Nec Corporation

The University of Electro-Communications

Teijin Limited

Casio Computer Co., Ltd.

Campus Create Co., Ltd.

Ykc Corporation

Kazuhiko Honjo

Akira Saitou

Ryo Ishikawa

Sadao Kadokura

Yutaka Aoki

Takashi Tomie

Masahiko Naoe

Hiroto Otsuka

Yoichiro Takayama

Akira Saito

Masahiko Sekiya

Kazuhiro Kamei

Shin-ichi Tanaka

Kenta Kuroda

Masahiro Kamiyama

Atsushi Oyamatsu

A wireless communication apparatus includes a transmitting antenna; and a receiving antenna that receives a wireless signal transmitted from the transmitting antenna. Each of the transmitting antenna and the receiving antenna includes a plurality of circular loop antennas arranged concentrically in an identical plane, each of the plurality of circular loop antennas having a loop perimeter approximately equal to an integer multiple of one wavelength determined from a frequency in a wireless communication; and a plurality of feeding sections individually connected with the plurality of circular loop antennas. A central axis of the plurality of circular loop antennas of the transmitting antenna and a central axis of the plurality of circular loop antennas of the receiving antenna are arranged approximately on a straight line. Thus, a wireless signal is transmitted between the circular loop antennas having a loop perimeter of a transmitting side and a receiving side.

Wireless communication device and antenna device

Circular loop antenna elements of each of a transmitting antennaand a receiving antennahave different perimeters of approximately integral multiples of a wavelength determined from a wireless communication frequency. The transmitting antennaand the receiving antennainclude first circular loop antenna groupsA andA concentrically disposed on the same plane and second circular loop antenna groupsB andB including circular loop antenna elements of the same perimeter as that of a plurality of circular loop antenna elements of the first circular loop antenna group. An angular position of a terminal for connecting power supply units to circular loop antenna elements having the same perimeter is set to an angular position rotated by (2l+1)&#x3c0;/2m(where l is any integer, and mis a value of mto mthat are approximately integral multiples of a wavelength) in the first and second circular loop antenna groups.

Wireless communication apparatus and antenna device

A concurrent-type multiband amplifier (or a dual-band amplifier) which amplifies multiband signals concurrently using a plurality of (N) amplifier circuits which each independently amplify signals in a plurality of (N) frequency bands. An n-th (n=any of 1 to N) amplifier circuit is provided with a circuit for blocking signals in frequency bands other than the n-th frequency band so as to amplify and output only the n-th frequency band signal. The n-th amplifier circuit is designed so as to consist of its input/output impedance matching circuit for the n-th an amplifier element at the n-th frequency band.

Dual-band amplifier

A high efficiency power amplifier of the present invention includes a transistor and an output power processing circuit section. The output power processing circuit section includes an output matching circuit section and an output harmonic processing circuit section. The output matching circuit section carries out impedance matching to the fundamental wave component of the output power. The output harmonic processing circuit section carries out a reactive power control to a reactive power of a plurality of harmonic power components respectively having a plurality of harmonic angular frequencies which are integral multiples of the base angular frequency of the output power. The output harmonic processing circuit section is formed to realize the reactive power control to at least one of the plurality of harmonic power components by orthogonalizing the phases of the current and voltage in the reactive power.

High efficiency power amplifier

A multi-frequency circularly polarized antenna () comprises a substrate and multi-frequency antennas (). The multi-frequency antennas () comprise antenna elements (), shunt-inductor conductors (), series-capacitor conductors (), series-inductor capacitors (), a center point () and input/output terminals (). The multi-frequency circularly polarized antenna () is constructed by connecting the shunt-inductor conductors () of the multi-frequency antennas () at the center point () in a substantially perpendicular manner.

Antenna

A multi-frequency antenna () comprises a dielectric substrate (), an antenna element (), a shunt inductor (), a capacitor conductor (), a series inductor (), a grounded part () and a feeding point (). The antenna element () is arranged on the substrate (), and is electrically connected to the grounded part () through the shunt inductor (). Moreover, the antenna element () is electrically connected to the feeding point () through a series capacitor formed by a part where the antenna element () faces the capacitor conductor () and the substrate () therebetween, and through the series inductor ().

Multi-frequency antenna

A miniature variable-beam microwave antenna () comprises antenna conductors (), an EBG conductor (), a variable reactance element (), and an adjusting part (). The EBG conductor () is connected to a grounded part () through the variable reactance element (). The adjusting part () changes the apparent reactance of the EBG conductor () by changing the capacity of the variable reactance element (). As the apparent reactance of the EBG conductor () changes, the directivity of the miniature variable-beam microwave antenna () also changes.

A microwave harmonic processing circuit includes (n&#x2212;1) parallel open ended stubs differing in length, connected in parallel to an output terminal of a serial transmission line at a single point, and having predetermined electrical lengths corresponding to second to higher n-th (n is any integer) harmonics, respectively, the serial transmission line having an input terminal connected to an output terminal of a transistor and having a predetermined electrical length; a first strip conductor connecting the serial transmission line to two parallel open ended stubs of the (n&#x2212;1) parallel open ended stubs at a single connecting point; a second strip conductor connecting the (n&#x2212;3) parallel open ended stubs to each other at a single connecting point; a ground layer disposed between first strip conductor and second strip conductor; and a via electrically connecting a connecting portion of first strip conductor and a connecting portion of second strip conductor.

Microwave harmonic processing circuit

The present invention provides a harmonic processing circuit capable of miniaturizing a circuit, and an amplifier circuit using this harmonic processing circuit. A first impedance adjustment section and a second impedance adjustment section are provided. The first impedance adjustment section is provided with a coupled distributed constant line CT. The coupled distributed constant line CT receive as input the output of an amplification transistor S, and have a length of &#xbc; the wavelength (&#x3bb;) of the fundamental wave at the output of the amplification transistor S. Further, the first impedance adjusting section is configured to adjust input impedance with respect to the even harmonics to one of effectively infinity or zero. The first impedance adjusting section and the second impedance adjustment section are configured to adjust input impedance with respect to the odd harmonics to the other of effectively infinity or zero.

Harmonic processing circuit and amplifying circuit using the same

An amplifier circuit operating at a fundamental angular frequency &#x2022;, includes: a transistor which is represented by an equivalent circuit which includes: an equivalent output current source, a drain-source capacitor as a parallel parasitic capacitor to an output node of the equivalent output current source, and a drain inductor as serial parasitic inductor connected between the equivalent output current source and a drain output node; a harmonic frequency processing circuit which includes an input node connected with the drain output node and an output node; a resonant circuit section provided between the output node of the harmonic frequency processing circuit and a ground node and comprising (2n+1) resonators which have resonance frequencies different from each other; and a load resistance provided in a back stage of the harmonic frequency processing circuit. The resonance frequencies of the (2n+1) resonators are coincident with frequencies of (n+1) poles and n zeros formed between the drain output node and the ground node in the transistor when the output node of the harmonic frequency processing circuit is short-circuited to the ground node.

Amplifier circuit

One of the objects of this invention is to realize an antenna having low reflection loss over an extremely wideband. The antenna of the present invention is provided with a dielectric substrate, a plurality of antenna conductors formed on one surface of the dielectric substrate that are pseudo self-complementary on the surface, and a plurality of feed conductors symmetrical with respect to symmetrical surfaces of the antenna conductors, wherein a gap for a wavelength of 1/10 or less that of the wavelength of a usage frequency in a vacuum is provided at a center of rotational symmetry between the plurality of antenna conductors.

Ultra-wideband antenna and ultrahigh frequency circuit module

There is provided a bandpass filter for a differential signal applicable to a device having a wide passband, being a device for transmitting a signal using a differential signal. Respective linesandand linesandare provide on two surfaces Pand Pat an inner layer of a dielectric body. Each two lines are arranged symmetrically about the same plane of symmetry C, and the length of each line is a quarter wavelength at the center frequency of a used band. Reference numeralsandare input/output ends of the linesand, andandare input output ends of linesand. Opposite ends to the input output ends are open. If a differential signal is input to terminals, a differential output appears at the terminals. This device works as a bandpass filter.

Bandpass filter for differential signal, and multifrequency antenna provided with same

A circuit connected between an output terminal of an amplification transistor and a resistor for dealing with higher harmonics included in an output signal transmitted from the amplification transistor, includes (a) a first transmission line having an input terminal electrically connected to the output terminal of the amplification transistor, and having a length of &lgr;/4 wherein &lgr; indicates a wavelength of a fundamental harmonic, (b) a first group of transmission lines, including N transmission lines electrically connected in parallel with one another to an output terminal of the first transmission line, wherein N is an integer equal to or greater than 1, each of the N transmission lines having a length L defined by the following equation: L&equals;&lgr;/4(1&plus;M) (M&equals;1, 2, 3, - - -, N) each of the N transmission lines having an open end, and (c) a second group of transmission lines, including N transmission lines electrically connected in parallel with one another to an output terminal of the first transmission line, each of the N transmission lines having a length Lh defined by the following equation: Lh&plus;L&equals;&lgr;/2, each of the N transmission lines having an open end.

Circuit for dealing with higher harmonics and circuit for amplifying power efficiency

A high-temperature superconductor (HTS) thin film device such as a patch antenna or a microstrip line is produced by using a substrate of a low-permittivity material such as polytetrafluoroethylene in which fine particles of glass fiber are dispersed. Initially a HTS film is deposited on a conventional MgO or SrTiO.sub.3 substrate by sputtering or laser ablation. The low-permittivity substrate is bonded to the HTS film on the oxide substrate with an adhesive, and then the oxide substrate is removed by grinding or abrasion. After that the HTS film on the low-permittivity substrate is patterned. Since the low-permittivity substrate is small in the degree of wavelength shortening, current density in the HTS film reduces and therefore power loss of the device decreases.

Growing community of inventors

Chofu, Japan

Kazuhiko Honjo