Abstract: Provided is a waveguide connection structure 1 in which two waveguides 10 and 20 respectively formed with waveguide paths 11 and 21 face each other, in which a choke groove 25 having a depth corresponding to a leakage prevention target frequency is provided, at the end face 20a of the waveguide 20, in a band-shaped region whose center is a center of the waveguide path 21, and which is bounded by an inner ellipse and an outer ellipse, the minor radius of the outer ellipse is longer than the minor radius of the inner ellipse by a length corresponding, and the choke groove 25 includes two groove portions 25a and 25b that are in contact with the inner ellipse and the outer ellipse and are located on the longer side of the rectangle, in the band-shaped region.

Abstract: A distance between a center of a first probe antenna and a center of a second probe antenna in a measurement plane is longer than a distance between the center of the first probe antenna and a center of a third probe antenna in the measurement plane by a distance between two measurement positions adjacent to each other in a horizontal direction. A distance between a center of a fourth probe antenna and a center of a fifth probe antenna in the measurement plane is longer than a distance between the center of the fourth probe antenna and a center of a sixth probe antenna in the measurement plane by a distance between two measurement positions adjacent to each other in a vertical direction.

Abstract: The system includes a plurality of probe antennas that receive radio signals at a plurality of measurement positions located within a measurement plane in a near field region of an antenna to be measured, a probe scanning mechanism that moves the respective probe antennas to a plurality of measurement positions while maintaining relative positions of the plurality of probe antennas, an amplitude and phase difference measurement unit that measures a phase difference between the radio signals and measures amplitudes of the radio signals, every time the respective probe antennas are moved to the measurement positions, and a phase calculation unit that calculates a phase of the radio signal at each measurement position from the phase difference measured by the amplitude and phase difference measurement unit.

Abstract: The system includes a plurality of probe antennas that receive radio signals at a plurality of measurement positions located within a measurement plane in a near field region of an antenna to be measured, a probe scanning mechanism that moves the respective probe antennas to a plurality of measurement positions while maintaining relative positions of the plurality of probe antennas, an amplitude and phase difference measurement unit that measures a phase difference between the radio signals and measures amplitudes of the radio signals, every time the respective probe antennas are moved to the measurement positions, and a phase calculation unit that calculates a phase of the radio signal at each measurement position from the phase difference measured by the amplitude and phase difference measurement unit.

Abstract: Provided is a technique capable of accurately calculating the radiation power of an object to be measured using a spheroidal coupler even when there is a non-negligible loss in a measurement system. A phase rotating unit including a variable phase shifter, a two-branch circuit, and a reflective element that is connected to one of the branched outputs of the two-branch circuit is inserted between a receiving antenna and a power measuring device. The maximum value and the minimum value of power measured by a power measuring device when the variable phase shifter changes a phase are calculated. An output reflection coefficient of a coupler is calculated from the ratio of the maximum value to the minimum value, and an input reflection coefficient of an object to be measured which is approximate to the output reflection coefficient is estimated. In addition, an input reflection coefficient of a reference antenna which is used instead of the object to be measured is estimated in the same way.

Abstract: Provided is a technique capable of accurately calculating the radiation power of an object to be measured using a spheroidal coupler even when there is a non-negligible loss in a measurement system. A phase rotating unit including a variable phase shifter, a two-branch circuit, and a reflective element that is connected to one of the branched outputs of the two-branch circuit is inserted between a receiving antenna and a power measuring device. The maximum value and the minimum value of power measured by a power measuring device when the variable phase shifter changes a phase are calculated. An output reflection coefficient of a coupler is calculated from the ratio of the maximum value to the minimum value, and an input reflection coefficient of an object to be measured which is approximate to the output reflection coefficient is estimated. In addition, an input reflection coefficient of a reference antenna which is used instead of the object to be measured is estimated in the same way.

Abstract: A tunable laser source apparatus including an external cavity has a semiconductor laser and a wavelength selector. The semiconductor laser includes a reflection surface, a surface with an anti-reflection film and an active layer. The selector selects from laser light emitted from the laser through the surface with the anti-reflection film and feeding laser light of a desired wavelength back to the laser through the surface with the anti-reflection film. The semiconductor laser has a window region formed between a tip portion of the active layer extending toward the surface with the anti-reflection film and the surface with the anti-reflection film, the window region allowing the laser light of the desired wavelength fed back from the selector to be coupling thereon, while dilating the beam size of a portion of the laser light which is reflected from the surface with the anti-reflection film and reach the tip portion film.

Abstract: A tunable laser source apparatus including an external cavity has a semiconductor laser and a wavelength selector. The semiconductor laser includes a reflection surface, a surface with an anti-reflection film and an active layer. The selector selects from laser light emitted from the laser through the surface with the anti-reflection film and feeding laser light of a desired wavelength back to the laser through the surface with the anti-reflection film. The semiconductor laser has a window region formed between a tip portion of the active layer extending toward the surface with the anti-reflection film and the surface with the anti-reflection film, the window region allowing the laser light of the desired wavelength fed back from the selector to be coupling thereon, while dilating the beam size of a portion of the laser light which is reflected from the surface with the anti-reflection film and reach the tip portion film.

Abstract: A laser light source apparatus includes a compound cavity and an optical gain medium. The compound cavity includes first, second, and third optical reflection members disposed along the optical axis. The first optical reflection member has a light wavelength selectivity. At least one of the first to third optical reflection members can change its own position on an optical axis in relation to the other reflection members. Two of the first to third optical reflection members are provided opposite to each other with the optical gain medium inserted therebetween, thereby forming a laser light source. The other one optical reflection member is provided so as to form a light path for feeding laser light emitted from the laser light source back to the laser light source.

Abstract: A tunable laser source apparatus includes an external cavity. The external cavity includes a semiconductor laser and a diffraction section. At least one laser output end facet of the semiconductor laser is covered with an AR coating. The diffraction section includes a first reflector and a diffraction grating, and has wavelength selectivity with which light emerging from the end facet of the semiconductor laser which is covered with the AR coating is received, and light having a predetermined wavelength is selected and reflected toward the semiconductor laser. The semiconductor laser further includes an angle detection section and a control section. The angle detection section detects the angle defined by the optical path of the light emerging from the semiconductor laser and the optical path of the diffracted light reflected by the diffraction section.