1,355 research outputs found
Smart Table Based on Metasurface for Wireless Power Transfer
Metasurfaces have been investigated and its numerous exotic functionalities
and the potentials to arbitrarily control of the electromagnetic fields have
been extensively explored. However, only limited types of metasurface have
finally entered into real products. Here, we introduce a concept of a
metasurface-based smart table for wirelessly charging portable devices and
report its first prototype. The proposed metasurface can efficiently transform
evanescent fields into propagating waves which significantly improves the near
field coupling to charge a receiving device arbitrarily placed on its surface
wirelessly through magnetic resonance coupling. In this way, power transfer
efficiency of 80 is experimentally obtained when the receiver is placed at
any distances from the transmitter. The proposed concept enables a variety of
important applications in the fields of consumer electronics, electric
automobiles, implanted medical devices, etc. The further developed
metasurface-based smart table may serve as an ultimate 2-dimensional platform
and support charging multiple receivers.Comment: 8 pages, 7 figure
High Kinetic Inductance Superconducting Nanowire Resonators for Circuit QED in a Magnetic Field
We present superconducting microwave-frequency resonators based on NbTiN
nanowires. The small cross section of the nanowires minimizes vortex
generation, making the resonators resilient to magnetic fields. Measured
intrinsic quality factors exceed in a T in-plane magnetic
field, and in a mT perpendicular magnetic field. Due to
their high characteristic impedance, these resonators are expected to develop
zero-point voltage fluctuations one order of magnitude larger than in standard
coplanar waveguide resonators. These properties make the nanowire resonators
well suited for circuit QED experiments needing strong coupling to quantum
systems with small electric dipole moments and requiring a magnetic field, such
as electrons in single and double quantum dots
Wireless, Customizable Coaxially-shielded Coils for Magnetic Resonance Imaging
Anatomy-specific RF receive coil arrays routinely adopted in magnetic
resonance imaging (MRI) for signal acquisition, are commonly burdened by their
bulky, fixed, and rigid configurations, which may impose patient discomfort,
bothersome positioning, and suboptimal sensitivity in certain situations.
Herein, leveraging coaxial cables' inherent flexibility and electric field
confining property, for the first time, we present wireless, ultra-lightweight,
coaxially-shielded MRI coils achieving a signal-to-noise ratio (SNR) comparable
to or surpassing that of commercially available cutting-edge receive coil
arrays with the potential for improved patient comfort, ease of implementation,
and significantly reduced costs. The proposed coils demonstrate versatility by
functioning both independently in form-fitting configurations, closely adapting
to relatively small anatomical sites, and collectively by inductively coupling
together as metamaterials, allowing for extension of the field-of-view of their
coverage to encompass larger anatomical regions without compromising coil
sensitivity. The wireless, coaxially-shielded MRI coils reported herein pave
the way toward next generation MRI coils
High Impedance Detector Arrays for Magnetic Resonance
Resonant inductive coupling is commonly seen as an undesired fundamental
phenomenon emergent in densely packed resonant structures, such as nuclear
magnetic resonance phased array detectors. The need to mitigate coupling
imposes rigid constraints on the detector design, impeding performance and
limiting the scope of magnetic resonance experiments. Here we introduce a high
impedance detector design, which can cloak itself from electrodynamic
interactions with neighboring elements. We verify experimentally that the high
impedance detectors do not suffer from signal-to-noise degradation mechanisms
observed with traditional low impedance elements. Using this new-found
robustness, we demonstrate an adaptive wearable detector array for magnetic
resonance imaging of the hand. The unique properties of the detector glove
reveal new pathways to study the biomechanics of soft tissues, and exemplify
the enabling potential of high-impedance detectors for a wide range of
demanding applications that are not well suited to traditional coil designs.Comment: 16 pages, 12 figures, videos available upon reques
Planar Microwave Sensors for Accurate Measurement of Material Characterization: A Review
Microwave sensor is used in various industrial applications and requires highly accurate measurements for material properties. Conventionally, cavity waveguide perturbation, free-space transmission, open-ended coaxial probe, and planar transmission line technique have been used for characterizing materials. However, these planar transmission lines are often large and expensive to build, further restricting their use in many important applications. Thus, this technique is cost effective, easy to manufacture and due to its compact size, it has the potential to produce sensitivity and a high Q-factor for various materials. This paper reviews the common characteristics of planar transmission line and discusses numerous studies about several designs of the microstrip resonator to improve the sensor performance in terms of the sensitivity and accuracy. This technique enables its use for several industrial applications such as agriculture and quality control. It is believed that previous studies would lead to a promising solution of characterizing materials with high sensitivity, particularly in determining a high Q-factor resonator sensor
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