Conductus, Inc.

Avago Technologies General IP (singapore) Pte. Ltd.

Avago Technologies Wireless IP (singapore) Pte. Ltd.

Superconductor Technologies Inc.

Shen Ye

Paul D Bradley

Ji-Fuh Liang

Michael Louis Frank

Genichi Tsuzuki

Jeesu Kim

Herbert L Ko

A duplexer includes a transmit filter and an integrated receive filter configured to filter a receive signal from an antenna. The integrated receive filter includes a receive filter portion having multiple acoustic resonator filter elements and a matched balun configured to convert a single-ended input signal, received at a single-ended input of the matched balun from a single-ended output of the receive filter portion, to a differential output signal. The matched balun being is located in place of a phase matching inductor of the receive filter portion, eliminating need for the phase matching inductor of the receive filter portion and a phase matching inductor of the matched balun. Impedance at the single-ended input of the matched balun includes a complex conjugate of impedance at the single-ended output of the receive filter portion.

Integrated receive filter including matched balun

A filter device is provided for filtering signals. The filter device includes multiple series resonators, multiple shunt resonators and multiple cross-coupling circuits. The series resonators are connected in series between an antenna and one of a transmitter or a receiver. The shunt resonators are respectively connected between at least one of the series resonators and a ground voltage. The cross-coupling circuits are configured to bypass at least two series resonators of the multiple series resonators and at least one shunt resonator of the multiple shunt resonators.

Resonator filter with multiple cross-couplings

A single-chip duplexer, interfacing a receiver and a transmitter with a common antenna, includes transmit and receive filters, an annular sealing ring and a conductive stripe. The transmit filter is connected between the antenna and the transmitter, and has a transmit passband. The receive filter is connected between the antenna and the receiver, and has a receive passband different from the transmit passband. The annular sealing ring is connected between a surface of the chip and a surface of a cap to form a sealed cavity between the chip and the cap. The conductive stripe extends across at least a portion of the surface of the chip between the transmit filter and the receive filter, the conductive stripe being directly connected to the sealing ring and electrically connected to ground. The conductive stripe provides at least one of magnetic shielding and capacitive shielding between the transmit filter and the receive filter.

Single-chip duplexer with isolation shield between transmit and receive filters

A duplexer interfacing a receiver and a transmitter with an antenna includes first and second filters. The first filter includes at least four first series resonators, four first shunt resonators respectively connected between the four first series resonators and ground voltage, and a mutual inductance commonly connected between two adjacent first shunt resonators. The second filter includes at least four second series resonators, four second shunt resonators respectively connected between the four second series resonators and the ground voltage, and a cross-coupling capacitor connected between a first capacitor node connected to at least one of the second series resonators and a second capacitor node connected to one of the second shunt resonators, and an inductor connected in series between second capacitor node and ground. Three of the second series resonators and the second shunt resonator to which the cross-coupling capacitor is connected are between the first and second capacitor nodes.

Duplexer having resonator filters

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.

Microstrip filter including resonators having ends at different coupling distances

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. The third section runs substantially parallel to an edge of the second resonator that is not profoundly influenced by the source of field disturbance. A second section connects the first and third sections.

Superconductive stripline filter utilizing one or more inter-resonator coupling members

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. Filters utilizing multiple resonators of the invention are also described. The integration of the series and shunt capacitors results in a more compact resonator and filter layout, allows broader manufacturing tolerances, and allows for more layout flexibility than is attainable with the technology of the prior art.

Superconductive filter with capacitive patches providing reduced cross-coupling

A resonator and filter including the resonator is disclosed. The resonator () includes an open conductive loop () with folded transmission line segments () 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 (W) that is not substantially greater than the width of the loop (W). 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.

Resonator having folded transmission line segments and filter comprising the same

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.

Modular frequency division filter

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. Laying out the components with the bandpass filter first can prevent (or significantly reduce) intermodulation generated by those components due to out-of-band interference signals.

Method and apparatus for minimizing intermodulation with an asymmetric resonator

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.

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Cupertino, CA, United States of America

Shen Ye