Abstract: Disclosed is an image capturing apparatus comprising a primary mirror 1 that has a surface which is a section of a surface cut out from a paraboloid with a single focus; a secondary mirror 2 that has a surface which is a section of a surface cut out from a hyperboloid with two foci; and a photodetector 3 which converts the light signal coming from the secondary mirror 2 into an electric signal. The secondary mirror 2 is placed in a position where one of its foci and the focus of the primary mirror 1 match with each other. The photodetector 3 is placed near the other focus of the secondary mirror 2. By using two mirrors, the light from the object is led to the photodetector 3 without being shaded.

Abstract: For the purpose of obtaining a mechanical drive reflecting mirror antenna device which is downsized and low in attitude, enables wide-angle scanning, and is high in performance, there are provided a main reflection mirror 1, a sub-reflection mirror 2, a primary radiator 3, a first circular waveguide 4 which is connected to the primary radiator and has a plurality of bend portions, a first circular waveguide rotary joint 5 which is connected to the first circular waveguide, a second circular waveguide 7 which is connected to the first circular waveguide rotary joint and has a plurality of bend portions, and a second circular waveguide rotary joint 8 which is connected to the second circular waveguide and is different in a direction of a rotary axis from the first circular waveguide rotary joint by substantially 90 degrees.

Abstract: There are disposed four antenna elements which are arranged circumferentially at regular intervals, and four 90-degree hybrids each having four terminals, two 90-degree hybrids which are arranged in parallel are connected in two stages, only one of the output terminals of an upstream 90-degree hybrid and only one of the input terminal of a downstream 90-degree hybrid cross each other and are connected to each other, and the four output terminals of the two downstream 90-degree hybrids and the four antenna elements are connected to each other; the passing phase between the terminals that cross each other within the respective 90-degree hybrids is set to 0 degree, and the passing phase between the terminals that are in parallel within the respective 90-degree hybrids is set to 90 degrees. As a result, the structure of the feed circuit can be simplified, and plural kinds of beams can be formed.

Abstract: In order to provide a reflector antenna apparatus which can be installed within a small space, which has adequate practicality, and which can perform scanning by pivoting about two axes which are perpendicular to each other, in a reflector antenna apparatus having a Cassegrain reflector and a rotating mechanism which rotates the reflector about an azimuth axis and an elevation axis, a reflector with a substantially rectangular aperture has its elevation axis passing through substantially the central portion of the height dimension of the reflector, and reflector surface adjustment is carried out such that substantially all of the electromagnetic waves which are supplied are received and reflected, whereby the antenna height does not become large when the reflector rotates about the elevation axis. The reflector may be an array of a plurality of reflector elements.

Abstract: A directivity control of an adaptive antenna is performed for an antenna of a base station when a signal is received in the antenna of the base station, and the directivity control of the adaptive antenna is performed for an antenna of a mobile station when a signal is received in the antenna of the mobile station. Therefore, even though an antenna of a second mobile station functions as an interference wave source, the reception of an interference wave from the interference wave source can be prevented in both the antenna of the base station and the antenna of the mobile station, and a communication quality in both the base station and the mobile station can be maintained in the communication between the base station and the mobile station.

Abstract: A plurality of concentric circle array antennas each having a different radius are disposed on an identical plane, and a plurality of element antennas are arranged circumferentially in each of the concentric circle array antennas. The plurality of concentric circle array antennas are arranged at regular intervals d in most part thereof, and the concentric circle array antennas corresponding to a remaining part of the plurality of concentric circle array antennas are arranged at intervals d±0.4 to 0.6d. The radii of the part of plural concentric circles change by ±(0.4 to 0.6)d, so that it is possible to reduce a wide-angle side lobe.

Abstract: There are disposed four antenna elements which are arranged circumferentially at regular intervals, and four 90-degree hybrids each having four terminals, two 90-degree hybrids which are arranged in parallel are connected in two stages, only one of the output terminals of an upstream 90-degree hybrid and only one of the input terminal of a downstream 90-degree hybrid cross each other and are connected to each other, and the four output terminals of the two downstream 90-degree hybrids and the four antenna elements are connected to each other; the passing phase between the terminals that cross each other within the respective 90-degree hybrids is set to 0 degree, and the passing phase between the terminals that are in parallel within the respective 90-degree hybrids is set to 90 degrees. As a result, the structure of the feed circuit can be simplified, and plural kinds of beams can be formed.

Abstract: In order to provide a reflector antenna apparatus which can be installed within a small space, which has adequate practicality, and which can perform scanning by pivoting about two axes which are perpendicular to each other, in a reflector antenna apparatus having a Cassegrain reflector and a rotating mechanism which rotates the reflector about an azimuth axis and an elevation axis, a reflector with a substantially rectangular aperture has its elevation axis passing through substantially the central portion of the height dimension of the reflector, and reflector surface adjustment is carried out such that substantially all of the electromagnetic waves which are supplied are received and reflected, whereby the antenna height does not become large when the reflector rotates about the elevation axis. The reflector may be an array of a plurality of reflector elements.

Abstract: For the purpose of obtaining a mechanical drive reflecting mirror antenna device which is downsized and low in attitude, enables wide-angle scanning, and is high in performance, there are provided a main reflection mirror 1, a sub-reflection mirror 2, a primary radiator 3, a first circular waveguide 4 which is connected to the primary radiator and has a plurality of bend portions, a first circular waveguide rotary joint 5 which is connected to the first circular waveguide, a second circular waveguide 7 which is connected to the first circular waveguide rotary joint and has a plurality of bend portions, and a second circular waveguide rotary joint 8 which is connected to the second circular waveguide and is different in a direction of a rotary axis from the first circular waveguide rotary joint by substantially 90 degrees.

Abstract: A plurality of concentric circle array antennas each having a different radius are disposed on an identical plane, and a plurality of element antennas are arranged circumferentially in each of the concentric circle array antennas. The plurality of concentric circle array antennas are arranged at regular intervals d in most part thereof, and the concentric circle array antennas corresponding to a remaining part of the plurality of concentric circle array antennas are arranged at intervals d±0.4 to 0.6 d.

Abstract: A directivity control of an adaptive antenna is performed for an antenna of a base station when a signal is received in the antenna of the base station, and the directivity control of the adaptive antenna is performed for an antenna of a mobile station when a signal is received in the antenna of the mobile station. Therefore, even though an antenna of a second mobile station functions as an interference wave source, the reception of an interference wave from the interference wave source can be prevented in both the antenna of the base station and the antenna of the mobile station, and a communication quality in both the base station and the mobile station can be maintained in the communication between the base station and the mobile station.

Abstract: An antenna mirror surface measuring/adjusting apparatus has a plane mirror larger than an aperture surface of said principal reflection mirror and set in parallel with the aperture surface, an actuator for driving a group of mirror surface panels of the principal reflection mirror, and a receiving electric field arithmetic processor for measuring, each time the actuator shifts a position of the mirror surface panel from an initial state of the mirror surface panel of the principal reflection mirror, radio wave signals of radio waves radiated by a transmitter/receiver and reflected back from the plane mirror, obtaining an aperture surface phase distribution in an initial state of the principal reflection mirror by executing an arithmetic process on these measured signals, then gaining configurations of the mirror surface on the basis of the aperture surface phase distribution, and adjusting the mirror surface by the actuator in accordance with the obtained mirror surface configurations.

Abstract: A composite antenna apparatus comprising a balun connected to an inner conductor at the upper end of a coaxial line 11, one end of a helical element formed by a pair of wire conductors is connected to the balun, the other end is wound symmetrically around the coaxial line using the the coaxial line as a center so as to face the balun and is connected to the outer conductor 13 at the lower end of the coaxial line. The provision of an outer conductor connecting terminal connected to the outer conductor and an inner conductor connecting terminal connected to the inner conductor at the lower end of the coaxial line, allows the formation, on the same axis, of a helical antenna fed by the coaxial line via the helical element and a monopole antenna formed by the outer conductor of the coaxial line. Thereby equivalent gain in the horizontal plane and a reduction in the occupied volume is achieved.

Abstract: An antenna apparatus for a portable telephone which is capable of having a better gain characteristic and also capable of achieving a better circularly polarized characteristic over a wide range is provided.

Abstract: 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.

Abstract: A non-driven first linear element is disposed in the vicinity of an inverted-F second linear antenna element. The driven second linear element is disposed over a conductive plate having a flat shape, in such a manner as to be substantially parallel to the inverted-F antenna. The non-driven element has a short-circuited end of the inverted-F antenna, and has substantially the same resonant frequency as that of the inverted-F antenna.

Abstract: 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.

Abstract: A frequency synthesizer, including a direct digital synthesizer (DDS) for providing wave amplitude data as a standard signal source, and a phase lock loop for comparing a branched synthesizer frequency with the standard signal source at a phase comparator. A frequency converter converts the output frequency of the DDS to a higher frequency and provides the resultant higher frequency to the phase comparator in the phase loop. A small loop dividing ratio is obtained by converting the low frequency of the DDS to a higher frequency. A spurious of the synthesizer output signal is reduced and provides a low power consumption apparatus.

Abstract: In an amplifying feedback-type FET semiconductor element for use as a wide-band microwave amplifier in telecommunications system such as a radar, a monolithic IC feedback circuit is located between at least two parallel FET cells of an FET semiconductor element and also between gate and drain lead electrodes of the FET semiconductor element. The feedback circuit includes at least two connecting lines and at least one passive element and is connected to the two lead electrodes. With this arrangement, it is possible to reduce the total length of said connecting lines to a minimum, thus guaranteeing a frequency characteristic showing a flat gain over a wide band.

Abstract: A low-distortion radio-frequency amplifying apparatus is equipped with a distortion compensating circuit for generating a distortion signal which cancels a distortion generated during radio-frequency amplification. The apparatus detects a signal corresponding to an envelope power of the output or input of an amplifier, varies a distortion compensating characteristic according to the power value, and compensates a distortion over a wide dynamic range. The apparatus includes a detector for detecting an envelope detection signal of the amplifier, and a controller for compensating the distortion compensating characteristic according to the detected signal.