A quadruple mode bandpass filter has at least one cavity resonating in four independent orthogonal modes simultaneously. Preferably, the filter has two cavities, one cavity being a quadruple mode cavity and the remaining cavity being either a single mode, dual mode, triple mode or quadruple mode cavity. By introducing a resonant feedback coupling into filters of the present invention, the number of transmission zeros produced by the filter is equal to the order of the filter. Previous filters have cavities resonating in either a single, dual or triple mode and the maximum number of transmission zeros is equal to the order of the filter minus two.

Quadruple mode filter

An externally temperature-compensated microwave resonator comprises a microwave resonator and an external temperature compensator. The microwave resonator is a multi-cavity waveguide. The cavities are configured side-by-side and coupled through irises. The external temperature compensator is oriented and configured to effect a change in volume of the cavities when the resonator and compensator undergo a temperature gradient. The compensator deflects a wall portion of the resonator to accordingly counteract a change in volume of the cavity caused by a temperature gradient.

A microwave resonator having an external temperature compensator

A circuit includes an input signal line, a high performance resonant element connected to the input signal line, and an output signal line connected to the high performance resonant element. The high performance resonant element is a via.

High performance resonant element

A waveguide filter includes one or more resonator cavities which extend between an input to the filter and an output from the filter. Each resonator cavity in the filter has a center line with a chosen extension and a mechanical length. The mechanical length of the center line of each resonator cavity forms one of the parameters that determine the electrical length of the resonator cavity. The filter forms part of a microwave unit. At least one of the resonator cavities of the filter has a curved extension with respect to its center line.

Waveguide filter with a resonator cavity having inner and outer edges of different lengths

A microwave cavity including a pair of opposing clamshell halves, such halves comprised of a metal selected from the group consisting of silver, copper, or a silver-based alloy, wherein the cavity is further characterized as exhibiting a dominant TE 011 mode is provided together with an embodiment wherein the interior concave surfaces of the clamshell halves are coated with a superconductive material. In the case of copper clamshell halves, the microwave cavity has a Q-value of about 1.2×10 5 as measured at a temperature of 10K and a frequency of 10 GHz.

Clamshell microwave cavities having a superconductive coating

A method for designing low loss cylindrical TE 011 mode resonators which permits selective placement of a transmission null at a frequency near the TE 011 resonance frequency. The frequencies of the TE 211 and TE 311 modes, that are naturally excited in the resonator, are controlled by the angular displacement of the resonator input port and output port and by the relative amplitude of the TE 011 mode compared to the TE 211 and TE 311 modes. Proper placement of the transmission nulls improves the selectivity of the TE 011 resonator, and/or can be used to filter out unwanted noise at the frequency of the transmission null. A lumped constant analog circuit model is presented to assist in design of the resonator.

Terrance D. Lingren

Papers

Method for improving selectivity in cylindrical TE011 filters by TE211 /TE311 mode control