Abstract: A delay circuit in which amplitude characteristic and delay time characteristic of the output signals do not have any ripple relative to the length of the transmission line is provided. The delay circuit includes a circuit that makes a part of signals distributed into two parts by the power divider (103) to be identical in amplitude and inverse in phase relative to the component of signals outputted from the terminal-a directly to the terminal-c of the circulator (104). By composing with the power combiner (107) both signals are offset each other at the output terminal. As a result, only the signals that are inputted from the input terminal (101) and transmitted through the circulator (104) and the open-ended transmission line (105) are outputted to the output terminal (102).

Abstract: A predistortion linearizer has

Abstract: The ground conductor, the side conductor, and the ceiling conductor surround the antenna element, which is connected to the coaxial power supply part arranged on the surface of the ground conductor. The ceiling conductor is arranged to face the ground conductor with the antenna element therebetween. The ceiling conductor is provided with an opening whose size, shape, and position are changed to vary the directivity of radio waves.

Abstract: A feedforward amplifier includes a first power splitter for dividing an input signal into two paths. The first path, in sequence, includes a first vector adjuster, a main amplifier, a second power splitter and a delay circuit. The second path, in sequence, includes a delay circuit, a distortion detecting power combiner, a second vector adjuster and an error amplifier. The distortion detecting power combiner combines a portion of a signal from the first path with a signal in the second path. Each vector adjuster adjusts amplitude and phase of a signal in each path. A distortion suppression power combiner synthesizes a signal in the first path with a signal in the second path. Control is included for stopping operation of the error amplifier or main amplifier based on a predetermined condition.

Abstract: A power amplifier that reduces intermodulation distortion generated by the amplifier while reducing the number of parts is provided. A power amplifier comprises a first balun, to which a combined signal combining two signals of different frequencies is inputted, and which outputs, based on the combined signal, the first and the second signal whose phase are opposite; a first amplifier that outputs the first amplified signal containing the differential frequency component comprising the difference of the frequencies of two signals from the first signal; a second amplifier that outputs the second amplified signal containing the component comprising the difference of the frequencies of two signals from the second signal; and a second balun that outputs the combined signal of the first and the second amplified signals. The component contained in the first and the second amplified signal are inputted via the second and the first amplifier, respectively, to reduce the component.

Abstract: A patch antenna apparatus with a simple structure can obtain an improved desired projection area in accordance with a projection space. The patch has a dielectric substrate with a grounding conductor on its bottom surface. On the dielectric substrate is formed at least one conductor patch having a first feeding point for producing resonance in parallel to the X-axis at a predetermined resonance frequency and a second feeding point for producing resonance in parallel to the Y-axis at the resonance frequency. A controller for a power distributing and combining circuit controls each of radio signals of the resonance frequency fed to the first and second feeding points so as to change at least one of the amplitude and phase thereof.

Abstract: A multi-filar helical antenna has an antenna radiant section which has n elements which are wound in spiral, and a phase control part which feeds signal to the n elements with a phase delay of 360°/n each in the order of an arrangement of the n elements or a phase lead of 360°/n each in the order of the arrangement of the n elements.

Abstract: Signal input units 105a to 108a of antenna elements 105 to 108 are held on the essentially same circumference. Signal output units 113b, 113c, 114b, and 114c of a feeding circuit 102 are held on a line which is located perpendicular to a plane where the above-described circumference is located, and also which passes through an essential center of this circumference. The feeding circuit 102 supplies feeding signals to the antenna elements 105 to 108 while applying predetermined phase differences to these feeding signals. As a result, electric lengths of feeding lines 119A to 119D are made coincident with each other. These feeding lines are to connect the signal output units 113b, 113c, 114c to the signal input units 105a to 108a.

Abstract: A radio antenna is disclosed with improvement in a radiation efficiency obtained by changing a directivity pattern of an antenna toward a direction not interfered by an obstacle and thus reducing radio wave interference by the obstacle. A whip antenna is connected to a transceiver unit in a radio set housing through a feeder line. A passive element is grounded to the radio set housing through a load impedance element. The whip antenna changes the horizontal directivity pattern in dependence upon the electromagnetic coupling with the passive element. The passive element operates as a wave director or a reflector for the whip antenna in accordance with the value of the load impedance element. When the passive element operates as a wave director, the radiation becomes much stronger in the direction toward the passive element. On the other hand, when the passive element operates as a reflector, the radiation in the direction away from the passive element becomes much stronger.

Abstract: A disk-shaped conductor 22, a ring-shaped conductor 24 and a ring-shaped conductor 26 are arranged in that order on the same plane. One end of a linear conductor 21 is connected perpendicularly to the center of the disk-shaped conductor 22, and the outer edge of the disk-shaped conductor 22 is connected to the inner edge of the ring-shaped conductor 24 via an anti-resonance circuit 23. Moreover, the outer edge of the ring-shaped conductor 24 is connected to the inner edge of the ring-shaped conductor 26 via an anti-resonance circuit 25.

Abstract: A filter with a low-noise amplifier includes: two amplification circuits, a first 3-dB hybrid circuit which is connected to an input side of the amplification circuits, a second 3-dB hybrid circuit which is connected to an output side of the amplification circuits, and a filter which is connected to one input terminal of the first 3-dB hybrid circuit. The other input terminal of the first 3-dB hybrid circuit is subjected to matched termination. A signal is inputted to an input terminal of the filter and is outputted from one output terminal of the second 3-dB hybrid circuit and the other output terminal of the second 3-dB hybrid circuit is subjected to matched termination.