Impedance tuner using BST varactors in alumina-based IPD technology

Wong, Ka Wai; Mansour, Raafat R.

doi:10.1109/eumc.2016.7824527

Cited by 9 publications

(2 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The minimal measured Smith-chart coverage is 70% and its VSWR CC is 3.4 in the whole 1.4-3.2 GHz frequency band (85% FBW), and VSWR CC > 6.2 for the 2-3.2 GHz frequency band. The Smith-chart coverage, VSWR CC , and FBW of the proposed TLM tuner exceed those reported in [1][2][3][4][5]. It features a size of 0.13λ × 0.039λ, which is similar to that of the lumped-element tuner in [5] (0.08λ × 0.044λ), but smaller than that of the distributed-element tuners [1] (0.56λ × 0.307λ) and [4] (0.25λ × 0.25λ).…”

Section: Fig 1 Tlm Impedance Tuner Structurecontrasting

confidence: 53%

“…In [4] a small‐size, low‐power‐consumption tuner for RFID applications using varactors is proposed featuring a 50% FBW (1.8–3 GHz), moderate (an estimated 64.3%) Smith‐chart coverage, with complete coverage of all reflection coefficients with voltage standing‐wave ratio (VSWR) lower than VSWR CC = 4.6 (and any phase) at 2.2 GHz. The integrated‐passive device tuner using ferroelectric varactors in [5] features small size, and a 40% FBW (2–3 GHz) for an estimated 40% Smith‐chart coverage and VSWR CC = 1.8. In [1] a substrate‐integrated‐cavity technology with piezoelectric actuated dishes is used to achieve a 37% FBW (2.5–3.9 GHz) with a 50% Smith‐chart coverage, and VSWR CC = 2 in the 2.53.7 GHz frequency range.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Compact, wideband impedance tuner using a three‐line‐microstrip structure

2018

View full text Add to dashboard Cite

A novel three-line-microstrip compact impedance tuner is presented. It is based on a multimodal structure wherein six variable capacitances, implemented with two parallel-connected varactors each, create multiple interactions among the three-line-microstrip modes in a reduced circuit area. Experimental results show better-than-70% coverage of the Smith chart in an 85% frequency bandwidth from 1.4 to 3.2 GHz.Introduction: Impedance tuners are extensively used to implement tunable matching networks in power amplifiers [1] or antennas [2], and for load-pull or noise-parameter characterisation [3]. To provide flexibility in reconfigurable systems, the tuner should be compact in size, with a wide Smith-chart coverage and large fractional frequency bandwidth (FBW). Recent MOS and BiCMOS mm-wave tuners [2,3] exhibit a very small area, but limited (an estimated 35%) Smith-chart coverage. In [4] a small-size, low-power-consumption tuner for RFID applications using varactors is proposed featuring a 50% FBW (1.8-3 GHz), moderate (an estimated 64.3%) Smith-chart coverage, with complete coverage of all reflection coefficients with voltage standing-wave ratio (VSWR) lower than VSWR CC = 4.6 (and any phase) at 2.2 GHz. The integrated-passive device tuner using ferroelectric varactors in [5] features small size, and a 40% FBW (2-3 GHz) for an estimated 40% Smith-chart coverage and VSWR CC = 1.8. In [1] a substrate-integrated-cavity technology with piezoelectric actuated dishes is used to achieve a 37% FBW (2.5-3.9 GHz) with a 50% Smith-chart coverage, and VSWR CC = 2 in the 2.53.7 GHz frequency range.Multimodal circuits use multimodal waveguides to allow the propagation of more than one fundamental mode in the same circuit area. The additional modes increase the equivalent electrical length of the circuit, allowing for designs that are more compact. Multimodal circuits have demonstrated compact size and reconfiguration capabilities in structures such as filters [6].In this Letter, a novel varactor-loaded multimodal threeline-microstrip (TLM) structure is used to implement a wideband impedance tuner with a wide, uniform Smith-chart coverage in the whole operation band.

show abstract

Section: Fig 1 Tlm Impedance Tuner Structurecontrasting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Compact, wideband impedance tuner using a three‐line‐microstrip structure

2018

View full text Add to dashboard Cite

show abstract

Repetitive ultramicrotome trimming and SEM imaging for characterizing printed multilayer structures

Huang,

Mach,

Binder

et al. 2024

Sci Rep

View full text Add to dashboard Cite

Ultramicrotomy is a well-established technique that has been applied in biology and medical research to produce thin sections or a blockface of an embedded sample for microscopy. Recently, this technique has also been applied in materials science or micro- and nanotechnology as a sample preparation method for subsequent characterization. In this work, an application of ultramicrotomy for the cross-section preparation of an inkjet-printed multilayer structure is demonstrated. The investigated device is a capacitor consisting of three layers. The top and bottom electrodes are printed with silver nanoparticle ink and the dielectric layer with a ceramic nanoparticle/polymer ink. A 3D profilometer is initially used to study the surface morphology of the printed multilayer. The measurements show that both electrodes exhibit a coffee-ring effect, which results in an inhomogeneous layer structure of the device. To obtain precise 3D information on the multilayer, cross-sections must be prepared. Argon ion beam milling is the current gold standard to produce a single cross-section in good quality, however, the cross-section position within the multilayer volume is poorly defined. Moreover, the milling process requires a significant investment of time and resources. Herein, we develop an efficient method to realize repetitive cross-section preparation at well-defined positions in the multilayer volume. Repetitive cross-sections are exposed by trimming with an ultramicrotome (UM) and this blockface is subsequently transferred into a scanning electron microscope (SEM) for imaging. A combination of custom-modified UM and SEM specimen holders allows repeated transfer of the clamped multilayer sample between instruments without damage and with high positioning accuracy. This novel approach enhances the combination of an established ultramicrotome and a SEM for multilayer sample volume investigation. Thus, a comprehensive understanding of printed multilayer structures can be gained, to derive insights for optimization of device architecture and printing process.

show abstract