Abstract: A low-pass filter comprises input and output transmission lines, a high impedance, series transmission line coupling the input and output transmission lines, a first meandered transmission line having one or more pairs of coupled transmission lines and one or more transition transmission lines connecting respective pairs of coupled transmission lines together, wherein one of the coupled transmission lines is connected to the input transmission line, and a second meandered transmission line having one or more pairs of coupled transmission lines and one or more transition transmission lines connecting respective pairs of coupled transmission lines together, wherein one of the coupled transmission lines is connected to the output transmission line. A high-pass filter is similar to the low-pass filter, except it has a pair of series coupled transmission lines in place of the series transmission line. The transmission lines are formed on a dielectric subtrate.

Abstract: A design methodology for a DRO that facilitates the development of the DRO. The methodology involves providing an electrical length of approximately 180 degrees or a multiple thereof from a region interior to a field effect transistor to a puck-resonator line interaction region, providing an electrical length of approximately 180 degrees or a multiple thereof from a region interior to the field effect transistor to the signal end of a source feedback transmission line, and providing an electrical length of approximately 90 degrees or an odd multiple thereof from a varactor diode signal ground to a puck-tuning line interaction region. Other aspects relate to a DRO resonator transmission line and a DRO tuning transmission line having a portion formed on a higher dielectric substrate to concentrate the electromagnetic field, and a portion on a lower dielectric substrate to expand the electromagnetic field near the dielectric resonator puck.

Abstract: A directional coupler characterized as having improved directivity. The directional coupler and methodology uses enhanced destructive interference to reduce the leakage at the output port of a signal incident at the coupled port of the coupler thereby giving the coupler improved directivity. The directional coupler creates this enhanced destructive interference by the introduction of impedance discontinuities in the coupled transmission lines. The impedance discontinuity in the coupled transmission lines can take on many forms, such as recesses at the coupling sides of the coupled transmission lines, protrusions at the non-coupling sides of the coupled transmission lines, or both. Another directional coupler is capable of being tuned for different coupling levels. This coupler comprises adjacent conductors between the coupled transmission lines that are connected, as required, to the coupled lines to change the coupling level.

Abstract: A phase detector having improved dynamic range, frequency range, multiplication factor range, and detector gain. The detector converts a reference signal into a square wave. The square wave signal causes a step recovery diode in a sampling phase detector to trigger on a leading edge to obtain a more consistent and more precise sampling of an oscillator signal. The phase detector includes a saturated amplifier to convert the reference signal to a square wave signal, a transformer to impedance match the amplifier with the sampling phase detector and to generate a balanced output of the square wave signal. The sampling phase detector generates a phase error signal indicative of the phase difference between the reference signal and the oscillator signal. The sampling phase detector includes balanced outputs having oppositely-phased phase error signals. A potentiometer is provided to reduce or eliminate any imbalances in the oppositely-phased phase error signals.

Abstract: A temperature-compensating tuning device is disclosed for tuning and temperature stabilizing the resonant frequency of a dielectric resonator. The tuning device comprises a tuning element in the form of a cylindrical shaft, an inner sleeve coaxially around the tuning element and mating therewith by corresponding sets of threads, and an outer sleeve coaxially around the inner sleeve, and mating therewith by corresponding sets of threads. The outer surface of the outer sleeve may also include threads for mating with threads of a dielectric resonator enclosure. Rotation of the tuning element, inner sleeve and/or outer sleeve can move the tuning element in proximity to a dielectric resonator, which provides the resonant frequency tuning effect. The tuning element, inner and outer sleeves are made of temperature expanding material to cause the tuning element to move in proximity of the dielectric resonator with temperature changes to provide temperature stability to the resonant frequency.

Abstract: An RF/Microwave oscillator is disclosed that has the high-Q, low-loss, and phase noise performance of a DRO, without the need of a dielectric resonator to achieve such performance. The RF/Microwave oscillator includes a field effect transistor having a drain coupled to an output circuit, a source coupled to a series feedback circuit, and a gate coupled to a resonator circuit. Each of these circuits are comprised of cascaded pairs of coupled transmission lines designed to resonate at the operating frequency of the oscillator. The RF/Microwave oscillator may also include a frequency-adjustable bias circuit, a frequency-adjustable FET gate return, and a frequency tuning circuit.

Abstract: A frequency-adjustable direct current biasing circuit is disclosed for providing a DC bias voltage or a DC connection to ground for an RF or microwave circuit without substantially affecting the RF or microwave signal of the circuit. The biasing circuit includes a transmission line having a first portion for connection to the RF circuit and a second portion connected to a low-impedance-to-ground structure, such as a bypass capacitor or a DC path to ground. The electrical length between the first and second portions is about 90 degrees. The biasing circuit further includes an open ended tuning stub coupled to the transmission line that has a length that is adjustable. By adjusting the length of the tuning stub, the biasing or grounding circuit can provide better isolation for RF energies at different selected frequencies. Also disclosed herein is a dielectric resonator oscillator (DRO) that uses the frequency-adjustable biasing circuit.