Mitsubishi Denki Kabushiki Kaisha

Other

Nippon Telegraph and Telephone Corporation

National Space Development Agency of Japan

Nippon Telegraph

Telephone Corporation

Mitsubishi Denki Kabushiki Denki

Takashi Katagi

Nobutake Orime

Makoto Matsunaga

Shuji Urasaki

Tetsuo Haruyama

Yoshihiko Konishi

Hiroyuki Ohmine

Katsuhiko Aoki

Yuji Kobayashi

Moriyasu Miyazaki

Isamu Chiba

Koichi Tsunekawa

Masato Inoue

Shigeru Makino

Hideki Asao

Kenichi Kagoshima

Seiji Mano

Yoshiyuki Chatani

Osami Ishida

Shinichi Betsudan

Kazushi Nishizawa

Takashi Ebisui

Shigeru Sato

Toshio Nishimura

Hirokazu Tanaka

Shusou Wadaka

Yoshiaki Tsuda

Toshihiko Aoki

Jun Saito

Masataka Ohtsuka

Hiroaki Miyashita

Hiroyuki Deguchi

Fumio Takeda

Minoru Tajima

Tadashi Takano

Tsutomu Hashimoto

Yonehiko Sunahara

Koryo Miura

Yasuhiko Nishioka

Toshio Masujima

Shigeo Udagawa

Kuniaki Shiramatsu

Susumu Hishinuma

Shin-ichi Satoh

Takayoshi Huruno

Ryuji Ishii

Koushi Ogiso

Toneo Kawanishi

Yasuo Tamai

Hiroyuki Aoki

Takayoshi Furuno

Kazuhito Miyashita

Yasuhiro Itabashi

Akio Iso

Shin-ichi Sato

Yoshihiro Takeichi

Shunichiro Kawabata

A two-frequency antenna includes feeders and , inner radiation elements and connected to the feeders, outer radiation elements and , and inductors and that are formed in gaps and between the inner radiation elements and the outer radiation elements to connect the two radiation elements, which are printed on the first surface and on the second surface of the dielectric board , respectively.

Two-frequency antenna, multiple-frequency antenna, two- or multiple-frequency antenna array

An array antenna includes systematically arranged linear antennas belonging to two or more groups consisting of linear antennas operating at respective frequencies, so that the array antenna can operate at two or more operating frequencies. Each linear antenna that operates at a relatively low frequency includes antenna elements having cranks formed thereon.

Multi-frequency array antenna

A mobile satellite communication system including an artificial satellite which is situated in a satellite orbit and develops an active phased array antenna so as to accomplish a line to a terrestrial station using a portable terminal in a specific area. As a result, a service that satisfies a demand for communication in the specific area can be realized.

Mobile satellite communication system

Herein is revealed a helical antenna apparatus wherein the direction of beam radiation hardly changes even if the frequency in use changes. Two helical antennas which are wound with two conductive wires spirally, respectively, at equal intervals with a specified pitch .alpha. in the form of a cylinder are disposed along the length of the helical antennas so that the axes thereof substantially coincide with each other. By determining the lengths of the feeders of the respective helical antennas appropriately in order to set the phase of supplied power, it is possible to form the beam of signals radiated into space in the shape of conical beam having a directivity oriented obliquely upward. Additionally, it is possible to obtain the conical beam in which the direction of beam radiation does not change even if the frequency in use is changed.

Antenna apparatus

There is provided a small-sized and simplified horizontally polarized antenna apparatus which forms an omnidirectional pattern in the horizontal plane. The radiation field in the horizontal plane becomes continuous and a horizontally polarized omnidirectional radiation pattern can be obtained in the horizontal plane by forming radiation slots at opposing positions on a grounded hollow body and exciting the slots out of phase.

Omnidirectional slot antenna

In order to perform feeding to an inverted F antenna having a plate conductor of an approximately rectangular shape for forming a radiation conductor and a ground conductor arranged in parallel with the plate conductor, a strip conductor plate connected to a feeder line is provided on the ground conductor via a dielectric substrate. Hence, the feeding from the feeder line to the inverted F antenna 37 is performed by an electric field coupling of the plate conductor and the strip conductor plate. The inverted F antenna and a resonator are integrated by coupling means to carry out an impedance matching, and the inverted F antenna and the resonator 62 constitute a band pass filter.

Antenna device having a band pass filter

An antenna apparatus comprises a dielectric substrate, an earth conductor mounted on one surface of the substrate and forming a microstrip transmission line, an upper conductor mounted on the other surface of the substrate and forming a microstrip transmission line, an antenna element formed integrally with the microstrip transmission lines, and a delayed wave opening situated in the earth conductor in confronting relationship with the upper conductor.

Antenna apparatus and antenna system

In order to perform feeding to an inverted F antenna having a plate conductor of an approximately rectangular shape for forming a radiation conductor and a ground conductor arranged in parallel with the place conductor, a strip conductor plate connected to a feeder line is provided on the ground conductor via a dielectric substrate. Hence, the feeding from the feeder line to the inverted F antenna 37 is performed by an electric field coupling of the plate conductor and the strip conductor plate. The inverted F antenna and a resonator are integrated by coupling means to carry out an impedance matching, and the inverted F antenna and the resonator 62 constitute a band pass filter.

Inverted F antenna with non-contact feeding

An array antenna mounted on a spacecraft in its stowed state. After the spacecraft is launched in a predetermined position or on a predetermined orbit, the array antenna is extended to a flat plate form or a curved surface form. The array antenna has a structure that a plurality of subarrays are connected by plate springs or the like. The array antenna is extended in a kite form by using cables for connecting a spacecraft body and the subarrays or is extended by using an extension pole mounted on the spacecraft body. Each subarray includes a variable phase shifter to switch a shape and a direction of a directivity beam. A feeder line, a power supply line, a control signal line and the like connect the spacecraft body and each subarray.

Array antenna mounted on spacecrafts

A positioner supports an antenna at an optional rotating angle and the mirror surface of the antenna at different rotating angles is measured. A computer expands the measured value into series using polar coordinates system associated with the measuring system, whereby the intrinsic deformation of the mirror surface under the zero-gravity condition and the deformation due to gravity are separately measured.

Antenna mirror-surface measuring system

A multi-layer array antenna having high frequency band microstrip antennas formed on a surface of a first dielectric substrate, comb-shaped low frequency band microstrip antennas formed on a surface of a second dielectric substrate which is disposed on the first dielectric substrate, and through-holes for supplying microwave power to the comb-shaped low frequency band microstrip antennas through the first and the second dielectric substrates.

Multi-layer array antenna

An antenna system for transmitting radio waves in the same direction as the direction of arrival of incoming radio waves. The arrival direction is detected by a fast Fourier transform processor. The transmitting direction is adjusted by phase-shifting radio waves from a feeder on the basis of the detected arrival direction. Further, signals in the system are transmitted through optical fibers in order to decrease the processing time.

Antenna system

A method of and an apparatus for measuring the null angle in the difference vs. sum pattern and in the difference pattern of a monopulse antenna. The null angle of the monopulse antenna in the radiation pattern is acquired by transmitting an RF signal from a plurality of antenna elements to the monopulse antenna, acquiring the sum signal and difference signals in the directions of the respective antenna elements and acquiring the null angle in accordance with the sum and difference signals. The apparatus comprises a rotator for changing the direction of the monopulse antenna and a transmitting antenna facing the monopulse antenna for transmitting a test signal to the monopulse antenna.

Method of measuring the null angle of a monopulse antenna and apparatus

An antenna system in which main and subreflectors are arranged in such a manner to suppress the generation of a cross-polarized component due to the antisymmetry of the reflectors. Thereby, the antenna system can provide a preferable cross-polarization characteristics even in the working frequency bands.

A phased array antenna includes a plurality of first antenna elements and a plurality of phase shifters respectively connected to the first antenna elements. An amplitude and a phase of each of the antenna elements are determined by a method of opposing a pick-up antenna at a distance from the phased array antenna to measure a composite power of the phased array antenna while changing phases of the phase shifters for determining the ratio of the maximum power to the minimum power, and the phase value for the maximum power, from which the amplitude and phase are computed. A second antenna element is incorporated in the phased array antenna as a pick-up antenna to measure with mutual coupling an amplitude and a phase of each antenna element by the method and to determine differences in amplitude and phase between the opposed pick-up antenna and the second antenna element so that an amplitude and a phase subsequently measured with the second antenna element are corrected with the differences in amplitude and phase to determine an amplitude and a phase of each antenna element.

Growing community of inventors

Kanagawa, Japan

Takashi Katagi