An analysis to predict the optimal physical length of the coupled lines of a Transformer balun

Nethini Weerathunge; Sudipta Chakraborty; Simon J. Mahon; Melissa C. Gorman

doi:10.23919/EuMC65286.2025.11234986

An analysis to predict the optimal physical length of the coupled lines of a Transformer balun

Nethini Weerathunge, Sudipta Chakraborty, Simon J. Mahon, Melissa C. Gorman

School of Engineering

Research output: Chapter in Book/Report/Conference proceeding › Conference proceeding contribution › peer-review

Abstract

An analysis is presented for the first time to predict the optimal physical length of the coupled lines to implement a Transformer balun at a given center frequency. The impact of the coupling coefficient on the physical length of the coupled lines, the balun's bandwidth, and its insertion loss is also discussed. A Transformer balun is implemented in the WIN Semiconductors' 0.15 μm GaN process to validate the observations from the analysis. The measured 3 dB bandwidth of the balun is between 24 GHz - 40.4 GHz. The minimum insertion loss of 0.3 dB is measured close to the center frequency of the Ka-band. The measured magnitude and phase imbalances are 0.5 dB and 0.5 º respectively.

Original language	English
Title of host publication	2025 55th European Microwave Conference (EuMC)
Place of Publication	Piscataway, NJ
Publisher	Institute of Electrical and Electronics Engineers (IEEE)
Pages	447-450
Number of pages	4
ISBN (Electronic)	9782874870811
ISBN (Print)	9798331512606
DOIs	https://doi.org/10.23919/EuMC65286.2025.11234986
Publication status	Published - 2025
Event	55th European Microwave Conference, EuMC 2025 - Utrecht, Netherlands Duration: 23 Sept 2025 → 25 Sept 2025

Conference

Conference	55th European Microwave Conference, EuMC 2025
Country/Territory	Netherlands
City	Utrecht
Period	23/09/25 → 25/09/25

Bibliographical note

Alternative title of the host publication: "Proceedings of the 55th European Microwave Conference"

Keywords

Transformer balun
Marchand balun
coupling coefficient
coupled lines
S-parameters
bandwidth
insertion loss

Access to Document

10.23919/EuMC65286.2025.11234986

Cite this

@inproceedings{024f429c684d45d99bf11cade5425609,

title = "An analysis to predict the optimal physical length of the coupled lines of a Transformer balun",

abstract = "An analysis is presented for the first time to predict the optimal physical length of the coupled lines to implement a Transformer balun at a given center frequency. The impact of the coupling coefficient on the physical length of the coupled lines, the balun's bandwidth, and its insertion loss is also discussed. A Transformer balun is implemented in the WIN Semiconductors' 0.15 μm GaN process to validate the observations from the analysis. The measured 3 dB bandwidth of the balun is between 24 GHz - 40.4 GHz. The minimum insertion loss of 0.3 dB is measured close to the center frequency of the Ka-band. The measured magnitude and phase imbalances are 0.5 dB and 0.5 º respectively.",

keywords = "Transformer balun, Marchand balun, coupling coefficient, coupled lines, S-parameters, bandwidth, insertion loss",

author = "Nethini Weerathunge and Sudipta Chakraborty and Mahon, \{Simon J.\} and Gorman, \{Melissa C.\}",

note = "Alternative title of the host publication: {"}Proceedings of the 55th European Microwave Conference{"}; 55th European Microwave Conference, EuMC 2025 ; Conference date: 23-09-2025 Through 25-09-2025",

year = "2025",

doi = "10.23919/EuMC65286.2025.11234986",

language = "English",

isbn = "9798331512606",

pages = "447--450",

booktitle = "2025 55th European Microwave Conference (EuMC)",

publisher = "Institute of Electrical and Electronics Engineers (IEEE)",

address = "United States",

}

Weerathunge, N, Chakraborty, S , Mahon, SJ & Gorman, MC 2025, An analysis to predict the optimal physical length of the coupled lines of a Transformer balun. in 2025 55th European Microwave Conference (EuMC). Institute of Electrical and Electronics Engineers (IEEE), Piscataway, NJ, pp. 447-450, 55th European Microwave Conference, EuMC 2025, Utrecht, Netherlands, 23/09/25. https://doi.org/10.23919/EuMC65286.2025.11234986

An analysis to predict the optimal physical length of the coupled lines of a Transformer balun. / Weerathunge, Nethini; Chakraborty, Sudipta ; Mahon, Simon J. et al.
2025 55th European Microwave Conference (EuMC). Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2025. p. 447-450.

Research output: Chapter in Book/Report/Conference proceeding › Conference proceeding contribution › peer-review

TY - GEN

T1 - An analysis to predict the optimal physical length of the coupled lines of a Transformer balun

AU - Weerathunge, Nethini

AU - Chakraborty, Sudipta

AU - Mahon, Simon J.

AU - Gorman, Melissa C.

N1 - Alternative title of the host publication: "Proceedings of the 55th European Microwave Conference"

PY - 2025

Y1 - 2025

N2 - An analysis is presented for the first time to predict the optimal physical length of the coupled lines to implement a Transformer balun at a given center frequency. The impact of the coupling coefficient on the physical length of the coupled lines, the balun's bandwidth, and its insertion loss is also discussed. A Transformer balun is implemented in the WIN Semiconductors' 0.15 μm GaN process to validate the observations from the analysis. The measured 3 dB bandwidth of the balun is between 24 GHz - 40.4 GHz. The minimum insertion loss of 0.3 dB is measured close to the center frequency of the Ka-band. The measured magnitude and phase imbalances are 0.5 dB and 0.5 º respectively.

AB - An analysis is presented for the first time to predict the optimal physical length of the coupled lines to implement a Transformer balun at a given center frequency. The impact of the coupling coefficient on the physical length of the coupled lines, the balun's bandwidth, and its insertion loss is also discussed. A Transformer balun is implemented in the WIN Semiconductors' 0.15 μm GaN process to validate the observations from the analysis. The measured 3 dB bandwidth of the balun is between 24 GHz - 40.4 GHz. The minimum insertion loss of 0.3 dB is measured close to the center frequency of the Ka-band. The measured magnitude and phase imbalances are 0.5 dB and 0.5 º respectively.

KW - Transformer balun

KW - Marchand balun

KW - coupling coefficient

KW - coupled lines

KW - S-parameters

KW - bandwidth

KW - insertion loss

UR - https://www.scopus.com/pages/publications/105029554803

U2 - 10.23919/EuMC65286.2025.11234986

DO - 10.23919/EuMC65286.2025.11234986

M3 - Conference proceeding contribution

AN - SCOPUS:105029554803

SN - 9798331512606

SP - 447

EP - 450

BT - 2025 55th European Microwave Conference (EuMC)

PB - Institute of Electrical and Electronics Engineers (IEEE)

CY - Piscataway, NJ

T2 - 55th European Microwave Conference, EuMC 2025

Y2 - 23 September 2025 through 25 September 2025

ER -

An analysis to predict the optimal physical length of the coupled lines of a Transformer balun

Abstract

Conference

Bibliographical note

Keywords

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