摘要:
A mixer for outputting an intermediate frequency signal as the result of mixing of a radio frequency signal and a local oscillator signal which are inputted into the mixer. The mixer comprises a balanced-to-unbalanced conversion circuit and a bridge-coupled diode circuit and the balanced-to-unbalanced conversion circuit is constructed of first and second rat race circuits, one being for the radio frequencey signal and comprising a first ring-shaped line and the other being for the local oscillator signal and comprising a second ring-shaped line. The mixer is arranged to include a substrate having first and second pattern-forming surfaces and the first ring-shaped line of the first rat race circuit is formed as a pattern on the first pattern-forming surface of the substrate and the second ring-shaped line of the second rat race circuit is formed as a pattern on the second pattern-forming surface. The bridge-coupled diode circuit is positioned on the first pattern-forming surface thereof and inside the patterned first ring-shaped line.
摘要:
A microwave band frequency synthesizer comprises first and second phase-locking loops. The first phase-locking loop includes a first voltage controlled oscillator, a variable frequency divider and a first multiplier and generates an output signal whose frequency changes at the rate of a unit frequency change width of the oscillator. The second phase-locking loop includes a first fixed frequency divider for frequency-dividing the output signal of the first phase-locking loop to provide a phase comparison reference signal of a frequency higher than that phase-compared in the first phase-locking loop, a second voltage controlled oscillator, a second fixed frequency divider for frequency dividing an output of the second voltage controlled oscillator, a second phase comparator for phase-comparing a frequency-divided an output signal of the second fixed frequency divider and the phase comparison reference signal in order for phase-locking of the second voltage controlled oscillator, and a second multiplier for multiplying the output signal from the second voltage controlled oscillator to provide a microwave band signal.
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 push-push oscillator comprises: a resonator having a transmission line and a capacitance connected to the transmission line in parallel; an oscillator for producing two outputs having an antiphase relation therebetween in response to the resonator; and a differential signal producing circuit for producing a differential signal in accordance with difference between these two outputs. These outputs can be obtained from the resonator. The transmission lines comprise strip line or microstrip line which is curved to form an open loop. The transmission line may be made of a dielectric material and is curved to form an open loop whose both ends are connected to a capacitance. The resonator may further comprise two second transmission lines, each provided to an end of the transmission line, these two second transmission lines facing each other with a given distance therebetween, the distance and length of the second transmission lines being determined such that necessary capacitance is provided. Impedance of each portion of the resonator is determined to miniaturize the resonator. The differential signal producing circuit comprises a balanced to unbalanced converting circuit.
摘要:
A resonator having a strip line, the strip line comprising: a first portion forming an open loop; and two second portions, each provided to each end of the first portion, the second portions facing each other with a given distance therebetween, the distance and length of the second portion being determined such that necessary capacitance is provided. The capacitor is provided instead of a discrete capacitor for saving space and for reducing dielectric loss therein. A second resonator further comprises second and third capacitor having a semicircle strip-line patterns for providing capacitances between ends of the first portion and grounded planes which decrease the resonance frequency so that size of the second resonator are reduced. A third resonator also comprises the first capacitor, but arranged outside of the first portion. Capacitance of the first capacitor can be increased by teeth provided to the second portions. A filter comprises plural third resonators so arranged that coupling between the resonators is obtained by one selected from magnetic-field coupling through the first portions, electromagnetic-field coupling through first and second portions, and electric-field coupling through second portions.
摘要:
In a coaxial filter arrangement having a plurality of coaxial resonators each having a bottomed metallic cylinder interposed between a dielectric plate and one end of a center conductor of each resonator, the peripheral wall portion of the metallic cylinder is received in the bore of an outer conductor having an open end and a closed end connected to the other end of the center conductor. In one embodiment, the bottom of the metallic cylinder has a convex portion at its center so that the bottom center projects outwardly. In another embodiment, an annular metallic member is interposed between the dielectric plate and the outer surface of the flat bottom of the metallic cylinder. Since the distance between bottoms of metallic cylinders of adjacent resonators is made large with this arrangement, influence due to leakage flux of electromagnetic field is small, while stray capacitance is negligibly small, thereby providing a filter having high performance and low loss.
摘要:
A coaxial dielectric resonator for VHF and/or UHF band comprising a generally cylindrical dielectric having inner surface and outer surface. The inner and outer surfaces of the dielectric are respectively covered by outer and inner conductors and these conductors are connected at one end of the dielectric. An adjusting screw for adjusting resonance frequency is provided at the other end of the dielectric which is covered by a lid while holding a gap between the adjusting screw and the lid. A microwave filter using a plurality of the coaxial dielectric resonator is further described.
摘要:
There is disclosed herein a millimeter-wave/submillimeter-wave oscillator comprising a mirror and a diffraction grating so as to form a Fabry-Perot type resonator. The mirror, being a concave mirror or a plane mirror, and the diffraction grating are disposed in facing and spaced relation to each other. The diffraction grating has a plurality of channels extending in a direction normal to a surface of the mirror so that the oscillator has a comb-like configuration. A plurality of oscillation elements are mounted on portions within the channels of the diffraction grating.
摘要:
A hemispherical dielectric resonator is arranged on a conductive substrate with a flat surface of the resonator in contact with the conductive substrate and fixed by a pair of fixing blocks. The dielectric resonator is fed with a signal feeder at a position at one side of the resonator such that intensity of the electric field is higher at that position. The fixing blocks contact a portion of the dielectric resonator where the intensity of the electric field is of a local minimum.
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.