摘要:
A first oscillator includes: a ring resonator; an oscillation circuit having a negative resistance active circuit coupled to a first point on the ring resonator for oscillating at an oscillation frequency and resonating the resonator; an output terminal, coupled to a second point on the ring resonator where a voltage is substantially zero with respect to the predetermined frequency when the ring resonator resonates, for outputting a resonant frequency signal, wherein even order harmonic components are outputted with the fundamental component suppressed. A second oscillator includes a ring resonator having points A to D equidistantly dividing the ring resonator, first and second oscillation circuits coupled to the points A and B respectively, first and second grounding capacitors having capacitance equivalent to those of the first and second oscillation circuits. Thus, two independent oscillators which do not affect each other are provided with a single resonator. In the first and second oscillators, grounding capacitors, a resonant capacitor may be provided to miniaturize the oscillator. Variable capacitances may be provided to prevent the point from moving with a change in the controlled oscillation frequency. Frequency synthesizers and communication apparatus including the first or second oscillator are also disclosed.
摘要:
A strip-line resonator comprises a first dielectric substrate having a conductive film on one surface thereof for connection to ground and a strip line on the other surface thereof and a second dielectric substrate having one surface thereof making contact with the strip line and a conductive film on the other surface thereof for connection to ground. Fused glass having a low melting point for is applied between the first and second substrates to bond them together. A portion of open-circuit end of the strip line is exposed and formed with slits or gap to facilitate frequency adjustment.
摘要:
A band-stop filter for VHF-UHF band comprises at least three series resonance circuits and at least two transmission lines each connected between the series resonance circuits. One of the transmission lines, which is connected to the input terminal of the band-stop filter, has an electrical length which is shorter or longer than the quarter wavelength of the center frequency of the stop band by more than 20 but less than 50 percent. When a band-stop filter comprises four transmission lines, one of the transmission lines, which is connected to the output terminal of the band-stop filter, has the same length as the transmission line connected to the input terminal. With this arrangement, the band-stop filter exhibits a sharp attenuation characteristic in a frequency range below or above the center frequency. Other transmission lines, which are not directly connected to either the input terminal or the output terminal, may have a length which is shorter or longer than the quarter wavelength by 5 to 20 percent so as to provide a sharper attenuation characteristic.
摘要:
A transmission line resonator includes a half-wavelength stepped-impedance resonator with two ends short-circuited to ground, and a capacitive element with one end connected to a center portion of the stepped-impedance resonator and the other end short-circuited to ground. The stepped-impedance resonator includes a first transmission line, a second transmission line, and a third transmission line. The second transmission line has a second line impedance and a second line length, with one end being connected to one end of the first transmission line and the other end being short-circuited to ground. The third transmission line has the second line impedance and the second line length, with one end being connected to the other end of the first transmission line and the other end being short-circuited to ground. The first line impedance is lowered in comparison with the second line impedance.
摘要:
A transmission line resonator includes a half-wavelength stepped-impedance resonator with two ends short-circuited to ground, and a capacitive element with one end connected to a center portion of the stepped-impedance resonator and the other end short-circuited to ground. The stepped-impedance resonator includes a first transmission line, a second transmission line, and a third transmission line. The second transmission line has a second line impedance and a second line length, with one end being connected to one end of the first transmission line and the other end being short-circuited to ground. The third transmission line has the second line impedance and the second line length, with one end being connected to the other end of the first transmission line and the other end being short-circuited to ground. The first line impedance is lowered in comparison with the second line impedance.
摘要:
A strip-line filter is provided with upper- and lower-stage resonators having the same electromagnetic characteristics. Each of the resonators has a one-wavelength square-shaped strip line and four open-end transmission lines connected to four coupling points A,C,B and D (or E,G,F and H) of each resonator which are spaced 90 degrees in electric length in that order. The square-shaped strip lines have a pair of parallel coupling lines closely placed in parallel to each other to electromagnetically couple the resonators. Therefore, the filter can be manufactured in a small size. A first microwave resonated in each resonator is electromagnetically influenced by two open-end transmission lines connected to two coupling points A and B (or E and F), and a second microwave resonated in each resonator is electromagnetically influenced by two open-end transmission lines connected to two coupling points C and D (or G and H). Therefore, resonance wavelengths of the microwaves can be longer than a line length of each square-shaped strip line. Also, the resonance wavelengths can be adjusted by trimming the transmission lines. Also, because all constitutional elements are made of strip lines, the filter can be made plane.
摘要:
A first bandpass filter comprises: a plurality of resonators and input/output lines formed such that a strip line formed in a substantially straight line is cut in an inclined direction to the straight line to form a plurality of resonators spaced apart by gaps, the resonators being coupled across the gaps. Each of the resonators may be formed in parallelogram. Each of the resonators may be formed in a substantial isosceles triangle. A second bandpass filter comprises: a plurality of resonators and a ground electrode, each of the resonators having an open-end strip line, one end of each of the strip line being connected to the ground electrode, width of each gaps between the resonators varying along the each of resonators to make either of electrostatic or electromagnetic coupling between the resonators stronger than the other.
摘要:
A coaxial type microwave filter having an outer conductor and at least one inner conductor supported in the outer conductor has a strip transmission line extending from an external strip-line circuit to the inner conductor through an opening in the outer conductor. The strip transmission line includes a dielectric member forming an integral part of the dielectric substrate of the external circuit and a thin layer of conductive strip also forming an integral part of the conductive film pattern of the external circuit. The extending strip transmission line is electromagnetically coupled with the inner connector to permit the two microwave circuits to be interconnected with no use of a connector.
摘要:
A tuning device including a conductive housing in which are suspended a dielectric substrate. A pair of first and second resonant circuits is disposed on the substrate in parallel with each other. Each resonant circuit is formed by an elongated conductive film and a capacitive element. A grounded conductive strip film is provided between the transmission lines of the first and second resonant circuits to reduce the interstage coupling between the two transmission lines with a resultant decrease in spacing between them.
摘要:
A comb-line bandpass filter comprising an enclosure or outer conductor and a plurality of inner conductors arranged parallel in the outer conductor. Adjacent to one end of each inner conductor a body of dielectric material is attached to provide a larger diameter, lumped capacitance section while providing a lumped inductance section in the remainder of the inner conductor. A conductive layer, conductively coupled to the outer conductor, encircles the dielectric body to act as a shield between adjacent inner conductors so that the coupling between them is concentrated in the inductive section. Overall size of the comb-line filter is reduced by reduction both in axial length of the inner conductors and the spacing between them.