Nippon Telegraph and Telephone Corporation

Kenjiro Nishikawa

Tsuneo Tokumitsu

Ichihiko Toyoda

Kenji Kamogawa

Kazuhiro Uehara

Tomohiro Seki

Yo Yamaguchi

Kouichi Tsunekawa

Munenari Kawashima

Naoki Honma

You Yamaguchi

A wideband low-noise amplifier of the present invention is designed such that an input terminal is connected to a base of a first transistor, one terminal of a first passive element, and one terminal of a third passive element; an emitter of the first transistor is grounded; a collector of the first transistor is connected to an output terminal, a base of a second transistor, one terminal of a capacitor, and one terminal of a second passive element; the other terminal of the first passive element is connected to the other terminal of the capacitor; an emitter of the second transistor is connected to the other terminal of the third passive element; and a power terminal is connected to a collector of the second transistor and the other terminal of the second passive element, wherein impedance of the third passive element is determined based on impedance of the first transistor whose emitter size is determined to suite desired saturation level of amplification, thus establishing input impedance matching.

Wideband low-noise amplifier

A small antenna device having an increased gain is provided. The antenna device includes a multilayer dielectric substrate composed of a combination of a plurality of dielectric layers, wherein a feeding antenna is provided in a lower layer of the multilayer substrate, a reflective metal plate is provided above the feeding antenna, and circular or rectangular metal loops are arranged so as to be of increasing diameter from lower layers toward upper layers in the plurality of dielectric layers.

Antenna device, array antenna device using the antenna device, module, module array and package module

A Marchand balun cirucit having a pair of coupled lines of quarter wavelength for dividing and/or combining signals with the same amplitude and opposite phase with each other is improved by inserting a cancellation element between said pair of coupled lines. Said cancellation element may be a transmission line, a capacitor, or an inductor which improves amplitude difference error and phase difference error of a pair of outputs by controlling phase velocity for an even mode so that phase velocity for an even mode becomes equal to that for an odd mode. Thus, a balun circuit with wide operation band, and less error of amplitude difference and phase difference is obtained.

Balun circuit with a cancellation element in each coupled line

A voltage controlled oscillator for wide tuning range of frequency with less phase noise has a bipolar transistor provided with a positive feedback circuit between a base and an emitter of the transistor, an impedance matching circuit coupled with a collector of the transistor and an output terminal, a resistor coupled between the base of the transistor and a control source which provides control voltage for adjusting oscillation frequency of the oscillator. The base of the transistor shows capacitive negative impedance, and an inductive element is coupled with the base of the transistor for oscillation. The emitter of the transistor is grounded for D.C. voltage through an inductor or a transmission line, or coupled with a control voltage.

Fully monolithic voltage controlled oscillator with wide tuning range

A monolithic integrated circuit utilizing areas associated with unused devices for wiring signal lines, thereby implementing effective wiring and improving high frequency characteristics. A common substrate consisting of a semiconductor substrate, and active devices, capacitor electrodes and resistors formed on the semiconductor substrate, is followed by a dielectric film, a ground metal, a dielectric film whose thickness is equal to or greater than 1 .mu.m, and signal lines. A desired circuit is formed by connecting the signal lines with electrodes of the active devices and other elements via, holes in the dielectric films, and windows of the ground metal. The windows of the ground metal are formed over portions of active devices which are used as components of the circuit.

High frequency masterslice monolithic integrated circuit

A variable gain amplifier circuit in which a feedback circuit that feeds back the output signal of an amplifier from its output terminal to its input terminal is composed of an FET. The gate terminal of the feedback FET is connected to the output terminal of the amplifier through a capacitor, and the source terminal of the feedback FET is connected to the input terminal of the amplifier. The gain of the amplifying circuit is controlled by varying the transconductance of the feedback FET by controlling a bias voltage applied to the gate or drain terminal of the feedback FET. This makes it possible to control the gain independently of the physical dimension of the feedback FET, and at the same time, to prevent the input signal from being transmitted from the input side to the output side through the feedback circuit.

Negative feedback variable gain amplifier circuit

A hybrid including a substrate, a first dielectric layer, a ground metal, and a second dielectric layer, which are stacked in this order. Transmission lines are formed below and above the ground metal, and a slit is formed in the ground metal at a position corresponding to projection of the transmission lines onto the ground metal. The substrate has a greater dielectric constant than the dielectric layers. This makes it possible to prevent coupling between the upper and lower transmission lines, thereby implementing a high impedance, low loss transmission lines.

Growing community of inventors

Yokosuka, Japan

Kenjiro Nishikawa