Abstract: A wireless circuit that can be used in a plurality of frequency bands even if its duplexer is formed of current variable frequency filters is provided. The circuit includes a transmission-reception antenna 911, a variable frequency duplexer 131, a double-pole six-throw switch 923, an RFIC 180, and a controller 190 which executes switching operations in accordance with control signals. The RFIC 180 determines a pair of frequency bands for transmission and reception signals input to the variable frequency duplexer 131 and generates and sends the control signals to perform switching control operations to connect a transmission port corresponding to the determined transmission frequency band with the transmission terminal of the variable frequency duplexer 131 and to connect a reception port corresponding to the determined reception frequency band with the reception terminal of the variable frequency duplexer 131 and to perform a frequency switching operation of the variable frequency duplexer 131.

Abstract: A front-end circuit includes an RFIC, an antenna, N duplexers, N variable impedance adjustment circuits, a switch for selecting any two of the N variable impedance adjustment circuits, and a control unit which receives a control signal from the RFIC, where 2?N. The control unit executes switching operations of the N variable impedance adjustment circuits and the switch in accordance with control information. The control signal indicates to 1) control the switch to select two variable impedance adjustment circuits corresponding to a p-th frequency band and a q-th frequency band respectively, 2) control a variable impedance adjustment circuit corresponding to the p-th frequency band to increase input impedance in the q-th frequency band as viewed from the antenna side and 3) control a variable impedance adjustment circuit corresponding to the q-th frequency band to increase input impedance in the p-th frequency band as viewed from the side.

Abstract: A first line stub SB1 and one end of each of two switches SW1 and SW2 are connected to a transmission line 11L at spacings L1, L2 and L3 in order from the input end of the transmission line 11L, the other ends of the two switches are connected to a second line stub SB2, the first and second line stubs have an open end or short-circuit end, and matching at any of four frequency bands can be selected by combining on and off of the two switches SW1 and SW2.

Abstract: A wireless circuit that can be used in a plurality of frequency bands even if its duplexer is formed of current variable frequency filters is provided. The circuit includes a transmission-reception antenna 911, a variable frequency duplexer 131, a double-pole six-throw switch 923, an RFIC 180, and a controller 190 which executes switching operations in accordance with control signals. The RFIC 180 determines a pair of frequency bands for transmission and reception signals input to the variable frequency duplexer 131 and generates and sends the control signals to perform switching control operations to connect a transmission port corresponding to the determined transmission frequency band with the transmission terminal of the variable frequency duplexer 131 and to connect a reception port corresponding to the determined reception frequency band with the reception terminal of the variable frequency duplexer 131 and to perform a frequency switching operation of the variable frequency duplexer 131.

Abstract: Provided is a front-end circuit which can prevent a signal from leaking into another circuit even when signals are sent and received simultaneously in multiple frequency bands in carrier aggregation.

Abstract: An multiband resonator of the present invention includes a dielectric substrate including three or more dielectric layers, a ground conductor, a main-line conductor, a sub-line conductor, a sub open stub, a main open stub, a short-circuit conductor, a main through conductor, and a sub through conductor. The short-circuit conductor electrically connects one end of the main-line conductor to one end of the sub-line conductor and to the ground conductor. The main through conductor electrically connects the other end of the main-line conductor to one end of the main open stub that is aligned with that other end of the main-line conductor. The sub through conductor electrically connects the other end of the sub-line conductor to one end of the sub open stub that is aligned with that other end of the sub-line conductor.

Abstract: In a predistorter that can compensate an intermodulation distortion component generated in a power amplifier even when employing carrier aggregation, a linear transmission path delays and transmits an input signal. Signal generation units generate individual carrier distortion signals for respective carriers included in an input signal to output an individual carrier distortion compensation signal. A sub-signal generation unit generates a carrier inter-modulation distortion signal from the input signal and the individual carrier distortion signal and outputs a carrier inter-modulation distortion compensation signal. A signal divider divides the input signal among the linear transmission path, the signal generation units, and the sub-signal generation unit. A signal combiner combines the individual carrier distortion compensation signal and the carrier inter-modulation distortion compensation signal to generate an output signal to an amplifier.

Abstract: A switch is replaced with a parallel resonant circuit 4. More specifically, a variable resonator includes a line part 1 that includes one or more lines and has an annular shape, at least two parallel resonant circuits 4 capable of changing a characteristic, and at least three variable reactance blocks 2 capable of changing a reactance value, in which the parallel resonant circuits 4 are electrically connected to the line part 1 at one end thereof at different positions on the line part 1, and the variable reactance blocks 2 are electrically connected to the line part 1 at predetermined intervals based on an electrical length at a resonance frequency.

Abstract: A variable resonator includes a first transmission line 101, a second transmission line 102 and a plurality of switch circuits 150. The electrical length of the first transmission line 101 is equal to the electrical length of the second transmission line 102. The characteristic impedance for the even mode of the first transmission line 101 is equal to the characteristic impedance for the even mode of the second transmission line 102. The characteristic impedance for the odd mode of the first transmission line 101 is equal to the characteristic impedance for the odd mode of the second transmission line 102. Each switch circuit 150 is connected to any of the first transmission line 101 and the second transmission line 102, and one of the switch circuits 150 is turned on.

Abstract: A multimode frontend circuit of the present invention comprises two transmission paths. Each of the transmission paths comprises two input/output lines, a first transmission line having one end connected to one of the input/output lines and the other end connected to the other input/output line, a second transmission line connected to the one of the input/output lines and the other end connected to the other input/output line, and one or more termination switch circuits. The termination switch circuit or circuits comprise a switch having one end connected to one of the first and second transmission lines and a termination circuit connected to the other end of the switch. Each of the transmission lines may comprise one or more short-circuiting switches. The short-circuiting switch or switches are capable of short-circuiting between the two transmission lines at positions at the same electrical length from one of the input/output lines.

Abstract: A power series digital predistorter and a distortion compensation control method for the power series digital predistorter are capable of adjusting the coefficients of a frequency characteristic compensator at high speed. A controller in the power series digital predistorter collectively sets adjustment amounts for the phases in bands in an N-th order frequency characteristic compensator; collectively sets adjustment amounts for the amplitudes in the bands in the N-th order frequency characteristic compensator; determines whether an index indicating the degree of cancellation of a distortion component generated in a power amplifier satisfies a preset condition; and, if the index does not satisfy the condition, performs control such that the adjustment amounts for the phases and the adjustment amounts for the amplitudes are set again.

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: A bias circuit includes: a bias supply terminal 800; a parallel capacitor 3 connected at one end thereof to the bias supply terminal 800 and grounded at the other end thereof; and a parallel circuit 3L connected in parallel with the parallel capacitor 3 and connected at one end thereof to the bias supply terminal 800. Let 2?N. The parallel circuit 3L includes: a direct-current power supply connection terminal 600; N parallel inductors 21 to 2N connected in series with each other between the bias supply terminal 800 and the direct-current power supply connection terminal 600; and N?1 series resonators 91 to 9N?1. Each series resonator 91 to 9N?1 includes: a resonant capacitor 71 to 7N?1 connected at one end thereof to a connecting point between adjacent parallel inductors; and a resonant inductor 81 to 8N?1 connected at one end thereof to the other end of the resonant capacitor 71 to 7N?1 and grounded at the other end thereof.

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: A multiband matching circuit includes a first matching unit for converting an impedance in a signal path to Z0 in a first frequency band, and a second matching unit formed of a series matching section connected at one end in series with the first matching unit in the signal path, which is a transmission line whose characteristic impedance is equal to the matching impedance Z0 or a circuit equivalent to the transmission line at least in the first frequency band, and a parallel matching section connected at one end to the signal path at the other end of the series matching section and grounded at the other end. The parallel matching section is configured to open in impedance the connection point to the signal path in the first frequency band. The series matching section and the parallel matching section are designed to match an impedance in a second frequency band with Z0.

Abstract: A PAPR observation unit that measures PAPR in a distributed output of an input signal and PAPR in a combined output of a linear transmission path and a third order distortion generation path, a distortion observation unit that observes distortion in the output of a power amplifier, and a controller are provided, where the controller includes a third order out-of-band distortion compensation coefficient control unit that adjusts coefficients corresponding to an outside of an input signal band among frequency characteristic compensator coefficients on the basis of distortion observed by the distortion observation unit and a third order in-band distortion coefficient control unit that adjusts coefficients corresponding to an inside of the input signal band among frequency characteristic compensator coefficients on the basis of the observed PAPR.

Abstract: A dual-band bandpass filter according to the present invention includes a plurality of dual-band bandpass resonators. The dual-band bandpass resonator includes a central conductor having a central axis aligned with an input/output direction, a pair of grounding conductors, a central conductor short-circuit part and a pair of stub conductors that are formed on a surface of a dielectric substrate. The pair of grounding conductors are disposed on the opposite sides of the central conductor with a space interposed therebetween. The central conductor short-circuit part short-circuits the pair of grounding conductors, and one end of the central conductor is connected to the central conductor short-circuit part.

Abstract: A multiband matching circuit of the present invention includes an inductive element having one end connected to an input terminal, a first switch having one end connected to the other end of the inductive element and the other end grounded, a capacitive element having one end connected to the input terminal, a second switch having one end connected to the other end of the capacitive element and the other end grounded, a first-band matching circuit that is connected between the other end of the inductive element and a first output terminal and performs impedance matching in a first frequency band, and a second-band matching circuit that is connected between the other end of the capacitive element and a second output terminal and performs impedance matching in a second frequency band higher than the first frequency band.

Abstract: A multiband matching circuit includes a first matching unit, a second matching unit, and a third matching unit, with all units being connected in series in a signal path. Matching with target impedance is established at a first frequency by appropriately designing the first matching unit and at a second frequency by appropriately designing the second and third matching units. The second matching unit and the third matching unit are designed to make the conversion ratio of the impedance viewed from the connection point between the second matching unit and the third matching unit to a circuit element to the target impedance smaller than the conversion ratio of the impedance viewed from the connection point between the first matching unit and the second matching unit to the circuit element to the target impedance, at the second frequency.

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.