University of Twente Student Theses


Investigating Planar Balun Structures with inherent impedance transformation and power combining properties

Daulay, B.Eng O.F.P.G (2018) Investigating Planar Balun Structures with inherent impedance transformation and power combining properties.

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Abstract:In recent years, to accommodate the needs of wireless communication technologies, radio frequency integrated circuits (RFICs) are using differential configurations in their topologies, because they provide better overall RF performance at a relatively low-cost increment. However, the growth number of portable devices, embedded systems, and Internet of Things (IoT) applications mean that there are a large number of demands for small/tiny, low-power baluns. Moreover, for flexibility and cost reasons, planar versions of balun structures are needed. The goal of this research is to investigate whether a balanced-to-unbalanced (balun) structure can simultaneously be used for impedance transformation and power combination as well. As a result, this research presents the planar version of a 1:4 Guanella balun, a 1:4 Ruthroff balun, and a 1:4 Differential balun. Three proposed structures are implemented at a center frequency of 1.5 GHz. These baluns work as matching networks and power combining between single ended and differential ports. All these balun structures are designed and simulated with Advanced Design System (ADS) from Keysight. For measurement purposes, all structures were fabricated on 0.5 mm printed circuit board (PCB) with I-tera substrate (!! = 3.38 and !"#$ = 0.0028). Based on measurement results, the 1:4 Guanella balun has the biggest fractional bandwidth (FBW) of 175 %. Next, the 1:4 Ruthroff balun comes second with FBW of 85 %. Last, the 1:4 Differential balun has the smallest FBW of 19 %. The results show that planar 1:4 Guanella balun, planar 1:4 Ruthroff balun, and planar 1:4 differential balun can be used in many wireless communication devices for portable devices, embedded systems, and IoT.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:01 general works, 33 physics, 50 technical science in general, 53 electrotechnology
Programme:Embedded Systems MSc (60331)
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