Abstract: A small-sized cylindrical waveguide having a low reflection characteristic is disclosed. An inner bent portion connects cavities of first and second waveguide portions in a range of not larger than one-fourth of the diameter of the cavities on each of an extension line of an innermost wall portion in the cavity of the first waveguide portion and an extension line of an innermost wall portion in the cavity of the second waveguide portion, from an intersecting point of both extension lines.

Abstract: A dielectric plate is fixed inside a first waveguide, the inside of which is hollow, having a square opening at one end thereof, the dielectric plate is orthogonal to two parallel sides of the opening, a second waveguide having a square cross-section is connected to the other end of the first waveguide, and the dielectric plate is tilted by substantially 45° with respect to a pair of opposing internal wall surfaces of the second waveguide.

Abstract: The present invention provides a primary radiator capable of achieving both loss reflection and low loss. A watertight cap made of a dielectric material having a relatively high dielectric constant is attached to an open end of a horn part continuing from a waveguide, a dielectric member made of a dielectric material having a lower dielectric loss than the watertight cap is disposed within the waveguide, and a projecting part integrally formed at an end of the dielectric member is extended to the inside of the horn part, whereby an end face of the projecting part is made to face the back of the watertight cap at a fixed interval.

Abstract: A dielectric plate, serving as a 90-degree phase device, is disposed inside a waveguide. A phase-converting portion of uniform thickness is formed at the central portion of the dielectric plate, and stepped portions, serving as impedance converting portions, are formed at both longitudinal end portions of the phase converting portion by causing protrusions to be protrude from both of the longitudinal end portions. The protrusions are disposed on orthogonal axes extending in widthwise and thickness directions of the dielectric plate. The protruding amount of each of the protrusions from end surfaces of the phase converting portion is approximately ¼ of a wavelength &lgr;g inside the waveguide. The end surfaces of the phase converting portion and corresponding end surfaces of the protrusions form reflecting surfaces that are orthogonal to the direction of propagation of an electrical wave.

Abstract: The primary radiator comprises a circular waveguide having a cone-shaped horn portion at one end and an enclosing surface at the other end, and a first and second probes inserted into the waveguide through a wall thereof. A plurality of cutout portions are formed at an open end of the horn portion. Two or more pairs of cutout portions are disposed symmetrically with respect to an axis of the waveguide and a depth of each cutout portion is adjusted to be about one quarter of the wavelength of the radio wave &lgr;0 transmitted through the air. With such a configuration, the phase reversal of surface currents flowing through the cutout portions and an adjacent projecting portion (a portion without cutout portions) take place, and a side lobe of a radiation pattern can be reduced considerably.

Abstract: A primary radiator includes a waveguide holding a dielectric feeder on which a radiation part, an impedance-conversion part, and a phase-conversion part are integrally formed. The radiator part widens from the aperture of the waveguide, and the phase-conversion part intersects a probe at an angle of substantially 45 degrees. Also, on the impedance-conversion part, a pair of curved surfaces are formed converging in the direction from the radiator part to the phase-conversion part, the impedance-conversion part has a cross-sectional shape which includes an approximately quadratic curve, and the thickness of the dielectric feeder converges such that the thickness gradually decreases in the direction from the radiator part to the phase-conversion part.

Abstract: A dielectric feeder has a holding portion inserted into the interior of a waveguide and a horn-shaped radiating portion having different radiation angles in major- and minor-axis directions. A plurality of annular grooves each having a depth corresponding to about a quarter wavelength of a radio wavelength &lgr;0 is formed in an end face of the radiating portion. An outer peripheral surface of the holding portion is cut out at circumferentially opposed positions axially in parallel with each other to form a pair of flat surfaces. Both flat surfaces are positioned in the major axis directions of the radiating portion and are thereby allowed to function as a phase compensating portion for compensating a propagative phase difference induced in the radiating portion. Further, there is formed a stepped hole comprising two recesses which are contiguous to each other from an end face of the holding portion toward the interior of the holding portion.

Abstract: In a primary radiator, a dielectric plate is fixed to the interior of a hollow first waveguide having, at one end, an opening shaped like a regular square, and is substantially orthogonal to two parallel sides of the opening. A second waveguide of rectangular cross section is coaxially connected to the other end of the first waveguide. A pair of probes are disposed at an angle of approximately 45° with respect to the dielectric plate so as to protrude from flat inner wall surfaces of the second waveguide toward the center axis.

Abstract: A simply structured converter for satellite communication reception which can contribute to reducing signal losses and to simplifying the assembling work is to be provided. Orthogonal bipolarized signals transmitted from a satellite are branched into two propagation paths within a waveguide, and a horizontally polarized wave is caused to proceed in a first propagation path, while a vertically polarized wave is caused to proceed in a second propagation path. A pair of probes are supported by a circuit substrate fitted to a case, and tips of the probes extend into two waveguides provided in the case. By integrating the waveguide and the case by fixing means such as bolts, the first propagation path and the first waveguide are let to communicate with each other, and so are the second propagation path and the second waveguide.

Abstract: A dielectric plate, serving as a 90-degree phase device, is disposed inside a waveguide. A phase-converting portion of uniform thickness is formed at the central portion of the dielectric plate, and stepped portions, serving as impedance converting portions, are formed at both longitudinal end portions of the phase converting portion by causing protrusions to be protrude from both of the longitudinal end portions. The protrusions are disposed on orthogonal axes extending in widthwise and thickness directions of the dielectric plate. With respect to a width W1 and a thickness T1 of the central portion of the dielectric plate, a width W2 and a thickness T2 of each of the protrusions are such that W2<W1 and T2<T1, respectively. When the protruding amount (height) of each of the protrusions from end surfaces of the phase converting portion is represented by H, H is approximately ¼ of a wavelength &lgr;g inside the waveguide.

Abstract: A dielectric plate is fixed inside a first waveguide, the inside of which is hollow, having a square opening at one end thereof, the dielectric plate is orthogonal to two parallel sides of the opening, a second waveguide having a square cross-section is connected to the other end of the first waveguide, and the dielectric plate is tilted by substantially 45° with respect to a pair of opposing internal wall surfaces of the second waveguide.

Abstract: A primary radiator has a dielectric feeder at an open end of a waveguide in which the total length of the dielectric feeder is reduced. The dielectric feeder includes a holding portion forced into the interior of the open end portion of the wave guide and a radiation portion protruding outwardly from the open end of the wave guide, at least one recess being formed in each end surface of the two portions. The recess includes a stepped hole composed of a large diameter cylindrical hole and a small diameter cylindrical hole connected to the bottom surface thereof, the depth of each cylindrical hole being approximately ¼ of the wavelength &lgr;&egr; of the radio wave propagated through the dielectric feeder.

Abstract: The present invention provides a primary radiator capable of achieving both loss reflection and low loss. A watertight cap made of a dielectric material having a relatively high dielectric constant is attached to an open end of a horn part continuing from a waveguide, a dielectric member made of a dielectric material having a lower dielectric loss than the watertight cap is disposed within the waveguide, and a projecting part integrally formed at an end of the dielectric member is extended to the inside of the horn part, whereby an end face of the projecting part is made to face the back of the watertight cap at a fixed interval.

Abstract: A dielectric feeder has a holding portion inserted into the interior of a waveguide and a horn-shaped radiating portion having different radiation angles in major- and minor-axis directions. A plurality of annular grooves each having a depth corresponding to about a quarter wavelength of a radio wavelength &lgr;0 is formed in an end face of the radiating portion. An outer peripheral surface of the holding portion is cut out at circumferentially opposed positions axially in parallel with each other to form a pair of flat surfaces. Both flat surfaces are positioned in the major axis directions of the radiating portion and are thereby allowed to function as a phase compensating portion for compensating a propagative phase difference induced in the radiating portion. Further, there is formed a stepped hole comprising two recesses which are contiguous to each other from an end face of the holding portion toward the interior of the holding portion.

Abstract: In a primary radiator, a dielectric plate is fixed to the interior of a hollow first waveguide having, at one end, an opening shaped like a regular square, and is substantially orthogonal to two parallel sides of the opening. A second waveguide of rectangular cross section is coaxially connected to the other end of the first waveguide. A pair of probes are disposed at an angle of approximately 45° with respect to the dielectric plate so as to protrude from flat inner wall surfaces of the second waveguide toward the center axis.

Abstract: A feed horn comprises a waveguide having an opening portion of a circular section and a horn portion having an elliptic open end and connected to the waveguide. On an inner slant peripheral surface of the horn portion are formed a plurality of elliptic grooves at radial intervals axially from a front end of the horn portion toward the waveguide, as well as a plurality of axially extending elliptic ridges partitioned by the grooves. Tip ends of the ridges are formed with a difference in height so as to approach the waveguide successively as they are positioned radially centrally. The horn portion has an elliptic tapered portion which expands in a horn shape from one axial end of the horn portion toward a front end of the elliptic open end, namely, the axial front end of the horn portion.

Abstract: A feedhorn of the invention comprises: at least first and second waveguides in positions so as to face each other over a center line, each having an axis parallel to the center line; and first and second horns on extension lines of the axes. The outer ends of the first and second horns have aperture end faces, respectively. Each of the aperture end faces of the first and second horns is tilted toward the center line by a predetermined angle so that the first and second horns are perpendicular to the travel directions of radio waves transmitted from at least two broadcasting satellites orbiting around the earth and reflected by an antenna on the ground.

Abstract: In a satellite broadcasting converter, converting portions project from an inner face portion of a horn section, and therefore, the inner face of a waveguide section, the inner face portion of the horn section, and the converting portions can be formed by using a single mold. This reduces the number of molds, compared with the conventional converter, and thereby achieves a low-cost satellite broadcasting converter.

Abstract: A radiation section of a dielectric feeder protrudes from an opening of a waveguide to improve the efficiency of receiving radio signals. An opening is provided at one end of the waveguide. A dielectric feeder held within the waveguide has a radiation section protruding from the opening. An annular wall having a bottom surrounds the opening of the waveguide. The depth of the annular wall is about ¼ of the wavelength of radio waves, and the width of a bottom surface of the annular wall is about ⅙ to {fraction (1/10)} of the wavelength of the radio waves. Consequently, the phases of a surface current that flows from the opening toward the bottom surface of the annular wall and a surface current which flows from the bottom surface of the annular wall toward the open end are substantially out of phase. As a result, the side lobes of the received radio signals are greatly reduced, and the gain of the main lobe is increased, improving the reception of radio waves transmitted from a satellite.

Abstract: A fifth transmission line is connected between points at each of which a difference between a length from the point to one side of one antenna element in a first transmission line or a second transmission line and a length from the point to one side of the other antenna element is equal to the half of the wavelength. A sixth transmission line is connected between points at each of which a difference between a length from the point to one side of one antenna element in a third transmission line or a fourth transmission line and a length from the point to one side of the other antenna element is equal to the half of the wavelength. A voltage based on a vertically polarized wave is outputted from an intermediate point of the fifth transmission line and a voltage based on a horizontally polarized wave is outputted from an intermediate point of the sixth transmission line.