Abstract: A power amplifier of the present invention comprises MOS transistor (1) having a gate length of 180 nm or less, and output matching circuit (5) connected to a drain terminal of MOS transistor (1). Also, MOS transistor (1) is applied with voltage Vd_n normalized by a voltage value allowable in a DC state as a drain-source voltage, where Vd_n is in a range of 0.5 to 0.9. ZL (=RH+j·XL) represents a value equal to a load impedance when viewing the output matching circuit (5) from the drain terminal normalized by gate width W (mm) of MOS transistor (1), and a real part (RL) of the ZL is RL>0.64×Vd_n+0.19 (?· mm), and RL<0.64×Vd_n+1.73 (?· mm).

Abstract: 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=?+? in response to the LO output changing instruction when power splitter (201) splits the LO into two components with equal amplitude and phase difference ?, power splitter (202) splits the IF signal into two components with equal amplitude and phase difference ?, and power combiner (205) combines RF signals with equal amplitude and phase difference ?. 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, ???+?=2n? (n is an integer) is set so as to maximize the image signal rejection amount.

Abstract: A balun circuit includes a first CPW line 11, a second CPW line 12a, and a third CPW line 12b that serve as signal input/output ports; a first CPS line 14a that is a differential transmission line, the first CPS line 14a relaying the first CPW line 11 to the second CPW line 12a; a second CPS line 14b that is a differential transmission line, the second CPS line 14b relaying the first CPW line 11 to the third CPW line 12b; and at least one connection section that connects grounded conductors of each of the first CPW line 11, the second CPW line 12a, and the third CPW line 12b.

Abstract: A method of controlling a wireless communication system including a plurality of communication devices is disclosed. In the method, firstly, one of the communication devices establishes a fixed beam pattern and transmits a training signal, and another communication device receives the training signal while scanning a beam direction by changing the AWVs of an antenna array. Next, it obtains a data string describing a relation between an incoming direction and a received-signal characteristic at the other communication device based on a reception result of the training signal. Then, it obtains first AWVs with which a beam is formed in a plurality of incoming directions of the received signal based on the data string. The roles of these two communication devices are interchanged and similar processes are performed in order to obtain second AWVs, and then one of AWV combinations combining first and second AWVs are used for wireless communication between these communication devices.

Abstract: 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.

Abstract: Provided is a radio control method for a radio communication being performed in a beam direction that is set on the basis communication quality basis, including a step of acquiring a data string formed of at least a beam direction and communication quality in the beam direction; and a step of sequentially assigning a priority rank for setting the beam direction for performing the radio communication from the beam direction in which the highest communication quality is obtained, according to the data string. In the step of assigning a priority rank, no priority rank is assigned to the beam direction adjacent to the beam direction to which a priority rank has been already assigned or to the beam direction in the vicinity containing the adjacent beam direction.

Abstract: 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.

Abstract: A balun circuit includes a first CPW line 11, a second CPW line 12a, and a third CPW line 12b that serve as signal input/output ports; a first CPS line 14a that is a differential transmission line, the first CPS line 14a relaying the first CPW line 11 to the second CPW line 12a; a second CPS line 14b that is a differential transmission line, the second CPS line 14b relaying the first CPW line 11 to the third CPW line 12b; and at least one connection section that connects grounded conductors of each of the first CPW line 11, the second CPW line 12a, and the third CPW line 12b.

Abstract: 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) (1) is composed of a dielectric substrate (2), grounding conductive layers (3a, 3b) formed on both sides of the dielectric substrate (2), and via holes (4a) for electrical connection between the conductive layers. A coupling element (7a) composed of a slot (5a) provided in the central portion of the grounding conductive layer (3a) and a patch (6a) surrounded by the slot (5a) is coupled to the dielectric resonator (DR) (1). The patch (6a) is connected to a transmission line (13a) on an oscillation circuit (9) through a bump (8). The transmission line (13a) is connected to the ground through a termination resistor (15a).

Abstract: 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=?+? in response to the LO output changing instruction when power splitter (201) splits the LO into two components with equal amplitude and phase difference ?, power splitter (202) splits the IF signal into two components with equal amplitude and phase difference ?, and power combiner (205) combines RF signals with equal amplitude and phase difference ?. 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, ???+?=2n? (n is an integer) is set so as to maximize the image signal rejection amount.

Abstract: A radio communications device includes a transmitter, a receiver, a propagation detecting unit, and a symbol rate setting unit. The receiver has a plurality of antennas, a plurality of transmitting circuits, and a transmission signal processing circuit. The transmission signal processing circuit has a modulator, and modulates data input transmission data in modulator to output the modulated data as transmission signal to the transmitting circuits. The receiver has a plurality of antennas, a plurality of receiving circuits, and a reception signal processing circuit. The reception signal processing circuit has a demodulator, demodulates reception signals input from the receiving circuits in demodulator to generate reception data. The propagation detecting unit detects propagation state of radio waves. The symbol rate setting unit selects a symbol to be communicated from a plurality of symbol rates based on the detected propagating state and sets the selected symbol rate to the modulator and to the demodulator.

Abstract: The present invention provides a filter exhibiting excellent filter characteristics and having less number of stages. A dielectric substrate (1) has one surface connected to a top conductor (2) and an opposite surface connected to a bottom conductor (3). A pair of rows of via-holes connecting together the top conductor (2) and the bottom conductor (3) are formed along the signal transfer direction. A slit (6) is formed in a portion of the top conductor (2) overlying the central resonator among a plurality of resonators. The slit (6) extends in a direction perpendicular to the signal transfer direction. Slits (7, 8) are formed in each of portions of the top conductor (2) overlying resonators disposed at both ends. A coplanar waveguide (9) mounted on the top conductor (2) is connected to the slit (7).

Abstract: A conductive layer is formed on each of the upper and lower surfaces of a dielectric substrate, and the two conductive layers are connected by rows of via-holes that are formed which a spacing that is less than or equal to ½ of the wavelength in the dielectric substrate in the resonance frequency, whereby n stages of dielectric resonators and input/output waveguide structures are formed. If the number n of stages is assumed to be 3, the first-stage resonator and the second-stage resonator are coupled by an electromagnetic field by means of via-holes of a first spacing; the second-stage resonator and the third-stage resonator are coupled by an electromagnetic by means of via-holes of a second spacing, whereby a filter is formed. The input/output waveguide structure and the filter are coupled by an electromagnetic by means of via-holes of a fourth spacing. The first-stage resonator and the third-stage resonator are coupled by an electromagnetic field by means of via-holes of a third spacing.

Abstract: In the sector antenna of the present invention, a feeder waveguide is formed that branches midway from a feeder port to each of a plurality of antennas. This feeder waveguide is formed from a waveguide tube and includes a main feeder line that extends from a waveguide that extends from the feeder port and branches in two directions, and branch feeder lines that each branch in two directions from the two ends of the main feeder line. Sector selection structures are provided for selectively shutting off each branch waveguide by effectively forming conductive walls for blocking the cross section of each of the branch waveguides at positions of each of the branch feeder lines that branch and extend from the main feeder line and from which each branch waveguide begins.

Abstract: A dielectric waveguide tube band-pass filter assuming lower characteristic change upon mounting, and having smaller dimensions and lower loss. Conductor layers (2a, 2c) are formed on the top and bottom surfaces of a dielectric substrate (1), wherein the top conductor layer 2a and the bottom conductor layer 2c are connected together through via-holes (3a). The via-holes (3a) are formed in at least two rows along the signal transfer direction. In the dielectric waveguide tube configured by the top and bottom conductor layers (2a, 2c) and the via-holes (3a), via-holes (3b) are arranged in the signal transfer direction at spacing equal to or below ½ of the in-tube wavelength to thereby configure resonators. The dielectric band-pass filter is configured by coupling adjacent resonators together through the via-holes (3b) configuring inductive windows.

Abstract: 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) (1) is composed of a dielectric substrate (2), grounding conductive layers (3a, 3b) formed on both sides of the dielectric substrate (2), and via holes (4a) for electrical connection between the conductive layers. A coupling element (7a) composed of a slot (5a) provided in the central portion of the grounding conductive layer (3a) and a patch (6a) surrounded by the slot (5a) is coupled to the dielectric resonator (DR) (1). The patch (6a) is connected to a transmission line (13a) on an oscillation circuit (9) through a bump (8). The transmission line (13a) is connected to the ground through a termination resistor (15a).

Abstract: A negative resistance circuit having a transistor and a plurality of distributed constant lines respectively connected to the three terminals of the transistor further comprises an inductive element or a capacitive element connected between the output terminal of the negative resistance circuit and the ground potential. The negative resistance is adjusted through the inductance of the inductive element or the capacitance of the capacitive element.

Abstract: A conductive layer is formed on each of the upper and lower surfaces of a dielectric substrate, and the two conductive layers are connected by rows of via-holes that are formed which a spacing that is less than or equal to ½ of the wavelength in the dielectric substrate in the resonance frequency, whereby n stages of dielectric resonators and input/output waveguide structures are formed. If the number n of stages is assumed to be 3, the first-stage resonator and the second-stage resonator are coupled by an electromagnetic field by means of via-holes of a first spacing; the second-stage resonator and the third-stage resonator are coupled by an electromagnetic by means of via-holes of a second spacing, whereby a filter is formed. The input/output waveguide structure and the filter are coupled by an electromagnetic by means of via-holes of a fourth spacing. The first-stage resonator and the third-stage resonator are coupled by an electromagnetic field by means of via-holes of a third spacing.

Abstract: A high frequency circuit substrate comprises a first high frequency circuit substrate including at least a first dielectric material layer, a first conductor layer, a second dielectric material layer and a second conductor layer, which are laminated in the named order, the first conductor layer having a first slot formed therein, and the second conductor layer forming a transmission line, the first dielectric material layer having a first opening exposing the first slot at its bottom. The high frequency circuit substrate also comprises a second high frequency circuit substrate including at least a third dielectric material layer, a third conductor layer, a fourth dielectric material layer and a fourth conductor layer, which are laminated in the named order, the third conductor layer having a second slot formed therein, and the fourth conductor layer forming a transmission line, the third dielectric material layer having a second opening exposing the second slot at its bottom.

Abstract: An RF package includes a multilayered dielectric substrate, a feed-through, and metal members. First and second dielectric substrates are formed on the multilayered dielectric substrate. The multilayered dielectric substrate has a cavity where a semiconductor element is to be mounted. The feed-through connects the inside and outside of the cavity and is comprised of a coplanar line formed on the first dielectric substrate and an inner layer line obtained by forming the second dielectric substrate on the coplanar line. The coplanar line and the inner layer line share a strip-like signal conductor. The metal members are formed at a connection interface between the coplanar line and the inner layer line on two sides of the signal conductor.