Methods and devices suitable for monitoring the frequency of microwave tunable filters in real time. The frequency readout relies on the natural response of such a filter when excited by a pulse. Methods of measuring an operating frequency of a pole in a tunable filter include measuring a number of cycles in a natural response in the filter when the filter is excited by an electric current pulse, and determining a resonance frequency based on the number of cycles measured in the natural response. Such a method can provide the operating frequency information in a binary digital format, making it relatively easy to read and process. A measuring resonator may be mounted to the filter resonator and connected by a common actuator.

A resonant cavity filter has a housing having a resonator mounted therein, a tuning screw that comprises a head portion, a metallic tuning element and a dielectric spacer interposed between the head portion and the metallic tuning element. The tuning screw is mounted for coaxial insertion into an interior of the resonator to adjust a frequency response of the resonant cavity filter.

An input/output apparatus of a multiplexer is provided, including: a main tap and at least two branch taps of the main tap, where each of the at least two branch taps is configured to couple to a different resonant cavity in the multiplexer, and the at least two branch taps include a first branch tap and a second branch tap; a coupling polarity of the first branch tap is opposite to that of the second branch tap; and a coupling calculation frequency of the second branch tap is closest to a coupling calculation frequency of the first branch tap. The input/output apparatus of the multiplexer enables two channels with closest frequencies to use different coupling polarities. Because the coupling polarities are different, signals naturally do not interfere with each other, and signal interference between channels is eliminated in principle. The embodiments of the present disclosure further provide a corresponding multiplexer.

A cascading microwave switch (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set, wherein the series coupling causes the first Josephson device in an open state to reflect back to an input port of the first Josephson device a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and the n.sup.th Josephson device in the open state to reflect back to an input port of the n.sup.th Josephson device a signal of an n.sup.th frequency from the multiplexed signal.

A cascading microwave switch (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set, wherein the series coupling causes the first Josephson device in an open state to reflect back to an input port of the first Josephson device a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and the n.sup.th Josephson device in the open state to reflect back to an input port of the n.sup.th Josephson device a signal of an n.sup.th frequency from the multiplexed signal.

A duplexer includes a cavity resonator defining an opening covered by an RF plate. The RF plate defines an opening through which a pass-band tuning pipe extends and is secured thereto. A collar is attached to one end of the pipe, and at least one steel set screw extends into the interior of the collar, the at least one end having a soft (e.g., brass) tip. A tuning plunger is slidingly positioned within the pass-band tuning pipe. A rod is attached to a first end of the tuning plunger and extends through the collar, the rod being fabricated from a material harder than the tip of the at least one set screw. The at least one set screw is configured for tightening down on the rod to secure the rod and tuning plunger in place. A trimmer capacitor is positioned in the RF plate.

A dielectric filter, a duplexer, and a communications device are provided. The dielectric filter includes a dielectric body, and a wideband filtering structure and a narrowband filtering structure that are disposed in the dielectric body. The wideband filtering structure includes a groove disposed on a first surface of the dielectric body and configured to adjust a frequency position of a passband of the wideband filtering structure; and at least one first resonator including a through hole penetrating the bottom of the groove and a second surface of the dielectric body; and an open loop located on a bottom surface of the groove and is disposed around an opening of the through hole. The narrowband filtering structure includes at least one second resonator including a blind hole disposed on the second surface of the dielectric body. The first surface and the second surface of the dielectric body are disposed oppositely.

The present invention relates to a switchable filter comprising: a filter unit in which a first filter group for filtering the frequency of a first frequency band is provided on one surface thereof and a second filter group for filtering the frequency of a second frequency band is provided on the other surface thereof on the basis of a center partition wall; and a frequency band switching unit, which moves to be adjacent to or separated from the one surface or the other surface of the filter unit, and thus converts a frequency band into the first frequency band or the second frequency band. Therefore, the deterioration of RF characteristics is prevented and selective conversion between frequency bands is facilitated.

A PIM test bench including a first duplexer, having a first port connected via a first filter to a third port and a second port connected via a second filter to the third port. The first port is fed by signal sources providing RF signals at first and second frequencies. A spectrum analyzer is connected to the second port. A device under test is connected between said third port and a third port of a second duplexer. Each of the first and second ports of the second duplexer is connected to a PIM optimized load and/or a standard load. The second duplexer is preferably identical to the first duplexer. For minimizing self-intermodulation, at least the first duplexer comprises at least one filter component and a metal housing. The housing further includes a monolithic metal body and a metal cover capacitively coupled to the body without any galvanic contact.

The present disclosure relates to dielectric duplexers. One example dielectric duplexer includes a dielectric body, where an input/output structure, a tap, a first resonance structure, and a second resonance structure are provided on surfaces of the dielectric body. The tap and the input/output structure are provided on different surfaces of the dielectric body. The tap and the input/output structure are located between the first resonance structure and the second resonance structure. A first resonator consists of the first resonance structure and the dielectric body around the first resonance structure, and a second resonator consists of the second resonance structure and the dielectric body around the second resonance structure. A conducting layer covers a surface of the input/output structure, the tap, the first resonance structure, and the second resonance structure, and the conducting layer covers the surface of the dielectric body except a region around the input/output structure.