National Institute of Information and Communications Technology, Incorporated

Sharp Kabushiki Kaisha Corporation

Oki Electric Industry Co., Ltd.

Communications Research Laboratory, Independent Administrative Institution

Kiyoshi Hamaguchi

Yozo Shoji

Hiroyo Ogawa

Hiroyuki Tsuji

Eiji Suematsu

Hok Huor Ou

Seiji Nishi

A low-cost, compact circular waveguide array antenna which improves an antenna reflection loss characteristic and enables an improvement in radiation characteristics, particularly radiation gain. The circular waveguide array antenna includes feeding portions which feed electromagnetic waves to one ends of circular waveguides and radiation apertures which radiate the electromagnetic waves at the opposite ends. Each circular waveguide includes a conical horn, with a diameter of a feeding side aperture at the feeding portion end being a, a diameter of the radiation aperture being d, which is larger than the diameter a of the feeding side aperture, and an opening angle being 2&#x3b1;. If a wavelength of a central frequency of an employed frequency band is &#x3bb;, then a value of &#x3b1;, which is half of the opening angle, is set between 0.8&#xd7;Arcsin(0.1349114/(d/&#x3bb;)) and 1.2&#xd7;Arcsin(0.1349114/(d/&#x3bb;)).

Circular waveguide antenna and circular waveguide array antenna

The present invention provides a radio communication device, a transmitter and a receiver capable of handling a plurality of signal waves. A radio communication device has a millimeter-wave transmitter () and a millimeter-wave receiver (). Millimeter-wave transmitter () includes a multiplexing circuit (), a millimeter-wave up-converter () and an antenna (), and the millimeter-receiver includes an antenna (), a millimeter-wave down-converter () and an output processing circuit (). The signal waves dedicated to the user are modulated by a modulation circuit (to) so as to be allocated between the ground broadcast waves and satellite broadcast waves. The frequencies are multiplexed in an intermediate frequency band, after that, the multiplexed frequencies are converted into a millimeter-wave band and the resultant is transmitted. On the reception side, the multiplexed waves are down-converted, separated to signal waves and demodulated.

Radio communication apparatus, transmitter apparatus and receiver apparatus

A receiver receives an RF-band modulated signal transmitted from a transmitter, as well as an un-modulated carrier also transmitted from the transmitter and having a phase noise characteristic coherent with that of the modulated signal, and a product of the two components is generated to thereby restore an IF-band transmission source signal. In the receiver, a small planar antenna having a broad beam characteristic such as a single-element patch antenna is combined with an amplifier and a mixer circuit, which are formed on a micro planar circuit by an MMIC technique, so as to form a unit receiving circuit. A plurality of such unit receiving circuits are disposed on the receiver at intervals smaller than a wavelength corresponding to an IF band, and detection outputs from the unit receiving circuits are power-mixed. Thus, the receiver serves as a high-gain antenna having a detection function, and can realize a broad beam radiation characteristic comparable to that of a single-element antenna. The composed IF-band composite output is demodulated in an IF-band demodulation circuit. The present invention enables construction of a low-cost radio communication system, transmission of high-quality signals, and production of a wide beam antenna which has a high gain and which is convenient for use.

Millimeter-wave-band radio communication method in which both a modulated signal and an unmodulated carrier are transmitted to a system with a receiver having plural receiving circuits

A reference local oscillation signal transmission stationradiates a reference local oscillation signal to a service zone. A portion of the signal received by each radio slave station terminalis branched and fed to an injection locked oscillator. As a result, a local oscillation signal which is synchronized with the reference local oscillation signal is obtained. In the slave station terminal, the thus-obtained local oscillation signal is fed to a transmission frequency converter (mixer)and a reception frequency converter (mixer). An IF band transmission modulated signal is fed to the mixerfor frequency conversion to a radio frequency band, and the thus-obtained radio-frequency modulated signal is transmitted. Meanwhile, a received radio-frequency modulated signal is fed to the mixerfor down conversion, and the thus-obtained signal is fed to an IF band demodulatorso as to restore an information signal. The present invention not only solves the problem of deterioration of signal quality stemming from phase noise and frequency offset generated in a millimeter wave band oscillator, but also improves the efficiency of frequency use.

Radio communication method and system for performing communication among a plurality of radio communication terminals

A transmittertransmits from a transmission antennaa mixture signal containing a radio-frequency (RF)-band modulated signal, and a portion of power of a local oscillation signal used for frequency conversion. Meanwhile, a receiverdetects the transmitted signal by means of a reception antenna-detection section. In the reception antenna-detection section, a plurality of base unit reception circuitsare disposed. Each base unit reception circuitincludes a planar printed antennasuch as a patch antenna, an amplifier circuitformed on a very small planar circuit by means of an MMIC technique, and a mixer circuitserving as a square-law detector. Respective outputs of the base unit reception circuitsare power-mixed and fed to the IF signal demodulation section. The IF signal demodulation sectiondemodulate reception data. This configuration enables realization of a reception antenna which occupies a very small space, has a detection function and a high gain, and has a wide beam characteristic comparable to that of a single-element antenna.

Radio communicate method and system

This invention includes a wireless transmitter comprising an IF-signal generator that modulates input signals into those of an intermediate frequency band, signal distributors that distribute signals from the IF-signal generator, and a plurality of signal-transmission units that convert the signals distributed by the signal distributors into those of a radio frequency band, and then transmit the converted radio signals. The invention also includes a wireless receiver that receives the radio-frequency-band modulated signals and restores the signals of the intermediate frequency band. In this way, effective diversity is realized and signal interruptions are prevented. In addition, a handy, low-cost wireless communications system is provided.

Wireless communications system, wireless transmitter, and wireless receiver

Only a first radio station is equipped with a local oscillation signal source. A signal transmitted to a second radio station includes local oscilaation signal components used to up-convert a modulated intermediate frequency band signal in addition to intermediate frequency band signal components. The second radio station that receives the signal from the first radio station extracts and regenerate the local oscillation signal used at the first radio station using a local oscillation signal regenerator. The extracted and regenerated local oscillation signal is used to down-convert modulated radio signal components to the intermediate frequency band and simultaneously up-convert to the radio frequency band the modulated intermediate frequency band signal to be transmitted to the first radio station.

Two-way radio communication system and two-way radio communication method

In a radio communication apparatus and method, on the transmitting side, an input signal is modulated in an intermediate frequency band to produce a modulated intermediate frequency band signal, a local oscillation signal is used to up-convert the modulated intermediate frequency band signal to a modulated radio frequency band signal, and the local oscillation signal and the modulated radio frequency band signal are simultaneously transmitted as a radio signal, and, on the receiving side, the radio signal from the transmitter is received, the received signal is down-converted by multiplying the local oscillation signal component and the modulated radio frequency band signal component contained in the received signal to generate a multiplication component and thereby produce a modulated intermediate frequency band signal, and the modulated intermediate frequency band signal is demodulated.

Growing community of inventors

Tokyo, Japan

Kiyoshi Hamaguchi