A waveguide transition includes a ridge waveguide section with a first ridge part running along a first wall having a first distance to an opposing second wall. The waveguide transition comprises a partial H-plane waveguide section with an electrically conducting foil that comprises a longitudinally running foil slot ending a certain edge distance before a foil edge that faces the ridge waveguide section. The ridge waveguide section and the partial H-plane waveguide section overlap during a transition section that has a first end at a transition between the second wall and a third wall. There is a second distance between the first wall and the third wall that exceeds the first distance. The transition section has a second end where the first ridge part ends by a transversely running second ridge part that crosses the foil slot and connects to a third wall.

The present applications at least describes a method of making a tuned ceramic filter. The method includes printing an oversized pattern of ceramic material on a ceramic filter. The method also include removing, at a first tune location of the ceramic filter, a first amount of the ceramic material using a laser to shrink the oversized pattern. The method also includes comparing a coupling matrix of the ceramic filter after the removing step with a coupling matrix of a prototype of the ceramic filter. The method includes a step of generating a tune vector based upon a difference between the coupling matrix of the ceramic filter and the coupling matrix of the prototype filter. Further, the method includes a step of iteratively modifying the removing of the ceramic material using femto-second laser at the first tune location to have a coefficient of the tune vector corresponding to the first tune location to converge toward zero.

The present applications at least describes a method of making a tuned ceramic filter. The method includes printing an oversized pattern of ceramic material on a ceramic filter. The method also include removing, at a first tune location of the ceramic filter, a first amount of the ceramic material using a laser to shrink the oversized pattern. The method also includes comparing a coupling matrix of the ceramic filter after the removing step with a coupling matrix of a prototype of the ceramic filter. The method includes a step of generating a tune vector based upon a difference between the coupling matrix of the ceramic filter and the coupling matrix of the prototype filter. Further, the method includes a step of iteratively modifying the removing of the ceramic material using femto-second laser at the first tune location to have a coefficient of the tune vector corresponding to the first tune location to converge toward zero.

A directional coupler includes a main line for transmitting a high frequency signal, a sub line electromagnetically coupled to the main line, a termination circuit for terminating one end portion of the sub line, and a variable filter that has an input terminal and an output terminal and the input terminal is connected to another end portion of the sub line. The variable filter is a filter unit circuit having one frequency band as a pass band or a stop band, and in the filter unit circuit, a variable passive element for shifting a frequency in the pass band or the stop band is disposed.

A directional coupler includes a main line for transmitting a high frequency signal, a sub line electromagnetically coupled to the main line, a termination circuit for terminating one end portion of the sub line, and a variable filter that has an input terminal and an output terminal and the input terminal is connected to another end portion of the sub line. The variable filter is a filter unit circuit having one frequency band as a pass band or a stop band, and in the filter unit circuit, a variable passive element for shifting a frequency in the pass band or the stop band is disposed.

Reflectionless low-pass, high-pass, band-pass, band-stop, all-pass, all-stop, and multi-band filters, as well as a method for designing such filters is disclosed, along with a method of enhancing the performance of such filters through the use of unmatched sub-networks to realize an optimal frequency response, such as the Chebyshev equal-ripple response. These filters preferably function by absorbing the stop-band portion of the spectrum rather than reflecting it back to the source, which has significant advantages in many different applications. The unmatched sub-networks preferably offer additional degrees of freedom by which element values can be assigned to realize improved cutoff sharpness, stop-band rejection, or other measures of performance.

Reflectionless low-pass, high-pass, band-pass, band-stop, all-pass, all-stop, and multi-band filters, as well as a method for designing such filters is disclosed, along with a method of enhancing the performance of such filters through the use of unmatched sub-networks to realize an optimal frequency response, such as the Chebyshev equal-ripple response. These filters preferably function by absorbing the stop-band portion of the spectrum rather than reflecting it back to the source, which has significant advantages in many different applications. The unmatched sub-networks preferably offer additional degrees of freedom by which element values can be assigned to realize improved cutoff sharpness, stop-band rejection, or other measures of performance.

A tunable filter for adjustable filtering between a minimum frequency and a maximum frequency includes a transmission line designed to transmit a signal and having longitudinal axis. The tunable filter further includes a two-dimensional capacitor array including step-tunable capacitors located along the transmission line, a first dimension of the two-dimensional capacitor array being along the longitudinal axis and a second dimension of the two-dimensional capacitor array being located perpendicular to the longitudinal axis. The tunable filter further includes a controller coupled to each of the step-tunable capacitors and designed to control each of the step-tunable capacitors independently to be in a biased mode or in an unbiased mode based on a desired frequency response of the tunable filter.

A tunable filter for adjustable filtering between a minimum frequency and a maximum frequency includes a transmission line designed to transmit a signal and having longitudinal axis. The tunable filter further includes a two-dimensional capacitor array including step-tunable capacitors located along the transmission line, a first dimension of the two-dimensional capacitor array being along the longitudinal axis and a second dimension of the two-dimensional capacitor array being located perpendicular to the longitudinal axis. The tunable filter further includes a controller coupled to each of the step-tunable capacitors and designed to control each of the step-tunable capacitors independently to be in a biased mode or in an unbiased mode based on a desired frequency response of the tunable filter.

Disclosed herein are printed circuit boards with at least one signal trace situated over or under a reference plane. The reference plane includes a broadband common-mode filter that comprises looping and parallel structures etched into the reference plane. The looping structure includes an even number of side arms, and the parallel structure comprises an even number of interior arms, wherein each of the side arms extends toward the parallel structure, and each of the interior arms extends toward the looping structure. The at least one signal trace is substantially parallel to the side arms and to the interior arms, and is situated between a first half of the even number of side arms and a second half of the even number of side arms and between a first half of the even number of interior arms and a second half of the even number of interior arms.