Nonresonating Modes Do It Better!: Exploiting Additional Modes in Conjunction With Operating Modes to Design Better Quality Filters

Bastioli, Simone; Snyder, Richard V.

doi:10.1109/mmm.2020.3027934

Cited by 34 publications

(21 citation statements)

References 73 publications

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“…Note that a combination of a capacitive or inductive and constant values in the NRNs is also admissible. Non-resonating modes [33] can also be considered by this general synthesis framework, as they can be either treated as resonators with ω i being away from the pasband or approximated by NRNs. In relation to the formula (13), it should be pointed out that it can be replaced by a more-complex frequency-dependent expression for the node reactance, such as the one associated to a set of resonators-e.g., doublet, triplet, or quadruplet.…”

Section: Filters With Non-ideal Arbitrary Frequency Variant Inverts and Non-resonating Nodesmentioning

confidence: 99%

Inverse Nonlinear Eigenvalue Problem Framework for the Synthesis of Coupled-Resonator Filters With Non-Resonant Nodes and Arbitrary Frequency-Variant Couplings

Mrozowski¹,

Lamęcki²,

Mul³

et al. 2021

Preprint

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A novel, general circuit-level description of coupled-resonator microwave filters is introduced in this paper. Unlike well-established coupling-matrix models based on frequency-invariant couplings or linear frequency-variant couplings (LFVCs), a model with arbitrary frequency-variant coupling (AFVC) coefficients is proposed. The engineered formulation is more general than prior-art ones and can be treated as an extension of previous synthesis models, since constant or linear couplings are special cases of arbitrary frequency dependence. The suggested model is fully general, allows for AFVCs with highly nonlinear (even singular) characteristics, loaded or unloaded non-resonating nodes (NRNs), frequency-dependent source-load coupling, multiple frequency-variant cross-couplings, and{/}or multiple dispersive couplings for connecting the source and load to the filter network. The model is accompanied by a powerful synthesis technique that is based on the zeros and poles of the admittance or scattering parameters and the eigenvalues of properly defined eigenproblems. In the most general case, the zeros and poles of the admittance or scattering parameters are related to solutions of nonlinear eigenvalue problems. The synthesis is defined as an inverse nonlinear eigenvalue problem (INEVP) where the matrix is constructed from three sets of eigenvalues. This is accomplished by optimization using an iterative nonlinear least-squares solver with excellent convergence property. Finally, third- and fifth-order examples of bandpass filter topologies involving AFVCs are shown, and the experimental validation of the proposed theory is presented through the manufacturing and characterization of a microstrip filter prototype with transmission zeros (TZs)

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Section: Filters With Non-ideal Arbitrary Frequency Variant Inverts and Non-resonating Nodesmentioning

confidence: 99%

Inverse Nonlinear Eigenvalue Problem Framework for the Synthesis of Coupled-Resonator Filters With Non-Resonant Nodes and Arbitrary Frequency-Variant Couplings

Mrozowski¹,

Lamęcki²,

Mul³

et al. 2021

Preprint

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“…9 further indicates that the WS, NS and NP filters all feature asymmetric transmission zeros unaccounted for in the simple all-pole coupling model. This may be due to unintended cross-coupling between elements, or by the presence of non-resonating modes [11]. IV.…”

Section: Filter Implementationsmentioning

confidence: 99%

Vertically Integrated Combline Filters in Multilayer PCB

Stander¹

2021

Preprint

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Vertical stacking of planar line resonators in multilayer media is an effective footprint reduction technique for high order filters, but strong broadside line coupling often negates the possibility of narrowband filters. It is shown that vertically stacking combline resonators with rotated centerlines leads to moderate bandwidth filters. Four variations of a 5th order filter are demonstrated, achieving 1.92 – 3.3 dB IL over 10% FBW around 10 GHz while occupying between 6.62 – 22.47 mm2 surface area on a 7 layer PCB.

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“…Several methods for realization of TZs in waveguide technology have been proposed in the literature, including cross-coupling between non-adjacent resonators and the use of multi-mode cavities [3]- [9], extracted pole synthesis method [10] and the use of inverters based on frequency-dependent coupling sections [11]. A relatively new approach of realizing pseudo-elliptic response that has attracted attention in the last decade is the use of non-resonating modes to create additional energy paths [1], [12], [13]. The non-resonating modes can either be propagating or evanescent at the passband of the filter and they can provide additional energy paths and thus can be used to implement arbitrarily located finite frequency transmission zeros (TZ) while still keeping the inline topology.…”

Section: Introductionmentioning

confidence: 99%

“…The center of the enlarged width cavity can be easily adjusted relative to the center axis of the feeding waveguides to achieve flexibility in realization of the finitefrequency TZ at the desired location. A singlet structure presented in [29] and also explained in [13] again uses an enlarged width rectangular waveguide cavity but with T E 301 mode as the resonating mode. The width dimension of the realized singlet is significantly larger than that of a standard rectangular waveguide.…”

Section: Introductionmentioning

confidence: 99%

“…The main advantage of the proposed singlet arrangement over those presented in [16], [17], [29] is that the proposed structure does not require any increase in cross-sectional dimensions beyond those of a standard waveguide. However, the enlarged width cavity based singlets of [13], [16], [17], [29] do present great flexibily in setting the location of TZ at the required frequency by just adjusting the center of singlet cavity relative to the centers of feeding rectangular waveguides. This is easily achieved since these singlets are not constrained by the crosssectional dimensions of the feeding waveguides.…”

Section: Introductionmentioning

confidence: 99%

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Inline Waveguide Pseudo-Elliptic Filters Using Non-Resonating Modes With Folded-Waveguide Resonators

Chaudhary

Ahmed

2021

IEEE Access

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In this paper, a new structure to implement inline waveguide pseudo-elliptic filters using folded-waveguide (FWG) resonators along with non-resonating modes has been proposed. The basic structure is an FWG resonator fed by a rectangular waveguide through inductive irises. The T E 10 mode of the feeding rectangular waveguide excites both dominant and first higher order modes in the FWG structure. The dominant mode of the FWG acting as a non-resonating mode creates an alternate energy path from source to load thus producing a transmission zero (TZ), while the first higher order mode acts as the resonant mode resulting in a pole. The structure therefore acts as a singlet capable of realizing a pole and a TZ either below or above the passband depending on the offset of the feeding irises from the center of the FWG resonator and relative to each other. The structure also provides flexibility in shifting the FWG center axis relative to the feeding rectangular waveguides, thus giving more coupling control and realizing wider range of singlet responses. The proposed singlet structure does not require any increase in the cross-sectional size relative to the standard rectangular waveguide. Two prototype filters using the proposed singlet structures have been designed, manufactured and tested. Measurements show good agreement with the simulations, verifying the feasibility of the proposed structure.INDEX TERMS Waveguide filters, pseudo-elliptic response, transmission zeros, bandpass filters.

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Nonresonating Modes Do It Better!: Exploiting Additional Modes in Conjunction With Operating Modes to Design Better Quality Filters

Cited by 34 publications

References 73 publications

Inverse Nonlinear Eigenvalue Problem Framework for the Synthesis of Coupled-Resonator Filters With Non-Resonant Nodes and Arbitrary Frequency-Variant Couplings

Inverse Nonlinear Eigenvalue Problem Framework for the Synthesis of Coupled-Resonator Filters With Non-Resonant Nodes and Arbitrary Frequency-Variant Couplings

Vertically Integrated Combline Filters in Multilayer PCB

Inline Waveguide Pseudo-Elliptic Filters Using Non-Resonating Modes With Folded-Waveguide Resonators

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