A Generalized Coupling Matrix Extraction Technique for Bandpass Filters With Uneven-Qs

Hu, Han; Wu, Ke-Li

doi:10.1109/tmtt.2013.2296744

Cited by 54 publications

(40 citation statements)

References 18 publications

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“…It can be observed in Figure the responses obtained by a previous implementation of the method about

S_{21}

is rather poor compared with the novel approach in the frequency far away from bandpass domain, and in the bandpass domain, the

S_{11}

extracted by the previous approach higher than normal value of return loss. With the novel approach in the bandpass domain, the

S_{21}

and

S_{11}

are fitted very well compared with the previous method in . The issue about the method in is mainly caused by VF whose shortcoming is that only positive frequency samples can be specified.…”

Section: Examplementioning

confidence: 91%

“…To show the improvement presented by the novel approach compared with the previous ones, the result obtained using a generalized analytical extraction method is compared with the novel approach shown in Figure . The CAT1 in Figure represents the polynomial response with CM obtained as proposed in . The accuracy of CAT1 S11 fitting is rather poor in the edge of the bandpass, and CAT1 S21 fitting is rather poor far away from bandpass.…”

Section: Examplementioning

confidence: 99%

“… Responses obtained from a previous implementation of the method compared with the method we present for an 8‐order coaxial–resonator filter. CAT is obtained by ours.…”

Section: Examplementioning

confidence: 99%

“…In fact, the constant filter Q factors can be used effectively only when all the resonators have a relatively equal loss distribution. For eliminating the uneven‐Q effect, a generalized analytical approach to deal with a filter with lossy and unevenly distributed Q factors is proposed in . Whereas, the rational polynomials of the Y ‐parameters are solved by a VF method, dealing with filters with unevenly distributed Q factors will bring some problems.…”

Section: Introductionmentioning

confidence: 99%

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Extracting Coupling Matrix From Lossy Filters With Uneven-Qs Using Differential Evolution Optimization Technique

Cao

Liu

Yuan

et al. 2018

Int J RF Microw Comput Aided Eng

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This article presents an approach based on differential evolution (DE) for extracting coupling matrix (CM) and the uneven unloaded Qs from measured S‐parameters of a narrow band coaxial‐resonator filter with losses. Different from analytical extraction methods and traditional optimization methods, nonideal effects and uneven‐Qs are chosen as unknown parameters to be optimized. In the optimization process, the polynomials of the S‐parameters of a filter can be obtained by the Cauchy method after the unknown parameters are given. Once the rational polynomials having been obtained; the CM with an assigned topology can be extracted. The DE approach will obtain optimal parameters when the difference between the measured S‐parameters and the extracted S‐parameters is minimized, and then the CM and the unloaded Qs of each resonator can be determined using well established techniques. The approach is useful and can be used in computer‐aided turning of microwave filters. Two examples are presented to illustrate the validity of the proposed method.

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“…It can be observed in Figure the responses obtained by a previous implementation of the method about

S_{21}

is rather poor compared with the novel approach in the frequency far away from bandpass domain, and in the bandpass domain, the

S_{11}

extracted by the previous approach higher than normal value of return loss. With the novel approach in the bandpass domain, the

S_{21}

and

S_{11}

are fitted very well compared with the previous method in . The issue about the method in is mainly caused by VF whose shortcoming is that only positive frequency samples can be specified.…”

Section: Examplementioning

confidence: 91%

Section: Examplementioning

confidence: 99%

“… Responses obtained from a previous implementation of the method compared with the method we present for an 8‐order coaxial–resonator filter. CAT is obtained by ours.…”

Section: Examplementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Extracting Coupling Matrix From Lossy Filters With Uneven-Qs Using Differential Evolution Optimization Technique

Cao

Liu

Yuan

et al. 2018

Int J RF Microw Comput Aided Eng

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show abstract

“…The flatness of group delay across the operating bandwidth of a filter [26], [27] is an important design requirement for many applications. On a conventional Cartesian plot of τ (ω), target masks are normally introduced to indicate its minimum and maximum allowable values, as seen in Fig.…”

Section: B Equalization Of Transmission Response Group Delaymentioning

confidence: 99%

Extended Capabilities of the 3-D Smith Chart With Group Delay and Resonator Quality Factor

Müller¹,

Codesal²,

Moldoveanu

et al. 2017

IEEE Trans. Microwave Theory Techn.

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Abstract-This paper extends the capabilities of the 3-D Smith chart for representing positive and negative differential-phase group delay and the associated loaded resonator quality factor, displayed simultaneously with scattering (S)-parameters. Here, mathematical concepts, inspired from elementary differential geometry and topology, are used to implement 3-D projections. It is shown that a condition for a circuit to exploit negative differential-phase group delay is that its S-parameter winding number should be ≥ 0 (relative to its origin). Finally, exemplar network responses that exhibit both positive and negative differential-phase group delay and loaded resonator quality factor are shown with the 3-D Smith chart. The convenience of being able to simultaneously display a wider range of parameters on one visualization platform, with the 3-D Smith chart, may help to speed-up the design and analysis of microwave circuits by the user.Index Terms-Computer-aided design (CAD), differentialphase group delay, negative group delay (NGD), non-Foster, quality factor, Smith chart.

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Improved diagnosis of lossy resonator bandpass filters using Y -parameters

Wang

Peng

2015

Int J RF and Microwave Comp Aid Eng

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This article presents a generalized coupling matrix (CM) extraction technique directly from the measured or electromagnetic simulated admittance parameter (Y-parameters) of a narrow band cross-coupled resonator bandpass filter with losses. The characteristic polynomials corresponding to the Y-parameters rather than the S-parameters are derived and then determined by the Cauchy method. Once determining the characteristic polynomials, the complex poles and residues of Y-parameters are also determined. Using these complex poles and residues, the complex CM can be obtained by a sequence of similarity transformations, and then the desired extracted CM and unloaded Q for each resonator are obtained from this complex CM. To verify the effectiveness of the proposed method, three filter CM extraction examples are demonstrated.

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A Generalized Coupling Matrix Extraction Technique for Bandpass Filters With Uneven-Qs

Cited by 54 publications

References 18 publications

Extracting Coupling Matrix From Lossy Filters With Uneven-Qs Using Differential Evolution Optimization Technique

Extracting Coupling Matrix From Lossy Filters With Uneven-Qs Using Differential Evolution Optimization Technique

Extended Capabilities of the 3-D Smith Chart With Group Delay and Resonator Quality Factor

Improved diagnosis of lossy resonator bandpass filters using Y -parameters

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