A microwave switched multiplexer having a bandpass f between frequencies f1 and f2, f=f1f2, the multiplexer comprising an input microwave resonant waveguide; an output microwave resonant waveguide; and, n transmission channels where n>1, each transmission channel coupled to the input microwave resonant waveguide and the output microwave resonant waveguide, each transmission channel having a transmission bandpass at a center frequency within f, the center frequencies of the transmission channels being equally spaced apart in frequency by f/n; each transmission channel comprising (a) an input resonator coupled to the input microwave resonant waveguide; (b) an output resonator coupled to the output microwave resonant waveguide: (c) a center resonator coupled to the input and output resonators, the three resonators being coupled together in cascade; (d) a tuning mechanism connected to the center resonator and adapted to be switched between on and off states, in the on state the resonant frequency of the center resonator being the same as that of the input and output resonators and in the off state the resonant frequency of the center resonator being outside the bandpass f.

A microwave switched multiplexer having a bandpass At between frequencies f.sub.1 and f.sub.2, f=f.sub.1f.sub.2, the multiplexer comprising n signal channels, where n>1, each signal channel having a signal bandpass at a center frequency within M, the center frequencies of the signal channels being equally spaced apart by f/n; each signal channel comprising (a) a switch having first, second and third ports, the switch being adapted to be switched between a transmit position in Which the first port is connected to the second port, a receive position in which the first port is connected to the third port and an off position in which the first port is not connected to either second or third ports; (b) a common line extending from an antenna end to the first port, the common; line .Math. comprising an input resonator and a center resonator connected together in cascade, the center resonator being coupled between the resonator and the first port.

Hybrid structures, filters and duplexers are disclosed. According to one aspect, a radio frequency (RF) duplexer includes a common resonator coupled to at least one chamber of an air cavity filter, a first ceramic waveguide filter. CWGF, having a first opening in a first CWG wall of the first CWGF, the first opening at least partially aligned with a first window of the common resonator to couple energy between the common resonator and the CWGF, and a second CWGF having a second opening in a second CWG wall of the second CWGF, the second opening at least partially aligned with the second window of the common resonator to couple energy between the air cavity resonator and the CWGF.

A ceramic monoblock RF filter for the transmission of an RF signal comprising a block of dielectric material including opposed top and bottom surfaces, opposed longitudinal side surfaces, and opposed transverse side surfaces. A plurality of spaced apart through-hole resonators extend through the block and terminate in openings in the top and bottom surfaces of the block. A second plurality of grounded RF signal blocking through-holes extend through the block and terminate in respective openings in the top and bottom surfaces of the block. The grounded through-holes are located and positioned in a relationship off-set and on opposite sides of the first plurality of through-hole resonators for blocking the coupling of the RF signal between RF signal input/outputs and selected ones of the first plurality of resonators and also between non-adjacent ones of the first plurality of resonators.

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 dielectric waveguide port coupling structure comprising: a surface-metalized dielectric block having a first surface and a second surface that is opposite to the first surface; a blind groove opened in the first surface of the dielectric block; wherein the blind groove comprises a main portion and an extension portion each extending from the main portion toward a corresponding frequency blind hole that is located nearby and opened in the first surface of the dielectric block, the blind groove having its walls metalized; and a coupling through-hole penetrating from a bottom wall of the blind groove to the second surface of the dielectric block, and used for connecting with an input or output device to input or output a signal, wherein the coupling through-hole is metalized. A transmission line is on the bottom wall of the blind groove and extends from the coupling through-hole along a corresponding extension portion.

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.

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 comprises a monolithic metal body and a metal cover capacitively coupled to the body without any galvanic contact.

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 multi-band RF monoblock filter including at least three RF signal filters defined in the monoblock of dielectric material by resonators defined in part by through-holes extending through the block. In one embodiment, two of the RF signal filters are in a co-linear and side-by-side relationship and the third filter is in a parallel and side-by side relationship with one of the two other RF signal filters. A pattern of conductive material defines two end and one interior RF signal input/output on the block top surface. The end RF signal input/outputs are located at opposite ends of the block and the central RF signal input/output is located between the two co-linear and side-by-side RF filters. An RF signal is transmitted through the one end RF signal input/output, the two parallel and side-by-side RF signal filters, and the central RF signal input/output and also through the other end RF signal input/output, one of the co-linear and side-by-side RF filters, and the central RF signal input/output.