A new strategy to reduce edge chipping using stress wave impedance matching

CIRP Annals ◽  
2021 ◽  
Author(s):  
Yifan Zhang ◽  
Yuyang Zhao ◽  
Jundong Xu ◽  
Mengqi Rao ◽  
Yuehong Yin
Author(s):  
K. Parow-Souchon ◽  
D. Cuadrado-Calle ◽  
S. Rea ◽  
M. Henry ◽  
M. Merritt ◽  
...  

Abstract Realizing packaged state-of-the-art performance of monolithic microwave integrated circuits (MMICs) operating at millimeter wavelengths presents significant challenges in terms of electrical interface circuitry and physical construction. For instance, even with the aid of modern electromagnetic simulation tools, modeling the interaction between the MMIC and its package embedding circuit can lack the necessary precision to achieve optimum device performance. Physical implementation also introduces inaccuracies and requires iterative interface component substitution that can produce variable results, is invasive and risks damaging the MMIC. This paper describes a novel method for in situ optimization of packaged millimeter-wave devices using a pulsed ultraviolet laser to remove pre-selected areas of interface circuit metallization. The method was successfully demonstrated through the optimization of a 183 GHz low noise amplifier destined for use on the MetOp-SG meteorological satellite series. An improvement in amplifier output return loss from an average of 12.9 dB to 22.7 dB was achieved across an operational frequency range of 175–191 GHz and the improved circuit reproduced. We believe that our in situ tuning technique can be applied more widely to planar millimeter-wave interface circuits that are critical in achieving optimum device performance.


Author(s):  
Mohamed Ribate ◽  
Rachid Mandry ◽  
Jamal Zbitou ◽  
Larbi El Abdellaoui ◽  
Ahmed Errkik ◽  
...  

In this paper, the design of a Broadband Power Amplifier for UHF applications is presented. The proposed BPA is based on ATF13876 Agilent active device. The biasing and matching networks both are implemented by using microstrip transmission lines. The input and output matching circuits are designed by combining two broadband matching techniques: a binomial multi-section quarter wave impedance transformer and an approximate transformation of previously designed lumped elements. The proposed BPA shows excellent performances in terms of impedance matching, power gain and unconditionally stability over the operating bandwidth ranging from 1.2 GHz to 3.3 GHz. At 2.2 GHz, the large signal simulation shows a saturated output power of 18.875 dBm with an output 1-dB compression point of 6.5 dBm of input level and a maximum PAE of 36.26%.


2019 ◽  
Vol 6 ◽  
pp. 21
Author(s):  
Takuya Yamaguchi ◽  
Takumi Ishiyama ◽  
Tetsuya Ueda ◽  
Tatsuo Itoh

In this paper, we consider cube-shaped unit cells including high-ε dielectric cubes under magnetic dipole-like resonance placed at the center and metallic mesh wires for negative permittivity to construct three-dimensional quasi-isotropic metamaterials in the microwave region. Basically, such structures suffer from their low wave impedance due to inclusion of high-ε materials. To reduce effective permittivity of the composite structures, we propose to insert additional inductance into the metallic mesh. For the insertion of lumped inductors along the wires, dispersion diagram and the Bloch-impedance are numerically estimated, and converted to effective permittivity and permeability. The numerical simulation results clearly show almost 3-D isotropic propagation characteristics in a specific frequency region and enhancement of the Bloch-impedance close to free space in the left-handed region. The lumped inductors are replaced by meander-line strip patterns for practical configurations. The metallic patterned structures also achieve the enhanced Bloch impedance that is well-matched to free space.


Author(s):  
Wanyi Du ◽  
Yuanyuan Huang ◽  
Yixuan Zhou ◽  
Xinlong Xu

Abstract Terahertz (THz) interface physics as a new interdiscipline between THz technique and condensed matter physics has undergone rapid developments in recent years. Especially, the developments of advanced materials, such as graphene, transitional metal dichalcogenides, topological insulators, ferromagnetic metals, and metamaterials, have revolutionized the interface field and further promotes the development of THz functional devices based on interface physics. Moreover, playing at the interface with these advanced materials could unveil a wealth of fascinating physical effects such as charge transfer, proximity effect, inverse spin-Hall effect, and Rashba effect with THz technology by engineering the charge, spin, orbit, valley, and lattice degrees of freedom. In this review, we start from the discussion of the basic theory of THz interface physics, including interface formation with advanced materials, THz wave reflection and transmission at the interface, and band alignment and charge dynamics at the interface. Then we move to recent progresses in advanced materials from THz wave propagation to THz wave generation at the interface. In the THz wave propagation, we focus on the THz wave impedance-matching, Goos–Hänchen and Imbert–Fedorov shifts in THz region, interfacial modulation and interfacial sensing based on THz wave. In the THz wave generation, we summarize the ongoing coherent THz wave generation from van der Waals interfaces, multiferroic interfaces, and magnetic interfaces. The fascinating THz interface physics in advanced materials is promising and promoting novel THz functional devices for manipulating the propagation and generation of THz wave at the interfaces.


2007 ◽  
Vol 15 (11) ◽  
pp. 6552 ◽  
Author(s):  
Josef Kröll ◽  
Juraj Darmo ◽  
Karl Unterrainer

2015 ◽  
Vol 3 (11) ◽  
pp. 2548-2556 ◽  
Author(s):  
Yixuan Zhou ◽  
Yiwen E ◽  
Zhaoyu Ren ◽  
Haiming Fan ◽  
Xinlong Xu ◽  
...  

The potential of solution-processable reduced graphene oxide (rGO) films as wave impedance matching layers has been examined in a broad terahertz (THz) spectral bandwidth.


2011 ◽  
Vol 130-134 ◽  
pp. 1775-1778
Author(s):  
Jun Li ◽  
Quan Li Ning ◽  
Chuang Liu

Taking aim at the phenomenon that the propagation process of one-dimensional stress wave in projectile will be exposed to reflection and transmission on the interface between mediums, based on wave impedance and limit yield of the different mediums inside some type projectile, using calculation and graphic method, analyses one-dimensional stress wave propagation in different mediums, educe ultimate loading action on projectile-loaded equipment.


Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1114
Author(s):  
Yosef T. Aladadi ◽  
Majeed A. S. Alkanhal

This paper presents a full electromagnetic (EM) characterization of metallic lenses. The method is based on the utilization of free-space transmission and reflection coefficients to accurately obtain lenses’ tensorial EM parameters. The applied method reveals a clear anisotropic behavior with a full tensorial directional permittivity and permeability and noticeably dispersive permeability and wave impedance. This method yields accurate values for the effective refractive index, wave impedance, permittivity, and permeability, unlike those obtained by simple methods such as the eigenmode method. These correct cell parameters affect their lens performance, as manifested in a clear level of anisotropy, impedance matching, and losses. The effect of anisotropy caused by oblique incidence on the performance and operation of lens designs is illustrated in a lens design case.


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