Influence of mode-mismatching on total phase shift of wave in cavity

Author(s):  
K.I. Muntean ◽  
V.A. Svich
Keyword(s):  
2011 ◽  
Vol 403-408 ◽  
pp. 4179-4183
Author(s):  
Anesh K. Sharma ◽  
Ashu K. Gautam ◽  
D.V.K. Sastry ◽  
S.G. Singh

This paper presents the design & modeling of distributed MEMS phase shifter for Ka band RF systems. The phase shift can be achieved by periodically placing the MEMS bridge variable capacitors as per Bragg frequency criteria on coplanar waveguide (CPW) using GaAs substrate. The EM & electromechanical simulation are carried out with various structural parameters to optimize the designs. The novelties like low insertion loss, low actuation voltage with distributed actuation pads & separate DC and RF are used to make the design unique. The EM simulations are carried out with HFSS and an insertion loss of -3.49 dB at 36GHz for a total Phase shift of 360 deg. was achieved with return loss of - 20.6 dB over a frequency band 34-38 GHz. The electromechanical simulations are carried to achieve the low actuation voltage of 10.3V. The significance of this study is the realization of the digital phase shifter through DMTL approach.


2011 ◽  
Vol 403-408 ◽  
pp. 5330-5334
Author(s):  
Anesh K. Sharma ◽  
Ashu K. Gautam ◽  
D.V.K. Sastry ◽  
S.G. Singh

As the requirement for the low loss phase shifter increases, so does the development of RF MEMS as a solution. This paper presents the design & simulation of Switched line MEMS phase shifter for Ku band using GaAs substrate. The phase shift can be achieved by varying the lengths in delay path to the reference path for the same phase velocity. The electromagnetic & electromechanical simulations were carried out with various structural parameters to optimize the design. The novelties like low insertion loss, low actuation voltage with distributed actuation pads for DC and RF are used to make the design unique. The EM simulations are carried out using 3D simulator HFSS and a phase shift of 172.6 deg./dB for a total Phase shift of 348.75deg was achieved with return loss of 15.5dB over a frequency band from 16-18 GHz and a phase shift error less than ±2 degree in the 32 states. The electromechanical simulations are carried to achieve the low actuation voltage of 15.3V. These parameters make these suitable for the Phased array applications [1, 2].


1993 ◽  
Vol 48 (5) ◽  
pp. 3980-3987 ◽  
Author(s):  
Wiesław Królikowski ◽  
Nail Akhmediev ◽  
Barry Luther-Davies

1994 ◽  
Vol 06 (05) ◽  
pp. 833-853 ◽  
Author(s):  
V. KOSTRYKIN ◽  
R. SCHRADER

Cluster properties of one particle Schrödinger operators are proved, where the potential is the sum of two terms and the center of one is moved to infinity. These cluster properties hold for the on-shell S-matrix elements, the spectral shift functions (and thus the total phase shift) as well as their Laplace transforms, i.e. the traces of the differences of appropriate heat kernels.


2004 ◽  
Author(s):  
Marta Cyganek ◽  
Maciej Wojtkowski ◽  
Piotr Targowski ◽  
Andrzej Kowalczyk

Author(s):  
Kenneth H. Downing ◽  
Benjamin M. Siegel

Under the “weak phase object” approximation, the component of the electron wave scattered by an object is phase shifted by π/2 with respect to the unscattered component. This phase shift has been confirmed for thin carbon films by many experiments dealing with image contrast and the contrast transfer theory. There is also an additional phase shift which is a function of the atomic number of the scattering atom. This shift is negligible for light atoms such as carbon, but becomes significant for heavy atoms as used for stains for biological specimens. The light elements are imaged as phase objects, while those atoms scattering with a larger phase shift may be imaged as amplitude objects. There is a great deal of interest in determining the complete object wave, i.e., both the phase and amplitude components of the electron wave leaving the object.


Author(s):  
J. M. Oblak ◽  
B. H. Kear

The “weak-beam” and systematic many-beam techniques are the currently available methods for resolution of closely spaced dislocations or other inhomogeneities imaged through strain contrast. The former is a dark field technique and image intensities are usually very weak. The latter is a bright field technique, but generally use of a high voltage instrument is required. In what follows a bright field method for obtaining enhanced resolution of partial dislocations at 100 KV accelerating potential will be described.A brief discussion of an application will first be given. A study of intermediate temperature creep processes in commercial nickel-base alloys strengthened by the Ll2 Ni3 Al γ precipitate has suggested that partial dislocations such as those labelled 1 and 2 in Fig. 1(a) are in reality composed of two closely spaced a/6 <112> Shockley partials. Stacking fault contrast, when present, tends to obscure resolution of the partials; thus, conditions for resolution must be chosen such that the phase shift at the fault is 0 or a multiple of 2π.


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