Fujitsu Corporation

Fujitsu Ten Limited

Naofumi Okubo

Hiroshi Kurihara

Toshiyuki Saito

Kazuhiko Kobayashi

Toru Maniwa

Yoshiaki Kaneko

Yoshimasa Daido

Teruhisa Ninomiya

Shuji Kobayakawa

Yoshihiko Asano

Yasuyuki Tokumitsu

Osamu Isaji

Tamio Saito

Yoshihiro Kawasaki

Hiroyuki Seki

Yoji Ohashi

A single antenna is used so that time-division transmission and reception is carried out in a radar apparatus for obtaining a distance and a relative speed with respect to a target object based on a beat signal obtained by transmitting a frequency modulated signal and mixing a received signal reflected by said target object with the frequency modulated signal that is transmitted.

Radar apparatus with a simplified construction

An array antenna radar apparatus has a single front end shared by a plurality of antennas, a first switch for cyclically connecting the antennas to the front end at a prescribed switching frequency, and a second switch for cyclically connecting the output of the front end to frequency converters corresponding to the antennas. The frequency converters frequency-convert intermediate-frequency signals of the respective antennas output by the front end to baseband signals at the switching frequency. Phase shifters and amplitude adjusting units apply a phase shift or amplitude adjustment to the outputs of the frequency converters and combine the resulting signals, thereby making it possible to detect a target in a desired direction.

Radar apparatus

A linear amplifier for amplifying a composite signal of plural frequency components to improve high efficiency without lowering the efficiency of a power load, includes a nonlinear amplifier circuit to which a signal having plural different frequency components is inputted, a 2nd-order distortion arithmetic circuit for generating and outputting a 2nd-order distortion component of the signal having the plural different frequency components, and an injection unit for injecting the 2nd-order distortion component to the signal having plural different frequency components. The nonlinear amplifier amplifies the signal injected with the 2nd-order distortion component.

Linear amplifier for amplifying a composite signal of plural frequency

A FM-CW radar device is provided for frequency-modulating a high frequency signal with a modulation signal, transmitting the modulated high frequency signal, receiving a signal reflected by a target object and frequency-modulating the reflection signal with a signal generated by a local oscillator signal source provided by branching a portion of the transmitting signal. A modulator is disposed between a radar transmitting section and a transmitting antenna. The modulator modulates the transmitting signal with a second frequency which is far lower than the radar transmitting frequency and twice as much as the sum or the difference of a Doppler frequency generated by a relative propagation velocity and a beat frequency generated by a propagation delay time. A first frequency converter frequency modulates the received signal reflected by the target object with the local oscillator. A second frequency converter frequency modulates the received signal with the second frequency, the second frequency being far lower than the radar transmitting frequency and twice as much as the sum or the difference of a Doppler frequency generated by a relative propagation velocity and a beat frequency generated by a propagation delay time.

Portable FM-CW radar device with frequency conversion by first and

A constant-amplitude wave combination type amplifier includes a first amplifier outputting a first amplified output, and a second amplifier outputting a second amplified output. The constant-amplitude wave combination type amplifier also includes a first constant-amplitude wave generating circuit for combining an input wave and the second amplified output from the second amplifier and for generating a first constant-amplitude wave which is input to the first amplifier, and a second constant-amplitude wave generating circuit for combining the input wave and the first amplified output from the first amplifier and for generating a second constant-amplitude wave. Further, the constant-amplitude wave combination type amplifier includes a wave combining circuit for combining the first and second constant-amplitude waves and for generating an output wave.

Constant-amplitude wave combination type amplifier

A high frequency amplifier containing: a constant envelope signal generation circuit for transforming an input signal to form two constant envelope signals where phases of the constant envelope signals correspond to an amplitude of an envelope of the input signal; two amplifying circuits for separately amplifying two constant envelope signals; and a power synthesizing circuit for synthesizing the first and second amplified signals to generate an amplified signal of the input electric signal, and reflecting remaining components of the first and second amplified signals which remaining components remain in the above synthesizing operation, toward the first and second amplifying circuits. Further, an input impedance of the power synthesizing circuit may be controlled by shifting phases of the above reflected components by respectively predetermined amounts, or by adaptively shifting phases of the above reflected components responding to an input level, so that a total efficiency of the high frequency amplifier is maximized. The high frequency amplifier may contain, instead of the above two amplifying circuits and the power synthesizing circuit, a circuit for inverting a phase of one of the two constant envelope signals; and a single-ended push-pull amplifier circuit for receiving the other of the two constant envelope signals, and an output of the phase inversion circuit, and synthesizing the received signals to generate an amplified signal of the input electric signal.

High frequency power amplifier with high efficiency and low distortion

An amplifier circuit includes a high-gain amplifier, and a feedback circuit for extracting an unstable output having a level equal to or less than a threshold level from an amplified signal from the amplifier and for feeding back the unstable signal to the amplifier, so that the amplifier oscillates at a predetermined oscillation frequency. The amplifier circuit also includes a band rejection filter for passing signal components of the amplified signal other than an oscillation output which is obtained at the output terminal of the amplifier when the amplifier oscillates at the predetermined oscillation frequency. The signal components obtained from the band rejection filter are an output signal of the amplifier circuit.

Amplifier circuit having feedback circuit

A liquid cooling type high frequency solid state device comprising: a solid state chip; at least one matching circuit connected to the solid state chip; a carrier for mounting the solid state chip and the matching circuit, constituting a solid state circuit to be cooled; a coolant vessel for containing a liquid coolant, with a space for coolant vapor at the top thereof; and an element for condensing the coolant vapor contained in the top space of the vessel. At least a part of the solid state circuit contacts the liquid coolant for boiling and evaporating the coolant. Amplitude modulation of the solid state circuit due to the boiling of the coolant is prevented.

Liquid cooling type high frequency solid state device

A cavity resonator coupling type power distributor/power combiner can be used as a distributing amplifier or a combining unit. A first cavity resonator, having a single coupling terminal, and a second cavity resonator having a plurality of coupling terminals, are coupled by a coupling window or a coupling rod. As a result, a wide bandwidth of microwave electric power can be distributed or combined.

Cavity resonator coupling type power distributor/power combiner

A microwave power distributing and synthesizing device includes: a first base and a second base facing the first base at a predetermined distance and having a hole. A coaxial line element including an inner conductive member coaxially penetrates through the hole of the second base and is spaced from an inner wall of the hole by the second base of a predetermined distance. The coaxial line element is supported on the first base at a bottom end and forms an antenna protruding from the hole of the second base into an input waveguide at a top end. At least one electric field distributing and synthesizing member is arranged perpendicularly to the coaxial line element and a plurality of waveguides are connected to the electric field distributing and synthesizing member. Also, a microwave power amplifying apparatus includes a first microwave power distributing and synthesizing device as described above, for receiving and distributing an input microwave signal; a plurality of amplifiers connected to output ports of the first microwave power distributing and synthesizing device; and a second microwave power distributing and synthesizing device as described above, having input ports connected to the amplifiers.

Microwave power distributing and synthesizing device and microwave power

A device for distributing and combining microwave electric power which is used, for example, in a high power microwave amplifier and combines or distributes microwave electric power between a first microwave path such as a standard waveguide and a plurality of second microwave paths such as a plurality of waveguides or MIC transmission lines. The device comprises a horn whose throat portion is coupled to the first microwave path, a oversized waveguide coupled to the opening portion of the horn at one end and coupled to the plurality of the second microwave paths, and, for example, a dielectric lens, or one or more reflectors, for uniformalizing the phases of the microwave signals distributed by the horn or for adjusting the phases of the microwave signals output from the second microwave paths.

Device for distributing and combining microwave electric power

A cavity resonator coupling-type power distributor/power combiner includes a first cavity resonator operatively resonating with a cylindrical T.sub.O,n,O mode, and a plurality of second cavity resonators arranged on the periphery of the first cavity resonator and extending radially and symmetrically with respect to the first cavity resonator. The second cavity resonators each have the same shape and size so that magnetic-field coupling is established between the first cavity resonator and each of the second cavity resonators, for distributing or combining microwave power in a microwave amplifier.

Growing community of inventors

Kawasaki, Japan

Naofumi Okubo