Hybrid‐pair ratio adjustable power splitters for add‐on RF shimming and array‐compressed parallel transmission

2021 ◽  
Author(s):  
Yue Zhu ◽  
Ming Lu ◽  
William A. Grissom ◽  
John C. Gore ◽  
Xinqiang Yan
Keyword(s):  
Parallel Transmission ◽  
Rf Shimming ◽  
Power Splitters ◽  
Hybrid Pair

scholarly journals Ratio‐adjustable power splitters for array‐compressed parallel transmission

2017 ◽  
Vol 79 (4) ◽  
pp. 2422-2431 ◽  
Author(s):  
Xinqiang Yan ◽  
Zhipeng Cao ◽  
William A. Grissom
Keyword(s):  
Parallel Transmission ◽  
Power Splitters

scholarly journals Extended RF shimming: Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart

2017 ◽  
Vol 30 (6) ◽  
pp. e3701 ◽  
Author(s):  
Arian Beqiri ◽  
Anthony N. Price ◽  
Francesco Padormo ◽  
Joseph V. Hajnal ◽  
Shaihan J. Malik
Keyword(s):  
Steady State ◽  
Steady State Free Precession ◽  
Free Precession ◽  
Parallel Transmission ◽  
Rf Shimming

A phasor-distance based faulty phase detection and fault classification technique for parallel transmission lines

2020 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kothari ◽  
Bhavesh R. Bhalja ◽  
Vivek Pandya ◽  
Pushkar Tripathi ◽  
Soumitri Jena
Keyword(s):  
Transmission Lines ◽  
Power Flow ◽  
Detection Algorithm ◽  
Current Transformer ◽  
Operating Conditions ◽  
Fault Classification ◽  
Phase Detection ◽  
Parallel Transmission ◽  
Classification Technique ◽  
Computational Requirement

AbstractThis paper presents a phasor-distance based faulty phase detection and fault classification technique for parallel transmission lines. Detection and classification of faulty phase(s) have been carried out by deriving indices from the change in phasor values of current with a distance of one cycle. The derived indices have zero values during normal operating conditions whereas the index corresponding to the faulty phase exceeds the pre-defined threshold in case of occurrence of a fault. A separate ground detection algorithm has been utilized for the identification of involvement of ground in a faulty situation. The performance of the proposed technique has been evaluated for intra-circuit, inter-circuit and simultaneous faults with wide variations in system and fault conditions. The suggested technique has been evaluated for over 23,000 diversified simulated fault cases as well as 14 recorded real fault events. The performance of the proposed technique remains consistent under Current Transformer (CT) saturation as well as different amount and direction of power flow. Moreover, suitability to different power system network has also been studied. Also, faults having fault current less than pre-fault conditions have been detected accurately. The results obtained suggest that it is able to detect faulty phases as well as classify faults within quarter-cycle from the inception of fault with impeccable accuracy. Besides, as modern digital relays have been already equipped with phasor computation facility, phasor-based technique can be easily incorporated with relative ease. At last, a comparative evaluation suggests its superiority in terms of fault classification accuracy, fault detection time, diversify fault scenarios and computational requirement among other existing techniques.

scholarly journals High-Performance On-Chip Silicon Beamsplitter Based on Subwavelength Metamaterials for Enhanced Fabrication Tolerance

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1304
Author(s):  
Raquel Fernández de Cabo ◽  
David González-Andrade ◽  
Pavel Cheben ◽  
Aitor V. Velasco
Keyword(s):  
Integrated Circuits ◽  
Fundamental Mode ◽  
High Performance ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Power Splitting ◽  
Excess Loss ◽  
Power Splitters ◽  
On Chip ◽  
Efficient Power

Efficient power splitting is a fundamental functionality in silicon photonic integrated circuits, but state-of-the-art power-division architectures are hampered by limited operational bandwidth, high sensitivity to fabrication errors or large footprints. In particular, traditional Y-junction power splitters suffer from fundamental mode losses due to limited fabrication resolution near the junction tip. In order to circumvent this limitation, we propose a new type of high-performance Y-junction power splitter that incorporates subwavelength metamaterials. Full three-dimensional simulations show a fundamental mode excess loss below 0.1 dB in an ultra-broad bandwidth of 300 nm (1400–1700 nm) when optimized for a fabrication resolution of 50 nm, and under 0.3 dB in a 350 nm extended bandwidth (1350–1700 nm) for a 100 nm resolution. Moreover, analysis of fabrication tolerances shows robust operation for the fundamental mode to etching errors up to ± 20 nm. A proof-of-concept device provides an initial validation of its operation principle, showing experimental excess losses lower than 0.2 dB in a 195 nm bandwidth for the best-case resolution scenario (i.e., 50 nm).

scholarly journals Common fixed points of single-valued and multivalued maps

2005 ◽  
Vol 2005 (19) ◽  
pp. 3045-3055 ◽  
Author(s):  
Yicheng Liu ◽  
Jun Wu ◽  
Zhixiang Li
Keyword(s):  
Fixed Point ◽  
Fixed Points ◽  
Common Fixed Point ◽  
Fixed Point Theorems ◽  
Common Fixed Points ◽  
Partial Answer ◽  
Multivalued Maps ◽  
Hybrid Pair ◽  
Common Fixed Point Theorems

We define a new property which contains the property (EA) for a hybrid pair of single- and multivalued maps and give some new common fixed point theorems under hybrid contractive conditions. Our results extend previous ones. As an application, we give a partial answer to the problem raised by Singh and Mishra.

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