A Broad-Band Quarter-Wavelength Impedance Transformer With Three Reflection Zeros Within Passband

Ang, Kian Siong; Lee, Chee How; Leong, Yoke Choy

doi:10.1109/tmtt.2004.837310

Cited by 38 publications

(29 citation statements)

References 9 publications

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“…The implementation method for impedance transformer by using coupled transmission lines has also attracted the attention of many researchers [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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A Novel Compact Dual-Frequency Coupled-Line Transformer With Simple Analytical Design Equations for Frequency-Dependent Complex Load Impedance

Wu¹,

Sun²,

Leung³

et al. 2013

PIER

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Abstract-In order to perfectly match arbitrary frequency-dependent complex load impedances at two uncorrelated frequencies, a novel coupled-line impedance transformer without transmission-line stubs is proposed in this paper. This transformer mainly features small size, wide bandwidth, simple analytical design method, and easy planar implementation. The transformer simply consists of a coupledline section and an additional transmission-line section. Due to the usage of a coupled-line section, the theoretical synthesis of the proposed transformer becomes very simple when compared with previous transformers and the total size of the planar circuit without deterioration of operating bandwidth becomes small. Furthermore, several numerical examples are presented to demonstrate the flexible dual-frequency matching performance. Finally, the profile of matching frequency-dependent complex load impedance at two arbitrary frequencies has been examined by simulation and measurement of two microstrip generalized T -junction power dividers. Good agreement between the calculated results and measured ones justifies this proposed transformer and the design theory.

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“…The implementation method for impedance transformer by using coupled transmission lines has also attracted the attention of many researchers [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…In [13], a broad-band quarter-wavelength impedance transformer has been proposed. The required evenand odd-mode impedance of coupled lines cannot be easily realized in microstrip technology.…”

Section: Introductionmentioning

confidence: 99%

A Novel Compact Dual-Frequency Coupled-Line Transformer With Simple Analytical Design Equations for Frequency-Dependent Complex Load Impedance

Wu¹,

Sun²,

Leung³

et al. 2013

PIER

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“…Indeed, a conventional quarter-wavelength transformer is a well-known IT [4], but this network has some limitations, such as difficulty in the realization of a high impedance transforming ratio and poor out-of-band suppression. In recent years, various structures of filtering IT have been proposed [5][6][7][8][9][10][11]. A mixed lumped and distributed IT with low-pass filtering response is designed in [5].…”

Section: Introductionmentioning

confidence: 99%

“…However, the shunt capacitors can produce a self-resonance frequency, which introduces additional parasitic effects at high frequency. Wideband ITs are proposed using an open-circuit parallel-coupled line with an interconnecting transmission line (TL) [6] and a multiple-section stepped-impedance TL with input/output couplings [7]. However, their impedance transforming ratio is low.…”

Section: Introductionmentioning

confidence: 99%

A Coupled Line Impedance Transformer for High Termination Impedance with a Bandpass Filtering Response

Kim

Jeong

2018

J Electromagn Eng Sci

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In this study, a short-ended coupled line with a short-circuit stub transmission line bandpass filtering impedance transformer is presented. The general designed equations are derived on the basis of circuit theory. The design curves are provided to examine the characteristic of the proposed impedance transformer. The proposed circuit is suitable for high termination impedance. To validate the design formulas, a 400-50 Ω impedance transformer is designed and fabricated at the operating center frequency (f0) of 2.6 GHz. The measured results show a good agreement with the simulation. The measured insertion and return losses are 0.6 dB and 22.5 dB at f0, respectively. The measured return loss is higher than 20 dB within the passband frequency of 2.51-2.7 GHz. Moreover, the stopband attenuation is higher than 25 dB from DC to 1.64 GHz of the lower stopband and from 3.12 GHz to 6.4 GHz of the higher stopband. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ⓒ

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“…Recently, coupled transmission lines have been developed for impedance transformers [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

A Novel High-Power Amplifier Using a Generalized Coupled-Line Transformer With Inherent Dc-Block Function

Wu¹,

Liu²,

Li³

et al. 2011

PIER

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Abstract-The purpose of this paper is to propose a novel generalized single-band transformer for two arbitrary complex load and source impedances and a novel high-power amplifier using this new transformer. By adding two reactive parts at across terminals, the coupled line with flexible electrical length has practical evenand odd-mode characteristic impedances. Thus, the total circuit layout can be realized on common printed circuit board without any restriction. The synthesis theory of this proposed transformer is complete and analytical. Furthermore, unlike conventional quarterwavelength transformers, this structure exhibits four main features such as effective matching for extremely low-resistive load impedance, effective matching for extremely high-resistive load impedance, tunable characteristic for equivalent electrical length and inherent DC-block function. For theoretical verification, several impedance transformers, which include some fixed operating-frequency cases and a tunable case, for smaller than 7 Ohm or larger than 1500 Ohm, are presented. As a typical experimental example, this analyzed transformer with inherent DC-block function has been applied in a 4-Watt power amplifier as output matching structure.

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A Broad-Band Quarter-Wavelength Impedance Transformer With Three Reflection Zeros Within Passband

Cited by 38 publications

References 9 publications

A Novel Compact Dual-Frequency Coupled-Line Transformer With Simple Analytical Design Equations for Frequency-Dependent Complex Load Impedance

A Novel Compact Dual-Frequency Coupled-Line Transformer With Simple Analytical Design Equations for Frequency-Dependent Complex Load Impedance

A Coupled Line Impedance Transformer for High Termination Impedance with a Bandpass Filtering Response

A Novel High-Power Amplifier Using a Generalized Coupled-Line Transformer With Inherent Dc-Block Function

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