Abstract: A radio frequency power amplifier module that brings sufficient attenuation to a radio frequency signal in a bias supply line connecting a bias control part and a radio frequency power amplifier part without increasing module substrate area is aimed. At least one bonding pad 106 having a capacitance component to a ground and stitch structure inductances 108, 109 composed of a bonding wire 105 provided via the bonding pad are provided in the bias supply line connecting the bias control part and the radio frequency power amplifier part.

Abstract: An object of the present invention is to provide a radio frequency power amplifier of multi stage amplifying method that is designed to reduce instability of output power caused by electromagnetic coupling of bias supply terminals and interconnections of each stage to thereby operate stably. Another object of the present invention is to provide a radio frequency power amplifier that is designed to reduce distortion of output power caused by electromagnetic coupling of bias supply terminals and interconnections of each stage to thereby provide high efficiency.

Abstract: An object of the present invention is to provide a radio frequency power amplifier of multi stage amplifying method that is designed to reduce instability of output power caused by electromagnetic coupling of bias supply terminals and interconnections of each stage to thereby operate stably. Another object of the present invention is to provide a radio frequency power amplifier that is designed to reduce distortion of output power caused by electromagnetic coupling of bias supply terminals and interconnections of each stage to thereby provide high efficiency.

Abstract: To provide a small-sized high frequency power amplifier for preventing oscillation by a small number of switching circuits and outputting high power and low power with high efficiencies, a high frequency power amplifier module and a portable telephone, the high frequency power amplifier is constituted by an amplifying circuit A and an amplifying circuit B connected in parallel, a size of a transistor at an output stage of the amplifying circuit B is made to be equal to or smaller than ¼ of a size of a transistor of an output stage of the amplifying circuit A and a switching circuit is connected between a signal line forward from the output stage of the amplifying circuit A and a ground terminal.

Abstract: A first aspect of the invention is to realize a power amplifier having high power adding efficiency and high power gain at low cost. For that purpose, in a semiconductor device using an emitter top heterojunction bipolar transistor formed above a semiconductor substrate and having a planar shape in a ring-like shape, a structure is provided in which a base electrode is present only on an inner side of a ring-like emitter-base junction region. In this way, as a result of enabling to reduce base/collector junction capacitance per unit emitter area without using a collector top structure having complicated fabricating steps, a semiconductor device having high power adding efficiency and high-power gain and suitable for a power amplifier can be realized.

Abstract: The present invention provides a power amplifier module used in a cellular phone or the like. In the power amplifier module, a bias control circuit converts a bias voltage to a current by MOS transistors, whereby a voltage drop is reduced and the value of the bias voltage is lowered. Bias control signals outputted from the bias control circuit are inputted to a high-frequency amplifying unit through low-pass filters. The low-pass filter comprises an inductance, and a condenser. Each of the condensers attenuates an envelope frequency. Each of the inductances suppresses a change in impedance at a carrier frequency of a modulation signal.

Abstract: An object of the present invention is to provide a radio frequency power amplifier of multi stage amplifying method that is designed to reduce instability of output power caused by electromagnetic coupling of bias supply terminals and interconnections of each stage to thereby operate stably. Another object of the present invention is to provide a radio frequency power amplifier that is designed to reduce distortion of output power caused by electromagnetic coupling of bias supply terminals and interconnections of each stage to thereby provide high efficiency.

Abstract: A high frequency power amplifier is provided that prevents loop oscillation at a low frequency caused by a closed loop formed between combined semiconductor devices. Previously, coupled-line directional couplers or capacitors for low frequency rejection have been used to prevent the closed loop from being formed. Also, a circuit including a resistance component required for attenuating self-oscillation has been provided. Therefore, to prevent both loop oscillation and self oscillation, two circuits have been required. Accordingly, a high frequency power amplifier is provided with a low frequency prevention circuit that attenuates the passing of each frequency of loop oscillation and self oscillation to each signal line divided by a power divider. Thus, the two circuits respectively required for preventing the loop oscillation and self oscillation of a travelling wave combine type amplifier can be formed by one low frequency prevention circuit.

Abstract: A radio frequency module includes a first circuit board and a second circuit board. A first circuit element group is placed in a cavity formed on the upper surface of the first circuit board, and a second circuit element group is placed on the upper surface of the second circuit board. The first and second circuit boards are provided with terminal electrodes by which electrical connection is established. The radio frequency module is formed by vertically connecting the two circuit boards together. Heat emitted by the first circuit element group is transferred to a heat radiation section, which is formed on the lower surface of the first circuit board, via through-holes connecting the bottom of the cavity with the heat radiation section.

Abstract: To provide a small-sized high frequency power amplifier for preventing oscillation by a small number of switching circuits and outputting high power and low power with high efficiencies, a high frequency power amplifier module and a portable telephone, the high frequency power amplifier is constituted by an amplifying circuit A and an amplifying circuit B connected in parallel, a size of a transistor at an output stage of the amplifying circuit B is made to be equal to or smaller than ¼ of a size of a transistor of an output stage of the amplifying circuit A and a switching circuit is connected between a signal line forward from the output stage of the amplifying circuit A and a ground terminal.

Abstract: The present invention provides a radio frequency power amplifier which may not introduce radio frequency loss during switching power amplifier units between high and low output power levels. By connecting a first-stage matching network M12 and first-stage matching network M13 to respective output nodes of a power amplifier unit A11 and power amplifier unit A12 that either one operate by switching, connecting the output nodes of the first-stage matching network M12 and M13 in parallel, connecting a last-stage matching network M11 between the junction of M12 and M13 and the output terminal OUT, the first-stage matching networks M12, M13, and last-stage matching network M11 are formed, for both power amplifier units A11 and A12, so that impedance matching is established between the output terminal OUT and the power amplifier unit in operation when one unit is in operation the other is in stop of operation.

Abstract: A power combiner having a plurality of power amplifiers which are even-numbered, a plurality of series-connected branch circuits for respectively distributing input power to the plurality of power amplifiers, and a plurality of series-connected combiners for combining the respective output power of the plurality of power amplifiers. In the case of any one of such combinations as to equalize electric lengths of transmission lines for connecting between two power amplifiers selected from the plurality of power amplifiers, the combinations each being established by using all of the plurality of power amplifiers once, the electric lengths at which the any one of the combinations are established, take &lgr;/2i (where &lgr;=wavelength of fundamental wave, and i=positive integer).

Abstract: The invention provides a high frequency power amplifier that prevents loop oscillation at a low frequency which is caused by a closed loop formed between combined semiconductor devices in case plural power combine circuits are used for tournament connection. Heretofore, for a countermeasure for the loop oscillation, a coupled-line directional coupler is used or a capacitor for low frequency rejection to prevent a closed loop from being formed is inserted into each signal line and a bias circuit is provided separately. Also, as a semiconductor device causes self oscillation by impedance applied to the input and output, a circuit including a resistance component required for attenuating an oscillated signal is provided. Therefore, to prevent both loop oscillation and self oscillation, two circuits are required.

Abstract: A power combiner having a plurality of power amplifiers which are even-numbered, a plurality of series-connected branch circuits for respectively distributing input power to the plurality of power amplifiers, and a plurality of series-connected combiners for combining the respective output power of the plurality of power amplifiers. In the case of any one of such combinations as to equalize electric lengths of transmission lines for connecting between two power amplifiers selected from the plurality of power amplifiers, the combinations each being established by using all of the plurality of power amplifiers once, the electric lengths at which the any one of the combinations are established, take &lgr;/2i (where &lgr;=wavelength of fundamental wave, and i=positive integer).

Abstract: A travelling wave power combiner ensures high isolation between power amplifiers and reduces harmonic components caused by non-linearity of each power amplifier. Therefore, the travelling wave power circuit is provided with even-numbered power amplifiers, a plurality of series-connected branch circuits for respectively distributing input power to the even-numbered power amplifiers, and a plurality of series-connected combiners for combining respective output power of the even-numbered power amplifiers. With respect to all of such combinations as to equalize electric lengths of transmission lines for connecting between the power amplifiers to one another, which combinations are established for the plurality of power amplifiers, the electric lengths at which the combinations are established, take &lgr;/2i (where &lgr;=the wavelength of a fundamental wave, and i=positive integer).

Abstract: An antenna of small size is provided which can be mass-produced, which is suitable for use with a portable receiver and which does not require provision of a separate matching circuit. The antenna includes a plurality of meander antennas printed on at least one dielectric film and satisfying respectively different resonance conditions in a frequency band used by the receiver, at least one dielectric solid cylinder for winding the dielectric film therearound, and a dielectric hollow cylinder for covering the dielectric film wound around the dielectric solid cylinder. The individual meander antennas printed on the dielectric film do not make direct electrical contact with each other, and one of the meander antennas connected to a feeder or a helical antenna surrounding the dielectric solid cylinder acts to produce multiple resonance by means of electromagnetic coupling with the other meander antennas, thereby widening the frequency band.

Abstract: An antenna for radio apparatus comprises a first conductor taking a helical form, a second conductor which extends to and fro in sequence substantially in a direction of the center axis of the helical form of the first conductor to take, as a whole, a meandering form which is spaced apart from the first conductor and surrounds the center axis, and a dielectric member which lies at least between the first and second conductors. A portion of the first conductor is electrically connected to a portion of the second conductor, and either a portion of the first conductor or a portion of the second conductor acts as a feeding point.

Abstract: A high-frequency power amplifier comprises a pair of FETs, a divider which supplies opposite-phase versions of a signal to be amplified to the FETs, distributed-parameter transmission lines connected respectively at one ends thereof to output electrodes of the FETs, and a combiner which combines signals appearing at another ends of the transmission lines into a signal of a common phase. Stubs which short-circuit for even harmonics included in output signals of the FETs are connected respectively to the transmission lines at positions distant from the output electrodes of the FETs by a multiple of a quarter wavelength of the fundamental wave included in the output signals of the FETs.

Abstract: A filtering device for blood platelets comprises polyester fibers having an average cross-sectional diameter of 0.1 to 5 .mu.m, wherein there is formed electro-microscopic roughness on the surface of the polyester fibers. According to the present invention, there can be realized a filtering device for blood platelets having simple construction, wherein blood platelets are caught efficiently and the removal of blood platelets is carried out in a short time.

Abstract: Vinyl chloride monomer, or a monomeric mixture comprising vinyl chloride as a main component and other monomers co-polymerizable therewith in an aqueous reaction medium, is polymerized in a polymerization vessel. All of the surfaces of the inside walls of the vessel and the agitator blades, the baffle plates and the like with which the vessel is equipped, are coated prior to the polymerization with at least one of a specific class of nitrogen-containing aromatic heterocyclic compounds. Not only is the deposition of polymer scale surprisingly reduced, but also the polymer thus obtained has good physical and chemical properties.