Nec Corporation

Shuya Kishimoto

Kenichi Maruhashi

Masaharu Ito

Yasuhiro Hamada

Keiichi Ohata

Takao Morimoto

Masahiro Tanomura

Kenichi Hosoya

Naoyuki Orihashi

In a phased array antenna radio communication apparatus including a plurality of antennas, a radio communication apparatus is provided which can reduce an influence of the local leak signals on the radiation direction of transmission signals. Local signal phase shifters-to-are used to control phases of local signals to be input to quadrature modulators-to-, and baseband signal phase shifters-to-are used to control phases of baseband signals to be input to the quadrature modulators-to-. The radiation direction of the local leak signals to be sent from transmission antennas-to-can be controlled by the local signal phase shifters-to-, and the radiation direction of the transmission signals can be controlled by both of the local signal phase shifters-to-and the baseband signal phase shifters-to-

Radio communication apparatus, transmitter, and radio communication method

A bias circuit according to the present invention includes a resistor layerwhich is placed above a substrateand connected to a ground potential, and a conductorfor forming an inductorplaced above the resistor layer. Further, a manufacturing method of the bias circuit according to the present invention generates the resistor layerabove the substrateand is connected to the ground potential, and generates the conductorfor forming the inductorabove the resistor layer. The present invention can provide a bias circuit and a manufacturing method of the bias circuit that enables easy integration on a semiconductor substrate and prevents parasitic oscillation.

Bias circuit and method of manufacturing the same

A phase shifter includes controlling a phase of an output signal of an orthogonal modulator; and interchanging two kinds of signals inputted to the orthogonal modulator, interchanging each polarity of the two kinds of signals inputted to the orthogonal modulator, or interchanging both of the above. The two kinds of signals inputted to the orthogonal modulator are two pairs of differential signals.

Phase shifter and method for controlling same, and radio communication device with array antenna

A 0-to-90-degree phase shifter () includes a voltage-variable power supply (), a transistor (), a 90-degree divider (), gain-variable amplifiers () (-and-), and a combiner (). The 90-degree divider () divides an input signal into a signal to which a 90-degree phase is given and a signal to which no phase is given, and outputs the divided signals to the gain-variable amplifiers (). The gain-variable amplifiers () (-and-) output signals whose amplitudes are changed according to a phase control amount to the combiner (). The combiner () combines the signals input from the two gain-variable amplifiers () and outputs the combined signal. The impedance between the source and the drain of the transistor connected to the isolation port of the 90-degree divider () can be changed as appropriate.

Phase shifter having transistor of which impedance is changeable according to phase control amount

Disclosed are a phase shifter, a wireless communication apparatus, and a phase control method in which power consumption is reduced. A phase shifter includes a 90&#xb0; step phase shifter () and a 45&#xb0; phase shifter () and adds phase information to two baseband signals to be output to an orthogonal modulator. The 90&#xb0; step phase shifter () contributes to adding any one of phases 0&#xb0;, 90&#xb0;, 180&#xb0;, and 270&#xb0; to the baseband signals according to a first control signal. The 45&#xb0; phase shifter () contributes to adding one of phases 0&#xb0; and 45&#xb0; to the baseband signals according to a second control signal. A phase shifter () performs replacement of component signals of one of the baseband signals with component signals of the other of the baseband signals and inversion of polarities of the component signals.

Phase shifter, wireless communication apparatus, and phase control method

To reduce time to point a directional wireless portable terminal (WPT) to an access point (AP) when data is downloaded from the AP to the WPT, a user points the WPT to the AP, performs a first operation and transmits a request of authentication and download to the AP. The AP requests a server to perform the authentication and the download. The server transmits information on a current situation to the AP. The AP calculates time required until the download can be started based on content capacity and the like and transmits information on the calculated time to the WPT. The WPT displays countdown until the download can be started. During that time, the server performs the authentication and, if successful, delivers content to the AP. When the download can begin, the user performs a second operation and transmits a request of re-authentication and download to the AP.

Content delivery system using wireless portable terminal and delivery method therefor

A balun circuit comprising first through third CPW lines becoming signal I/O ports, a first differential transmission line for linking the central conductor of the second CPW line and the ground conductor of the first CPW line and for linking the ground conductor of the second CPW line and the central conductor of the first CPW line, a second differential transmission line for linking the central conductors of the first and third CPW lines and for linking the ground conductors of the first and third CPW lines, and a joint for connecting at least two ground conductors of the first through third CPW lines. The differential transmission line has a first line formed in a dielectric layer on a substrate, a second line arranged in the underlying layer, and an underlying line at a fixed potential arranged between the substrate and the second line.

Balun circuit and integrated circuit device

The present invention intends to improve communication efficiency between two communication apparatuses each engaged in the communication by full duplex communication method by using a surplus band of the one to transmission band of the other. A first bandwidth required by a first communication apparatus (A) at data transmission and a second bandwidth required by a second communication apparatus (B) at data transmission are presumed. Next, the first bandwidth presumed as mentioned is compared to a first bandwidth used which the first communication apparatus (A) currently uses and at the same time, the second bandwidth presumed as mentioned is compared to a second bandwidth used which the second communication apparatus (B) currently uses. The first bandwidth and the second bandwidth are then adjusted, and a third bandwidth which the first communication apparatus (A) uses at data transmission and a fourth bandwidth which the second communication apparatus (B) uses are determined.

Band control method and communication apparatus

A bit error rate of the reception signal is detected on the reception side, such that an n optimal modulation method and LO output power are determined in accordance with this bit error rate, and an LO output changing instruction is sent to an image signal rejection mixer on the transmission side. The image signal rejection mixer changes the phase X=&#x3b1;+&#x3b3; in response to the LO output changing instruction when power splitter () splits the LO into two components with equal amplitude and phase difference &#x3b1;, power splitter () splits the IF signal into two components with equal amplitude and phase difference &#x3b2;, and power combiner () combines RF signals with equal amplitude and phase difference &#x3b3;. By changing the X, the LO output power is controlled and the back-off amount of a transmission amplifier is changed in accordance with an optimal modulation scheme. In this event, &#x3b1;&#x2212;&#x3b2;+&#x3b3;=2n&#x3c0; (n is an integer) is set so as to maximize the image signal rejection amount.

Radio communications apparatus

An oscillator comprising a dielectric resonator (DR) has a high controllability and reproducibility of coupling between the dielectric resonator (DR) and an oscillation circuit, and an integrated circuit is reduced in size. The dielectric resonator (DR) () is composed of a dielectric substrate (), grounding conductive layers () formed on both sides of the dielectric substrate (), and via holes () for electrical connection between the conductive layers. A coupling element () composed of a slot () provided in the central portion of the grounding conductive layer () and a patch () surrounded by the slot () is coupled to the dielectric resonator (DR) (). The patch () is connected to a transmission line () on an oscillation circuit () through a bump (). The transmission line () is connected to the ground through a termination resistor (). On the oscillation circuit MMIC (), the transmission line () is connected to the gate of a transistor FET () A capacitive transmission line () for positive feedback is connected to the transistor FET (). The output of the transistor FET () is connected to a transmission line () for output through a matching circuit (). The transmission line () is bump-connected to a coplanar line () composed of a signal conductive layer () formed on an edge of the dielectric resonator (DR) () and the grounding conductive layer ().

Growing community of inventors

Tokyo, Japan

Shuya Kishimoto