scholarly journals Magnetic-Free Isolators Based on Time-Varying Transmission Lines

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 684 ◽  
Author(s):  
Fengchuan Wu ◽  
Yuejun Zheng ◽  
Fang Yuan ◽  
Yunqi Fu
Keyword(s):  
Transmission Lines ◽  
Reverse Direction ◽  
Time Varying ◽  
Power Capacity ◽  
Line Segments ◽  
Control Signals ◽  
Higher Power ◽  
Power Splitters ◽  
Differential Transmission ◽  
Reverse Signal

Two magnetic-free reconfigurable isolators based on a doubly balanced gyrator (DBG) are designed in this paper. One of the isolators is a single-ended transmission isolator (STI), which uses two matching resistors to absorb the signal transmitted in the reverse direction. In theory, it has infinite isolation bandwidth, which is verified by simulation and an experiment. The other isolator is a differential transmission isolator (DTI) to improve the anti-interference performance, which consists of four Wilkinson power splitters (combiners) and two reciprocal transmission line segments. The DTI uses two pairs of differential signals to prevent the reverse signal. Compared to the STI, the DTI has higher power capacity. Furthermore, when the phases of the control signals acting on the switches are changed, the isolation directions of the two isolators will be changed, to obtain the reconfigurable property.

scholarly journals Magnetic-Free Nonreciprocal Multifunction Device Based on Switched Delay Lines

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 862
Author(s):  
Fengchuan Wu ◽  
Yuejun Zheng ◽  
Yunqi Fu
Keyword(s):  
Transmission Line ◽  
Time Reversal ◽  
Time Reversal Symmetry ◽  
Delay Lines ◽  
Power Capacity ◽  
Common Mode ◽  
Control Signals ◽  
Differential Transmission ◽  
The Asymmetry ◽  
Mode Interference

A magnetic-free multifunction nonreciprocal device based on switched delay lines (SDLs) has been proposed in this paper. It is constructed with two double balanced gyrators (DBGs) and four baluns, each pair of differential ports of the balun connect the ports at the same orientation of the two DBGs, respectively. Due to the asymmetry of the clock control signals acting on the switches, the time reversal symmetry of the transmission line between the Gilbert quad-switch-sets (GQSS) can be broken to achieve non-reciprocity. It can be used as a circulator, gyrator, or isolator by setting different control signals. The device has infinite working bandwidth in theory based on the SDLs. Common mode interference can be better suppressed by using differential transmission structures. Moreover, power capacity can be improved compared to the previous work. Then, experiments have been done to verify the device as a circulator. Broadband property and the anti-interference property have been verified.

Reducing glitches when reconstructing four-port S-parameters of differential transmission lines from two-port measurements

2014 ◽  
Vol 56 (10) ◽  
pp. 2257-2260 ◽  
Author(s):  
Daniel M. García-Mora ◽  
Miguel A. Tlaxcalteco-Matus ◽  
Reydezel Torres-Torres ◽  
Gaudencio Hernández-Sosa ◽  
Olga M. Becerra-Fuentes
Keyword(s):  
Transmission Lines ◽  
S Parameters ◽  
Differential Transmission

scholarly journals Comparative Study of Stabilization Controls of a Forklift Vehicle

2019 ◽  
Vol 13 (3) ◽  
pp. 181-188
Author(s):  
Augie Widyotriatmo
Keyword(s):  
Control Algorithm ◽  
Blow Up ◽  
Point Of View ◽  
Time Varying ◽  
Discontinuous Control ◽  
Slow Convergence ◽  
Practical Point ◽  
Final Configuration ◽  
Control Signals ◽  
Control Designs

Abstract This paper presents the control designs for an autonomous forklift vehicle that drive the vehicle from an initial configuration to a final one. Three stabilization controls, which are chained-form time-varying control, sigma-transformed discontinuous control, and navigation-variables-based discontinuous control, for a forklift vehicle are compared by simulations. The sigma-transformed and navigation-variables-based discontinuous controls provide fast convergence motions from an initial to a final configuration, while the time-varying-based control provides oscillatory motion and slow convergence. The sigma-transformed discontinuous control has a set of discontinuous points in which, from a practical point of view, the control signals can blow up if a vehicle enters the set. The navigation-variables-based control, which also has a discontinuous point at the final configuration, does not produce blown up control signals since its boundedness nature. Discussion on the implementation of control algorithm is elucidated for the three stabilization controls for the forklift vehicle.

Reactively-loaded non-periodic slow-wave artificial transmission lines for stop band bandwidth enhancement: application to power splitters

2019 ◽  
Vol 11 (5-6) ◽  
pp. 475-481 ◽  
Author(s):  
Jan Coromina ◽  
Paris Vélez ◽  
Jordi Bonache ◽  
Francisco Aznar-Ballesta ◽  
Armando Fernández-Prieto ◽  
...  
Keyword(s):  
Slow Wave ◽  
Transmission Lines ◽  
Periodic Structures ◽  
Characteristic Impedance ◽  
Stop Band ◽  
Pass Band ◽  
Harmonic Suppression ◽  
Transmission Zeros ◽  
Rejection Level ◽  
Power Splitters

AbstractThis paper presents slow-wave transmission lines based on non-periodic reactive loading. Specifically, the loading elements are stepped impedance shunt stubs (SISS). By sacrificing periodicity using SISS tuned to different frequencies, multiple transmission zeros above the pass band arise, and the rejection level and bandwidth of the stop band is improved as compared with those of periodic structures. Through a proper design, it is possible to achieve compact lines, simultaneously providing the required electrical length and characteristic impedance at the design frequency (dictated by specifications), and efficiently filtering the response at higher frequencies. These lines are applied to the design of a compact power splitter with filtering capability in this work. The length of the splitter, based on a 35.35 Ω impedance inverter, is reduced by a factor of roughly two. Moreover, harmonic suppression better than 20 dB up to the fourth harmonic is achieved.

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