal by a laser diode LD5. RXF3, LNA4 and LD5 are confined in a heat shielding box. LD5 is cooled by cooling means to the order of critical temperature where RXF3, for example, assumes a superconducting state, whereby the dynamic range is increased and stabilized.