Design of Microwave Baluns With Flexible Structures

This article presents a design of an unequal termination impedance branch‐line balun with wideband high isolation. The wideband and high isolation characteristics are obtained only in the under‐matched region. For an experimental verification, the proposed balun was designed at a center frequency (f0) of 2.6 GHz. The measured results are in good agreement with the simulations. From the measurement, the power divisions are −3.29 dB and −3.3 dB. The return loss at f0 is 22.3 dB and is higher than 20 dB over a bandwidth of 0.51 GHz. The isolation between output ports is higher than 19 dB for the bandwidth of 0.64 GHz. The phase imbalance between two output ports is 180° ± 5° for the bandwidth of 0.64 GHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1775–1778, 2016

Section: Discussionmentioning

confidence: 99%

“…In Refs. , the branch‐line balun with stubs on its vertical branches could eliminate an unwanted even‐mode signal and reduce the total circuit size. However, the circuit performances had relatively narrow bandwidths and did not consider the isolation between output ports.…”

Section: Introductionmentioning

confidence: 99%

Unequal termination branch‐line balun with high‐isolation wideband characteristics

Kim

Chaudhary

Jeong

2016

“…In addition, matching at the balanced ports and at the input port is also critical . Numerous applications have led to various innovative balun architectures in the last decade . However, most of these designs are either limited in their isolation ability or do not provide output port‐matching simultaneously.…”

Section: Introductionmentioning

confidence: 99%

High impedance transforming simplified Balun architecture in microstrip technology

Gupta

Hashmi

2018

In this article, a simplified balun structure inherently capable of providing high impedance transformation is proposed. The structure fulfills the requirements of a balun such as matching at all the ports, output ports phase difference of 180°, and isolation between output ports. The design is a symmetric network and is able to provide fully closed‐form design equations using the even‐odd mode analysis. The proposed systematic design approach also augments the overall design process. The presence of free variables in design equations provide a number of flexibility to the balun structure including the wide range of impedance transformation ratios of 0.1 to 10.0. A prototype, operating at 1 GHz, on Rogers RT/duroid 5880 substrate demonstrates a very good agreement between the measured and EM simulated results with amplitude and phase imbalance of 1 dB and 10°, respectively.

“…They are widely used in many modern communication system applications such as microwave amplifiers, balanced mixers, frequency multipliers, and balanced antennas . In the past, a number of branch line baluns with size reduction and enhanced bandwidth have been developed for modern communication systems . In , the miniaturized branch line balun with wide bandwidth has been implemented.…”

Section: Introductionmentioning

confidence: 99%

“…A wideband impedance matching network and broadband phase inverter has been used for realization of wideband balun . Transmission lines with arbitrary electrical lengths have been used to construct baluns with flexible structure . Due to the growing demand for a multiband wireless communication system, the design of dual‐band and multiband microwave circuits such as branch line couplers (BLCs), rat‐race couplers (RRCs), and branch line baluns (BLBs) attracts the attention of many researchers.…”

Section: Introductionmentioning

confidence: 99%

Design of a dual‐band microstrip branch‐line balun using T‐shaped coupled lines

Barik

Kumar

Karthikeyan

2017

This article presents the development of a novel dual‐band branch line balun with design flexibility. The T‐shaped coupled line structure is constructed by two series short‐ended coupled lines and one open‐ended stub to obtain the dual‐band characteristics. The proposed dual‐band structure has the capability to design a conventional microstrip line with arbitrary impedances and electrical lengths at two different operating frequencies. In addition to this, different range of frequency ratios is obtained by varying the length of the stub. The required explicit design equations are derived analytically to compute the physical dimensions of the coupled lines and stub. Based on these equations, closely and widely spaced frequency bands useful for many wireless communication systems are devised. To prove better agility, three examples of dual‐band branch line baluns are designed. Finally, a prototype of dual‐band balun is demonstrated for GSM and WiMAX applications at 0.9 and 3.5 GHz, respectively. Good agreement is found between the theoretical predictions and experimental results. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1197–1202, 2017