Symmetrical and Asymmetrical Edge-Coupled-Line Impedance Transformers with a Prescribed Insertion Loss Design

A miniaturized wideband four‐way filtering power divider (FPD) is presented in this article. It is composed of unequal‐width three‐coupled‐lines (TCLs), stepped‐impedance open‐circuited stubs, and isolation resistors. By using two groups of the unequal‐width TCLs and the stepped‐impedance open‐circuited stubs, size reduced four‐way FPD with wideband filtering responses and out‐of‐band rejection is realized. Besides, good output ports matching and isolation are obtained by inserting two types of air‐bridge resistors. In the theoretical analysis section, the impedance matrix of the unequal‐width TCL is introduced, for the first time, and rigorous closed‐form design equations for the proposed FPD are also derived. Moreover, the methodology for computer‐aided design is given based on the design equations. For demonstration, a prototype operating at 1.5 GHz is designed, fabricated, and measured. The measured results validate the 80% bandwidth with more than 17 dB out‐of‐band rejection, more than 14 dB isolation and more than 15 dB return loss at all output ports. Compare with the reported four‐way FPD with similar bandwidth, a size reduction of 74% is obtained.

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“…Based on the calculated parameters, the dimensions of the TCL are achieved using the theory in Reference 36. First, according to

Z_{e}^{a}

and

Z_{o}^{a}

, the dimensions of the symmetrical two‐coupled‐line composed by A‐line (width W a and gap S a ) is obtained.…”

Section: Design and Implementationmentioning

confidence: 99%

Synthesis of miniaturized wideband four‐way filtering power divider consisting of unequal‐width three‐coupled‐lines

Liu

Guan

et al. 2021

Int J RF Microw Comput Aided Eng

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“…Coupled line was used as a direct current (DC) choked circuit to block the DC signal from transmission. These impedance-transforming DC blocks with one-section coupled line were studied in [10][11][12][13]. However, one-section symmetric coupled line cannot be directly applied for a wideband impedance transformer with in-band Chebyshev response.…”

Section: Introductionmentioning

confidence: 99%

Synthesis design of a wideband impedance transformer consisting of two‐section coupled lines

2017

IET Microwaves, Antennas & Propagation

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An impedance transformer employing two‐section coupled lines is presented in this study, which can achieve a wide operating band or passband with three reflection zeros. A direct synthesis approach is proposed and applied to the design of this transformer with the prescribed Chebyshev‐function frequency response. If the impedance–transformation ratio, passband return loss (RL), and operating bandwidth are properly specified, all the required design parameters of this transformer can be explicitly gained. Furthermore, a special region for realisable impedance–transformation ratio and operating bandwidth with respect to the passband equal‐ripple RL is extensively investigated. As such, various sets of design curves are numerically derived and graphically demonstrated for synthesis design of authors’ proposed impedance transformer. As an example, a 50–25 Ω impedance transformer with the 50% fractional bandwidth and 20 dB passband RL is designed, fabricated, and measured to confirm the theoretical predictions in the experiment.

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“…The asymmetric coupled lines provide more flexible impedance transform properties than the symmetrical coupled lines and are used in various microwave circuit applications such as directional couplers , filters , baluns , and impedance transformers .…”

Section: Introductionmentioning

confidence: 99%

A symmetric coupled line equivalent circuit model for asymmetric coupled lines

Park

Lee

2016

Int J RF and Microwave Comp Aid Eng

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A new equivalent circuit model is proposed for an asymmetric coupled line based on a symmetric coupled line. The proposed equivalent circuit consists of a symmetric coupled line and two ideal transformers to represent an asymmetric coupled line and can be easily incorporated into the existing microwave and RF circuit simulators. This makes it easier to model and simulate the asymmetric coupled line circuits in terms of simple symmetric coupled lines. Using the proposed equivalent circuit model, it is shown that an asymmetric coupled line coupler is electrically equivalent to a symmetric coupled line coupler with transformed port impedances and the relation between the two couplers is investigated through the established equivalence. The validity of the proposed model is confirmed through the analysis of the directional couplers and the impedance transformers involving the asymmetric coupled lines. V C 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:277-282, 2016.

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Symmetrical and Asymmetrical Edge-Coupled-Line Impedance Transformers with a Prescribed Insertion Loss Design

Cited by 24 publications

References 12 publications

Synthesis of miniaturized wideband four‐way filtering power divider consisting of unequal‐width three‐coupled‐lines

Synthesis of miniaturized wideband four‐way filtering power divider consisting of unequal‐width three‐coupled‐lines

Synthesis design of a wideband impedance transformer consisting of two‐section coupled lines

A symmetric coupled line equivalent circuit model for asymmetric coupled lines

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