Abstract: A resonator of a planar circuit type is provided for receiving a signal from an input end and transmitting a signal to an output end. The resonator includes: (a) a dielectric substrate; (b) a ground plane including a layer of conductive material formed on the bottom surface of the substrate; (c) an inductor formed on the top surface of the substrate and connected to the input and output ends; and (d) a series capacitor connected in parallel to the inductor, wherein the series capacitor includes two patches of conductive material formed on the top surface of the substrate, each patch being connected to one respective end of the resonator. Each patch also forms a shunt capacitor with the ground plane, and the capacitance of the shunt capacitor constitutes the majority of capacitance between the ground plane and the end of the resonator that is connected to the patch. The conductive material may be a superconductor, including oxide superconductors.

Abstract: A resonator and filter including the resonator is disclosed. The resonator (100) includes an open conductive loop (100) with folded transmission line segments (124, 134) extending from the adjacent ends of the loop. Of each transmission line segment, the portion emanating from the respective end of the loop is positioned generally along-side the corresponding portion of the other transmission line segment. That is, the two transmission line segments are folded away from each other. The resonator can be generally elongated in shape, with the loop at one end of the long axis and the transmission line segments at the other. The transmission line segments occupy a footprint (W2) that is not substantially greater than the width of the loop (W1). The filter includes multiple resonators of the invention, each resonator being coupled to at least another or the resonators. The resonators can be positioned in a side-by-side fashion, with the long axes of the resonators parallel or anti-parallel to one another.

Abstract: The present invention is a modular frequency division filter having an antenna port that connects to two or three transmission paths. Each transmission path includes either a band pass filter or a duplexer to separate the received signal by frequency. Frequency phase shifters or shunt inductors may be included to further enhance the frequency separation. Following frequency separation, the separated signal is transceived by a device operating at the respective separated frequency.

Abstract: A method and apparatus to control intermodulation in a circuit for filtering over the air signals by creating an asymmetric resonator is disclosed. By creating the asymmetric resonator, the intermodulation from out of band signals is reduced while keeping the filter size relatively unchanged. In general, the intermodulation is reduced by lowering the current density in the resonator (e.g., so as to maintain the linearity of the electrical characteristics of the resonator), and more specifically by utilizing the principle that the inductive elements in a resonator experience the largest current changes. Therefore, the size of the inductor is changed in order to accommodate the larger power. An additional feature of the present invention is that not every inductive element of the filter needs to be enlarged. Generally only the first (or alternatively the first and second) resonators need to be increased in size. Another feature of the present invention is the physical order in which the filters are laid out.

Abstract: A method and apparatus to provide appropriate coupling between resonators in an HTS microstrip filter are disclosed. Primary and secondary couplings between a pair of resonators are utilized. With a given spacing, the primary coupling is fixed, while the secondary coupling can have different magnitude. In addition, the secondary coupling can have the same phase or opposite phase as the primary coupling. With different combinations, large or small bandwidth filters can be made without very small or very large spacing between resonators. The same cross coupling layout configuration may be designed to achieve either positive or negative results.

Abstract: The present invention is a modular frequency division filter having an antenna port that connects to two or three transmission paths. Each transmission path includes either a band pass filter or a duplexer to separate the received signal by frequency. Frequency phase shifters or shunt inductors may be included to further enhance the frequency separation. Following frequency separation, the separated signal is transceived by a device operating at the respective separated frequency.

Abstract: An inter-resonator coupling scheme for a filter is disclosed. An inter-resonator coupling member is located between successive resonators in the filter. By adjusting the length and/or the proximity of the inter-resonator coupling member relative to the adjacent resonators, the ratio of energy transferred from resonator to resonator (via the inter-resonator coupling member) may be increased and/or decreased. By increasing the ratio of energy transferred from resonator to resonator, the bandwidth of the filter is increased and is made relatively insensitive to tuning which may occur via manipulation of field disturbances introduced by tuning tips. The inter-resonator coupling member is made of a conductive or superconductive material and contains at least three sections. The first section runs substantially parallel to an edge of the first resonator that is not profoundly influenced by the source of field disturbance.

Abstract: A resonator and filter including the resonator is disclosed. The resonator (100) includes an open conductive loop (100) with folded transmission line segments (124, 134) extending from the adjacent ends of the loop. Of each transmission line segment, the portion emanating from the respective end of the loop is positioned generally along-side the corresponding portion of the other transmission line segment. That is, the two transmission line segments are folded away from each other. The resonator can be generally elongated in shape, with the loop at one end of the long axis and the transmission line segments at the other. The transmission line segments occupy a footprint (W2) that is not substantially greater than the width of the loop (W1). The filter includes multiple resonators of the invention, each resonator being coupled to at least another or the resonators. The resonators can be positioned in a side-by-side fashion, with the long axes of the resonators parallel or anti-parallel to one another.

Abstract: A closed conductive loop for use in planar circuits to realize shunt capacitors instead of conductive patches is disclosed. The closed conductive loop may be formed on a planar substrate or extend to multiple conductive layers in a multi-layer circuit. The use of closed conductive loops as shunt capacitors offers possibilities of more flexible circuit layout, reduced circuit footprint and comparable or improved performance as compared to using conductive patches as shunt capacitors.

Abstract: A method and apparatus to control intermodulation in a circuit for filtering over the air signals by creating an asymmetric resonator is disclosed. By creating the asymmetric resonator, the intermodulation from out of band signals is reduced while keeping the filter size relatively unchanged. In general, the intermodulation is reduced by lowering the current density in the resonator (e.g., so as to maintain the linearity of the electrical characteristics of the resonator), and more specifically by utilizing the principle that the inductive elements in a resonator experience the largest current changes. Therefore, the size of the inductor is changed in order to accommodate the larger power. An additional feature of the present invention is that not every inductive element of the filter needs to be enlarged. Generally only the first (or alternatively the first and second) resonators need to be increased in size. Another feature of the present invention is the physical order in which the filters are laid out.

Abstract: A closed conductive loop for use in planar circuits to realize shunt capacitors instead of conductive patches is disclosed. The closed conductive loop may be formed on a planar substrate or extend to multiple conductive layers in a multi-layer circuit. The use of closed conductive loops as shunt capacitors offers possibilities of more flexible circuit layout, reduced circuit footprint and comparable or improved performance as compared to using conductive patches as shunt capacitors.

Abstract: A microwave filter has a plurality of resonators and at least one transmission line mounted on a substrate having a ground plane. The filter can have input and output couplings that are transmission lines formed on the substrate or it can have input and output probes. The resonators have one or more gaps extending entirely therethrough, the gaps splitting the resonators into two or more slices. The transmission lines extend into the gap to couple energy into or out of a resonator or between two adjacent resonators. The transmission lines can have tapered ends or can be located off center so that they are closer to one side of a gap than to another side.

Abstract: A planar dual mode filter has one or more resonators with L-shaped sections that are oriented back to back to one another. The filter can be constructed by adjusting the size of a gap between the back to back sections and adjusting the offset distance between adjacent sections. Further, coupling between adjacent resonators can be controlled by adjusting a distance between the adjacent resonators. The filters can be co-planar, stripline, suspended microstripline or microstripline. The filters have a film on a substrate with a ground plane. The film can be gold, silver or copper or it can be a ceramic material that becomes superconductive at cryogenic temperatures.

Abstract: Microstrip/stripline transmission lines have a plurality of strips on a substrate where strips are separated by a gap. This arrangement results in a reduced maximum current density compared to previous transmission lines with the same power handling capability. The strips can have the same width or different widths. The gaps can have the same width or different widths. The transmission lines can be used in filters and resonators and can be made of high temperature superconductive materials.