Design of compact branch-line couplers using -equivalent artificial transmission lines

Tseng, Chao‐Hsiung; Wu, Cheng-Zhou

doi:10.1049/iet-map.2010.0464

Cited by 26 publications

(20 citation statements)

References 11 publications

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“…Consequently, multiple evaluation of circuit performance within standard EMdriven design routines, involving conventional optimization algorithms or parameter sweeps, is extremely time-consuming and rarely accomplished in practice. 9 A bulk of previously reported works rely on problem decomposition and focus exclusively on satisfying the operating conditions imposed on circuit building blocks, unavoidably neglecting the effect of parasitic cross-couplings on performance of the assembled circuit [10][11][12] This typically leads to poor device performance and inferior miniaturization rates being merely a byproduct of meeting the operation requirements by the circuit building blocks. Lately, novel design methodologies have been developed to partially mitigate some the aforementioned difficulties.…”

Section: Introductionmentioning

confidence: 99%

Inverse modeling for fast design optimization of small-size rat-race couplers incorporating compact cells

Koziel

Kurgan

2018

Int J RF Microw Comput Aided Eng

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In the paper, a framework for computationally‐efficient design optimization of compact rat‐race couplers (RRCs) is discussed. A class of hybrid RRCs with variable operating conditions is investigated, whose size reduction is obtained by replacing ordinary transmission lines with compact microstrip resonant cells (CMRCs). Our approach employs a bottom‐up design strategy leading to the development of compact RRCs through rapid design optimization of its building blocks and a subsequent fine tuning to account for parasitic cross‐coupling effects. The fundamental component of the proposed method is an inverse CMRC surrogate model, covering a wide range of cell electrical parameters, and enabling a convenient adjustment of coupler bandwidth. Having the surrogate model established, it is possible to produce close‐to‐optimum CMRC dimensions at a negligible computational cost. The subsequent correction step requires only up to two electromagnetic simulations of the CMRC. The proposed method is demonstrated by designing an RRC for several operational bandwidths. Experimental results are also provided.

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Section: Introductionmentioning

confidence: 99%

Inverse modeling for fast design optimization of small-size rat-race couplers incorporating compact cells

Koziel

Kurgan

2018

Int J RF Microw Comput Aided Eng

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“…State‐of‐the‐art strategies for the development of compact microwave circuits almost exclusively consider design problems of narrowband components, miniaturized by means of single‐element slow‐wave structures . Majority of them utilize transmission line (TL) theory to provide closed‐form design formulas applicable for the target devices, but also require some sort of EM‐based fine‐tuning procedure to account for inaccuracies of the utilized models . Design closure is typically realized using repetitive parameter sweeps or direct optimization, both being computationally expensive .…”

Section: Introductionmentioning

confidence: 99%

“…Miniaturization of distributed-element passive circuits is an important topic of contemporary microwave engineering. [1][2][3][4][5][6] Currently prevailing approach to circuit size reduction is based on decomposition of a conventional circuit and subsequent replacement of its building blocks with so-called slow-wave structures whose role is to approximate the characteristics of their conventional counterparts while offering an increased electrical to physical length ratio. 5,6 Slow-wave structures are typically realized as intricate combinations of high-impedance strips and low-impedance stubs or line sections.…”

Section: Introductionmentioning

confidence: 99%

“…1,4,6 Majority of them utilize transmission line (TL) theory to provide closed-form design formulas applicable for the target devices, but also require some sort of EM-based fine-tuning procedure to account for inaccuracies of the utilized models. 1,2,4 Design closure is typically realized using repetitive parameter sweeps or direct optimization, both being computationally expensive. 22 This difficulty can be alleviated through surrogatebased optimization (SBO), 8 which relies on iteratively corrected fast low-fidelity models (surrogates) replacing high-fidelity EM models.…”

Section: Introductionmentioning

confidence: 99%

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Fast optimization of quasi‐periodic slow‐wave structures with applications to broadband microwave coupler miniaturization

Kurgan

Koziel

2016

Int J Numerical Modelling

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This work discusses design optimization of quasi‐periodic slow‐wave structures in the context of wideband branch‐line coupler miniaturization. Size reduction is achieved by using slow‐wave structures as substitutes for conventional transmission lines of the reference circuit. Selection of a specific cell realization as well as determination of a repetition factor of the quasi‐periodic slow‐wave structure is accomplished by optimization‐based theoretical studies. The principal design procedure involves cell optimization using electromagnetic simulations, local response surface approximation modeling of the single cell, and surrogate‐based optimization of the slow‐wave structure composed of cascaded cell approximation models. Surrogate‐assisted design closure is subsequently applied to account for T‐junction effects neglected in the preceding stages of the design process. The final coupler exhibits high‐performance operation over a 31% bandwidth and occupies only one third of the reference circuit area. The component obtained in this work illustrates the highest bandwidth‐to‐size ratio as compared to state‐of‐the‐art structures reported in the literature. In addition, the feasibility of the approach is confirmed by experimental data.

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“…However the large size of conventional branch line Manuscript couplers sometimes used to be a problem because all the arms of this structure must be of electrical length of 1/4 λ for the applications at the UHF frequency band. The one method to miniaturize this large size of branch line couplers is to use lumped elements such as capacitors or inductors [7]- [10].…”

Section: Introductionmentioning

confidence: 99%

Design of HTS 3 dB Hybrid Coupler Using Lumped Elements for Radio Astronomy

Chung

2013

IEEE Trans. Appl. Supercond.

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In this work, we report on a highly miniaturized 3 dB coupler for radio astronomy. To do this, we made the equivalent circuits with normal branch line couplers with eight impedances. Then, we analyzed them using an ABCD matrix under even and odd mode excitation, and successfully designed miniaturized 3 dB couplers with the lumped elements of four inductors and four capacitors. To avoid the increasing of surface resistance due to the narrow line width, we used a high-T c superconducting thin film. The designed high-T c superconducting 3 dB couplers were fabricated using YBCO thin film on MgO substrate. Experimental results including bandwidth, center frequency, and phase difference between |S 12 | and |S 13 | are reported. Especially, our couplers were about five times smaller than normal branch line couplers, and had a significant broad band of 15 MHz.

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Design of compact branch-line couplers using -equivalent artificial transmission lines

Cited by 26 publications

References 11 publications

Inverse modeling for fast design optimization of small-size rat-race couplers incorporating compact cells

Inverse modeling for fast design optimization of small-size rat-race couplers incorporating compact cells

Fast optimization of quasi‐periodic slow‐wave structures with applications to broadband microwave coupler miniaturization

Design of HTS 3 dB Hybrid Coupler Using Lumped Elements for Radio Astronomy

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