摘要:
A microwave mixing circuit comprises a main transmission line having an input port for receiving an input high frequency and an output port, a band pass filter responsive to a local oscillation frequency, first and second band stop filters, and a mixing diode connected to the output port. The local oscillation frequency applied via the band pass filter to the main transmission line is prevented from being transmitted toward the input port because of the first band stop filter, while an image frequency produced by the diode is reflected by the second band stop filter to be applied to the diode.
摘要:
A wide band analog frequency divider circuit operable at a high frequency in the GHz band. The analog frequency divider circuit comprises an LC series circuit having a capacitor and an inductor connected between the anode and the cathode of a diode, and means for applying a forward bias to the diode. The input signal is supplied from the anode side of the diode, and the output is delivered from the cathode side, or the anode side if the cathode is grounded.
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:
In a voltage-controlled oscillator having an LC resonant circuit including a varactor circuit so that resonant frequency is controlled by a D.C. bias or control voltage applied to the varactor circuit, three or more varactors are connected in series in one embodiment so that a high-frequency voltage applied to the varactor circuit is divided into a plurality. The varactors may be connected in the same direction or opposite direction. In another embodiment, a plurality of series circuits of varactors are connected in parallel to provide the varactor circuit, where each series circuit comprises two or more varactors. A series-parallel connection of a plurality of varactors may be arranged in a matrix. In order to reduce undesirable stray capacitance, some or all varactors are attached to a printed circuit board so that they are normal to the plane of the printed circuit board. In one embodiment an auxiliary printed circuit board is employed so that some varactors are spaced from a main circuit board. The voltage-controlled oscillator of the invention shows high carrier-to-noise ratio throughout a wide frequency range.
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.
摘要:
A tuning device including a conductive housing in which is 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. An image frequency trapping circuit is arranged to intersect one of the transmission lines to absorb the signal at the image frequency. A grounded conductive strip film is provided adjacent to and parallel with each of the transmission lines and so spaced therefrom that the characteristic impedances of the transmission lines are made equal to each other.
摘要:
A coaxial dielectric resonator for VHF-UHF band comprises a generally cylindrical dielectric body having a thick portion, a thin portion and a stepped portion interposed between the thick and thin portion. The outer and inner surfaces of the dielectric body are respectively covered by outer and inner conductors. Thus the resonator can be regarded as a series circuit of two lines having different impedance from each other. The axial length of the thick and thin portions may be changed so as to change electrical characteristics. With the provision of thick and thin dielectric portions, the spurious resonance frequencies may be set to values other than integral multiples of the fundamental resonance frequency. The stepped portion may be rounded or replaced with a tapered portion so that impedance gradually changes at the stepped or tapered portion from the thick portion to the thin portion or vice versa.