Abstract:
Disclosed is a millimeter wave waveguide structure adapted for operation with negative resistance devices, such as solid state avalanche breakdown diodes, at frequencies up to about 170 GHz or higher. A central portion of the structure is formed by a cylindrical metallic impedance transformer and bias pin which has a major face thereof substantially parallel to a common lower waveguide wall of the structure. A negative resistance device is DC coupled between this common waveguide wall and one edge of the impedance transformer, so that the impedance transformer also provides the required DC bias to the negative resistance device. Other portions of the waveguide structure include a first upper waveguide wall, immediately adjacent one side of the impedance transformer, and this wall, together with the common lower waveguide wall, forms a tuning cavity into which a sliding tuning short is positioned. Another portion of the waveguide structure includes a second, upper waveguide wall immediately adjacent the opposite side of the impedance transformer, and this wall together with the common lower waveguide wall, confines millimeter wave power from the negative resistance device to a predetermined path and direction. Suitable waveguide transition means are coupled to the second upper waveguide wall for coupling the above structure to a full height waveguide.
Abstract:
An oscillator (100) includes a resonator (218) having a mirco-strip (217). The micro-strip (217) couples an inductive component (221) to a capacitive portion (219). To tune the oscillator (100), a number of cuts are made on the pad (221) in order to restrict the signal flow. The width of these cuts determine the degree of restriction posed on the signal flow. This controllable restriction of the signal flow provides the circuit (100) with enhanced tunability.
Abstract:
A coplanar waveguide based microwave monolithic integrated circuit (MMIC) oscillator chip (14) having an active oscillator element (16) and a resonant capacitor (18) formed thereon is flip-chip mounted on a dielectric substrate (12). A resonant inductor (22) is formed on the substrate (12) and interconnected with the resonant capacitor (18) to form a high Q-factor resonant circuit for the oscillator (10). The resonant inductor (22) includes a shorted coplanar waveguide section (24) consisting of first and second ground strips (24b,24c), and a conductor strip (24a) extending between the first and second ground strips (24b,24c) in parallel relation thereto and being separated therefrom by first and second spaces (26a,26b) respectively. A shorting strip (24d) electrically interconnects adjacent ends of the conductor strip (24a) and first and second ground strips (24b,24c) respectively. A dielectric film (34) may be formed over at least adjacent portions of the conductor strip (24 a) and first and second ground strips (24b,24c). The resonant inductor (22) is adjusted to provide a predetermined resonant frequency for the oscillator (10) by using a laser (40) to remove part of the dielectric film (34) in the first and second spaces (26a,26b) for fine adjustment, and/or to remove part of the shorting strip (24d) at the ends of the first and second spaces (26a,26b) for coarse adjustment.
Abstract:
The oscillator comprises a main cavity housing a Gunn diode and auxiliary cavity branching laterally and allowing only inlet of the harmonic components.The auxiliary cavity is provided with harmonic tuning means for varying the reactance of the auxiliary cavity to the harmonic components. The load impedance seen by the Gunn diode is thus varied.
Abstract:
A temperature compensated cavity oscillator comprising a resonant coaxial cavity of which the outer conductor is constructed of dissimilar materials. The end walls and adjacent portion of the outer conductor of the coaxial cavity are made of a first conductive material having a first temperature coefficient of expansion. Interposed between the first conductive material of the outer conductor, the middle portion of the outer conductor is made from a second conductive material having a second temperature coefficient of expansion. A tuning rod is displaced through the middle portion of the cavity and capacitively coupled to a center coaxial conductor to provide mechanical tuning of the oscillation frequency and for varying the frequency of the cavity with temperature such that the temperature characteristics of the oscillating element are compensated to produce a substantially stable oscillating frequency.
Abstract:
The IC television tuner has a tunable oscillator and a fixed oscillator, two mixer stages and a filter in between. This tuner operates at two intermediate frequencies the first of which lies in the GHz range. The two oscillators are coupled through hybrid rings.
Abstract:
A high efficiency mode avalanche diode oscillator is disclosed. The avalanche diode and a tuning capacitor are connected in parallel at a high microwave voltage point at one end of a resonant transmission line section electrically one-eighth wavelength long at the operating frequency of the oscillator, so as to match the complex impedance of the diode to a load impedance, and to provide the high efficiency mode of operation.
Abstract:
A voltage-controlled oscillator and a method capable of precisely adjusting a frequency shift amount are provided irrespective of a fluctuation in characteristics of elements such as a strip-line. A center tap 19 is formed in a strip-line 16 of a resonator. A switching element 20 is connected to the center tap 19, and this switching element 20 is turned ON, so that the center tap is shortcircuited to the ground so as to vary the oscillating frequency. A slit A1 is conducted in the vicinity of the center tap 19 along the strip-line 16 and directed toward a shortcircuited end 17 of the strip-line, so that a frequency shift amount is adjusted. Also, a slit B1 is conducted in the vicinity of the shortcircuited end 17 along the strip-line 16 and directed toward the center tap 19, so that a frequency shift amount is adjusted. Also, trimming points are provided on the side of a hot terminal 18 from the center tap 19, and also provided on the side of the shortcircuited end 17 from the center tap 19, and further a slit is conducted along an intersecting direction of the strip-line 16, so that a shift amount is adjusted.
Abstract:
A voltage controlled oscillator provides a trimming stub (3) for adjusting a free-running frequency in parallel to a microstrip line resonator (4). This arrangement makes it possible to easily perform fine adjustment of a free-running frequency used in the voltage controlled oscillator capable of supplying 2 GHz or higher oscillating frequency.
Abstract:
A method (100) for tuning a voltage controlled oscillator by changing electrical circuit parasitics includes a first step (102) of providing a voltage controlled oscillator circuit on a circuit board and a plurality of different metal lids each having different numbers, sizes and locations of holes. Each different lid presents a different electrical circuit parasitic to the voltage controlled oscillator. In a second step (104), the voltage controlled oscillator frequency is measured, and the frequency shift needed to achieve a desired operating frequency is calculated in a third step (106). In a fourth step (108), a lid is chosen that will present the parasitics needed to provide the amount of frequency shift needed. As a last step (110), the chosen lid is attaching to the circuit board to obtain the desired nominal operating frequency from the voltage controlled oscillator.