Journals / Dicle Üniversitesi Mühendislik Fakültesi Mühendislik Dergisi / 2026 / Cilt: 17 Sayı: 2

Development of an Equivalent Circuit Topology for a Directional Coupler

Yönlü Bağlaştırıcı için Eşdeğer Devre Topolojisi Geliştirilmesi

İbrahim Genç(SULEYMAN DEMIREL UNIVERSITY)0000-0002-1693-6685
Mahmut Ahmet Gözel(SULEYMAN DEMIREL UNIVERSITY)0000-0002-0360-7188
Mesud Kahriman(SÜLEYMAN DEMİREL ÜNİVERSİTESİ)0000-0003-0731-0936
Pages
—
Publication Date
2026-07-18
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

Analysis results show that the Mean Absolute Error value, which was 4.52 dB in the basic models, was reduced to 0.67 dB in the proposed final topology.

📌 3 Key Takeaways

🎯
Objective & Hypothesis:In the design and analysis processes of microstrip directional couplers, full-wave electromagnetic simulations provide high accuracy.
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Key Findings & Data:This study presents an improved lumped element equivalent circuit topology based on the segmentation principle in transmission line theory, which enables the rapid and accurate modeling of the distributed electromagnetic behavior of physical structures.
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Conclusion & Impact:Analysis results show that the Mean Absolute Error value, which was 4.52 dB in the basic models, was reduced to 0.67 dB in the proposed final topology.
🔬Design:Modeling & Simulation
📍Scope:Comprehensive Sample
⚙️Variables:Yönlü bağlaştırıcı · Eşdeğer devre topolojisi · İletim hattı teorisi

Abstract

In the design and analysis processes of microstrip directional couplers, full-wave electromagnetic simulations provide high accuracy. Still, they require high computational costs, especially in broadband optimization and system-level designs. This study presents an improved lumped element equivalent circuit topology based on the segmentation principle in transmission line theory, which enables the rapid and accurate modeling of the distributed electromagnetic behavior of physical structures. Within the scope of this study, the performance of different circuit topologies designed in the ADS environment was comparatively analyzed using reference S-parameters obtained with CST Studio Suite. In optimization processes, it has been observed that the physical behavior of fundamental π models is determined by the reflection coefficient (S11), though phase and amplitude errors increase at high frequencies. To overcome this limitation, a final topology was developed by dividing the connecting lines into multiple LC sections and modeling the structural effects. Analysis results show that the Mean Absolute Error value, which was 4.52 dB in the basic models, was reduced to 0.67 dB in the proposed final topology. In particular, the low error rate of 0.64 dB obtained in the transmission characteristic proves that the developed model successfully represents the physical structure over a wide band range. The presented approach combines the accuracy of electromagnetic analysis with the speed of circuit simulation, offering an effective solution for designing complex microwave systems.

Özet

Mikroşerit yönlü kuplörlerin tasarım ve analiz süreçlerinde, tam dalga elektromanyetik benzetimler yüksek doğruluk sağlamaktadır. Ancak özellikle geniş bant optimizasyonu ve sistem seviyesindeki tasarımlarda yüksek hesaplama maliyetleri gerektirmektedir. Bu çalışmada, iletim hattı teorisindeki bölütleme (segmentation) ilkesine dayanan ve fiziksel yapıların dağıtılmış elektromanyetik davranışının hızlı ve doğru bir şekilde modellenmesine olanak tanıyan, geliştirilmiş bir yığılmış eleman eşdeğer devre topolojisi sunulmaktadır. Çalışma kapsamında, ADS ortamında tasarlanan farklı devre topolojilerinin performansları, CST Studio Suite kullanılarak elde edilen referans S-parametreleri ile karşılaştırmalı olarak analiz edilmiştir. Optimizasyon süreçlerinde, temel π modellerinin fiziksel davranışının yansıma katsayısı (S11) tarafından belirlendiği; ancak yüksek frekanslarda faz ve genlik hatalarının arttığı gözlemlenmiştir. Bu sınırlamayı aşmak amacıyla, bağlantı hatlarının birden fazla LC kesitine bölünmesi ve yapısal etkilerin modellenmesiyle nihai bir topoloji geliştirilmiştir. Analiz sonuçları, temel modellerde 4,52 dB olan Ortalama Mutlak Hata (Mean Absolute Error) değerinin, önerilen nihai topolojide 0,67 dB’ye düşürüldüğünü göstermektedir. Özellikle iletim karakteristiğinde elde edilen 0,64 dB’lik düşük hata oranı, geliştirilen modelin fiziksel yapıyı geniş bir bant aralığında başarıyla temsil ettiğini kanıtlamaktadır. Sunulan yaklaşım, elektromanyetik analizlerin doğruluğunu devre benzetimlerinin hızıyla birleştirerek, karmaşık mikrodalga sistemlerinin tasarımı için etkili bir çözüm sunmaktadır.

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Cite This Article

Genç, İ., Gözel, M. A., Kahriman, M. (2026). Development of an Equivalent Circuit Topology for a Directional Coupler. Dicle Üniversitesi Mühendislik Fakültesi Mühendislik Dergisi, Cilt: 17 Sayı: 2. https://doi.org/10.24012/dumf.1884058

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