Abstract: A high frequency switch configured particularly with two FET switches. One end of a second FET switch is connected between an I/O port and a reception port and the other end is ground. A strip line is connected between the second FET switch and the I/O port, and has the electrical length equivalent to {fraction (1/4 )} wavelength of the high frequency signal input from a transmission port.

Abstract: A high-frequency hybrid switch module arranged applicable to at least two different communications systems includes two low pass filters (LPFs), two phase shifters, a field effect transistor (FET) switch including FETs, and two SAW filters. The FETs and the SAW filters are mounted on a layered assembly including the LPFs and an electrode pattern of the phase shifters. The module can have a small overall size, a low cost, and a small loss, while being protected from static electricity. The module requires small number of low-noise amplifiers at a signal receiving side.

Abstract: A laminated dielectric filter is formed by coupling a plurality of resonators to one another by electromagnetic-field coupling. In the laminated dielectric filter, a bypass circuit formed of a series circuit including bypass capacitors and transmission lines is provided in parallel to a magnetic-field bypass coupling between non-adjacent resonators. Thus, capacitance of the bypass capacitors can be regulated without being affected by the magnetic-field bypass coupling between the non-adjacent resonators. As a result, attenuation poles outside a passband can be controlled freely.

Abstract: A laminated dielectric filter is formed by coupling a plurality of resonators to one another by electromagnetic-field coupling. In the laminated dielectric filter, a bypass circuit formed of a series circuit including bypass capacitors and transmission lines is provided in parallel to a magnetic-field bypass coupling between non-adjacent resonators. Thus, capacitance of the bypass capacitors can be regulated without being affected by the magnetic-field bypass coupling between the non-adjacent resonators. As a result, attenuation poles outside a passband can be controlled freely.

Abstract: A bias circuit is provided for attenuating harmonic distortions of a signal having a simple construction and which can be applied to a high-frequency amplifier used in a communication device, such as a mobile telephone. The circuit reduces a voltage drop therein and thus provides a high-frequency amplifier having reduced power consumption and an increased operating efficiency. The high-frequency amplifier includes an amplifier circuit, an output matching circuit, and the bias circuit. In the bias circuit, a parallel circuit including a first transmission line and a first capacitor has one end connected between the amplifier and the output matching circuit. The other end of the parallel circuit is connected to a power source and is grounded via a second capacitor. In the circuit, the bias circuit can be short-circuited in a desired frequency band while being an open circuit in a frequency band of a signal to be amplified, hence attenuating the harmonic distortions without using a low pass filter.

Abstract: Here disclosed is a parallel-resonance type band-pass filter, which is employed for mobile communications equipment such as a mobile phone. According to the filter, each resonator has a single capacitor and serially connected plural inductors both of which are formed on the surface or on an inner layer of a substrate. Electromagnetic coupling between the resonators is established through electromagnetic coupling between at least a pair of inductors—the inductors of the pair belong to respective resonators. The input and the output terminals are coupled with the respective resonators via the capacitor having a properly determined capacitance. With such a simple structure, the filter also can work as an impedance transformer, with the result that the mobile communications equipment will be much smaller.

Abstract: The present matching circuit chip has an integrated shape comprising a first transmission line, a second transmission line and a third transmission line, wherein one end of the first transmission line, one end of the second transmission line and one end of the third transmission line are connected to one another, a first filter connection terminal is connected to the other end of the first transmission line, an antenna terminal is connected to the other end of the second transmission line, and a second filter connection terminal is connected to the other end of the third transmission line, whereby the second transmission line converts the characteristic impedances of the first and third transmission lines so that the impedance matching between the antenna terminal and the first filter connection terminal can be attained, and so that the impedance matching between the antenna terminal and the second filter connection terminal can be attained.

Abstract: The present matching circuit chip has an integrated shape comprising a first transmission line, a second transmission line and a third transmission line, wherein one end of the first transmission line, one end of the second transmission line and one end of the third transmission line are connected to one another, a first filter connection terminal is connected to the other end of the first transmission line, an antenna terminal is connected to the other end of the second transmission line, and a second filter connection terminal is connected to the other end of the third transmission line, whereby the second transmission line converts the characteristic impedances of the first and third transmission lines so that the impedance matching between the antenna terminal and the first filter connection terminal can be attained, and so that the impedance matching between the antenna terminal and the second filter connection terminal can be attained.

Abstract: A dielectric filter, has

Abstract: Disclosed is a radio frequency filter used for a mobile communication apparatus such as a mobile phone, having an inductor component, a capacitor component, and a resistor component formed of a conductor pattern. The filter includes the conductor pattern formed on the surface of dielectric layer, and an adjusting layer for adjusting the frequency characteristic of the filter formed so as to cover at least a part of the conductor pattern. In the radio frequency filter, the conductor pattern is formed and sintered, followed by adjusting the frequency characteristic of the filter. Accordingly, in the radio frequency filter, the yield of the manufacture is improved. Further, the electrode layer can be single-layered by using extra-thin lines for the conductor pattern and interdigital electrodes for the capacitor. As a result, it is possible to make the filter smaller and thinner by using intaglio-printing technique and thin-film forming technique.

Abstract: A dielectric filter including a plurality of resonators, and at least one transmission line provided among said plurality of resonators. A band rejection characteristic is formed around a resonance frequency of the resonator, and a line length of the transmission line is shorter than ¼ of a wavelength corresponding to the resonance frequency of the resonator.

Abstract: The present invention aims to realize, in regard to a high frequency switch used for a mobile communication apparatus such as a portable telephone or the like, a dual band switch having simple structure and changeable to ON and OFF states in two bands. For realizing the aim, the present invention provide a dual band switch comprising a series circuit of a PIN diode (101) and its compensation circuit (102), and, the compensation circuit (102) is formed with a circuit having at least two series resonance points and one parallel resonance point. The above structure allows the impedance of the compensation circuit, which is capacitive in low frequency close to a direct current, to be inductive after undergoing the first series resonance point, whereby the parasitic capacity of the diode is canceled in the first band, and also to be inductive again after undergoing the parallel resonance point and the following series resonance point, whereby the parasitic capacity of the PIN diode is canceled in the second band.

Abstract: A laminated filter comprising a plurality of resonator electrodes, an inter-resonator coupling capacitor electrode for coupling adjacent resonators, and two input/output coupling capacitor electrodes for coupling input/output terminals and the resonator electrodes. This provides a capacitor electrode for electrically connecting one side of the input/output terminals with a portion of the input/output coupling capacitor electrode, wherein the input/output coupling capacitor electrode and the capacitor electrode are a parallel circuit. This structure forms a parallel resonance circuit in the input/output terminal, to provide an additional attenuation pole besides an attenuation pole formed by electromagnetic coupling between the resonators and an inter-resonator capacitance, thereby realizing a laminated filter of a high attenuation. With this structure, a duplexer can be made using a plurality of the filters of this invention without requiring a phase-shifting circuit.

Abstract: Here disclosed is a parallel-resonance type band-pass filter, which is employed for mobile communications equipment such as a mobile phone. According to the filter, each resonator has a single capacitor and serially connected plural inductors both of which are formed on the surface or on an inner layer of a substrate. Electromagnetic coupling between the resonators is established through electromagnetic coupling between at least a pair of inductors—the inductors of the pair belong to respective resonators. The input and the output terminals are coupled with the respective resonators via the capacitor having a properly determined capacitance. With such a simple structure, the filter also can work as an impedance transformer, with the result that the mobile communications equipment will be much smaller.

Abstract: Disclosed is a radio frequency filter used for a mobile communication apparatus such as a mobile phone, having an inductor component, a capacitor component, and a resistor component formed of a conductor pattern. The filter includes the conductor pattern formed on the surface of dielectric layer, and an adjusting layer for adjusting the frequency characteristic of the filter formed so as to cover at least a part of the conductor pattern. In the radio frequency filter, the conductor pattern is formed and sintered, followed by adjusting the frequency characteristic of the filter. Accordingly, in the radio frequency filter, the yield of the manufacture is improved. Further, the electrode layer can be single-layered by using extra-thin lines for the conductor pattern and interdigital electrodes for the capacitor. As a result, it is possible to make the filter smaller and thinner by using intaglio-printing technique and thin-film forming technique.

Abstract: A diplexer employed in mobile communications equipment such mobile phones which can divide signals into two channels with a simple configuration without interfering the other band. In this diplexer, an inductor 105 is connected between a &pgr;-type three-stage one polar low-pass filter 115 and a common terminal 113 as a first matching circuit, and a capacitor 106A is connected between a one polar band-pass filter 116 and a common terminal 113 as a second matching circuit so that interference with the other band can be prevented and the higher harmonics can be sufficiently attenuated with simple configuration.

Abstract: The present matching circuit chip has an integrated shape comprising a first transmission line, a second transmission line and a third transmission line, wherein one end of the first transmission line, one end of the second transmission line and one end of the third transmission line are connected to one another, a first filter connection terminal is connected to the other end of the first transmission line, an antenna terminal is connected to the other end of the second transmission line, and a second filter connection terminal is connected to the other end of the third transmission line, whereby the second transmission line converts the characteristic impedances of the first and third transmission lines so that the impedance matching between the antenna terminal and the first filter connection terminal can be attained, and so that the impedance matching between the antenna terminal and the second filter connection terminal can be attained.

Abstract: A dielectric filter, has

Abstract: The present matching circuit chip has an integrated shape comprising a first transmission line, a second transmission line and a third transmission line, wherein one end of the first transmission line, one end of the second transmission line and one end of the third transmission line are connected to one another, a first filter connection terminal is connected to the other end of the first transmission line, an antenna terminal is connected to the other end of the second transmission line, and a second filter connection terminal is connected to the other end of the third transmission line, whereby the second transmission line converts the characteristic impedances of the first and third transmission lines so that the impedance matching between the antenna terminal and the first filter connection terminal can be attained, and so that the impedance matching between the antenna terminal and the second filter connection terminal can be attained.

Abstract: The present matching circuit chip has an integrated shape comprising a first transmission line, a second transmission line and a third transmission line, wherein one end of the first transmission line, one end of the second transmission line and one end of the third transmission line are connected to one another, a first filter connection terminal is connected to the other end of the first transmission line, an antenna terminal is connected to the other end of the second transmission line, and a second filter connection terminal is connected to the other end of the third transmission line, whereby the second transmission line converts the characteristic impedances of the first and third transmission lines so that the impedance matching between the antenna terminal and the first filter connection terminal can be attained, and so that the impedance matching between the antenna terminal and the second filter connection terminal can be attained.