Synthesis of Microwave Resonator Diplexers Using Linear Frequency Transformation and Optimization

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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“…The derivation process of Eq. is similar to the method in , where the group delay of a diplexer is derived. Note that Eq.…”

Section: Filter Diagnosis Examplesmentioning

confidence: 99%

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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“…Due to the interaction of two filters composing the diplexer, the characteristics of a microstrip diplexer are different from the responses of the individual two microstrip filters. The complexity of the interaction makes the design of a microstrip diplexer complicated [4].…”

Section: Introductionmentioning

confidence: 99%

Compact and High Isolation Microstrip Diplexer for Broadband and Wlan Application

Deng

Zhao²,

Fu³

et al. 2013

PIER

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Abstract-In this paper, a compact and high isolation microstrip diplexer is designed for broadband and wireless local area network (WLAN) application, simultaneously. The bandpass filter (BPF) for broadband channel is formed by three-coupled-line structure and two short stubs with different size loaded in 50 Ω feed lines, and the BPF for WLAN channel consists of two coupling quarter-wavelength resonators (QWR) and one open stub loaded in short parallel-coupling feed structure. Multiple transmission zeros can be generated due to their intrinsic characteristics, so the broadband BPF with sharp skirt and wide upper-stopband performance and the WLAN BPF with sharp roll-off and lower-stopband characteristic can be realized. The tapped stub not only can generate new transmission zeros to deepen the stopband, but also can connect other BPF as an its part without deterioration of in-band performance. Hence, a compact microstrip diplexer combines of two BPFs without the extra junction matching network. The mutual loading effect approximately equivalent to a coupled QWR can also generate new transmission zero at the passband edge to improve the isolation. A microstrip diplexer with the 3 dB fractional bandwidths (FBW) of 80% for broadband channel and 5% for WLAN channel is designed and fabricated. Good agreement between the simulated and measured results is observed.

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“…The most popular structures to form the planar diplexer are combing two bandpass filters with different frequencies and two matching circuits [10,11]. However, this idea may increase insertion loss and circuit size [12,13]. A novel structure with compact size using microstrip-line technology is introduced in [14].…”

Section: Introductionmentioning

confidence: 99%

Design of Diplexer With Rotationally Symmetric Structure

Wong¹,

Liu²,

Wang³

et al. 2013

PIER C

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This paper presents an approach to the design of novel diplexers with pairs of transmission zeros for each output port. A rotationally symmetric structure with shorted circuited stubs is proposed to achieve diplexer operation, and the diplexer exhibits a good filtering performance with a pair of transmission zeros allocated at two sides of the passbands as well. The analysis of the rotationally symmetric structure bandpass filter is also presented in this paper in detail. Moreover, the interdigital coupled-lines are introduced to improve the out-of-band performance of the proposed rotationally symmetric diplexer. In order to verify the proposed structure, first a diplexer with rotationally structure operating at 2.4/2.73 GHz with simulated insertion loss of 1.217/0.930 dB is designed and simulated, then a diplexer with interdigital coupled-lines operating at 5/5.8 GHz with measured insertion loss of 1.524/1.524 dB is designed, simulated and measured to improve the passband selectivity, and the measured results are in good agreement with simulated ones.

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Synthesis of Microwave Resonator Diplexers Using Linear Frequency Transformation and Optimization

Cited by 12 publications

References 18 publications

Improved diagnosis of lossy resonator bandpass filters using Y -parameters

Improved diagnosis of lossy resonator bandpass filters using Y -parameters

Compact and High Isolation Microstrip Diplexer for Broadband and Wlan Application

Design of Diplexer With Rotationally Symmetric Structure

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