Compact quasi-periodic and aperiodic TE/sub 0n/ mode converters in overmoded circular waveguides for use with gyrotrons

1990 ◽  
Vol 38 (6) ◽  
pp. 712-721 ◽  
Author(s):  
M.J. Buckley ◽  
R.J. Vernon
Keyword(s):  
Mode Converters ◽  
Circular Waveguides

scholarly journals Calculations on Mode Eigenvalues in a Corrugated Waveguide with Varying Diameter and Corrugation Depth

2021 ◽  
Author(s):  
Daniel Haas ◽  
Manfred Thumm ◽  
John Jelonnek
Keyword(s):  
High Power ◽  
Computational Effort ◽  
Low Earth Orbit ◽  
Low Loss ◽  
High Power Microwave ◽  
Radar Sensors ◽  
Coupled Mode ◽  
Mode Converters ◽  
Circular Waveguides ◽  
Power Microwave

AbstractThe present paper addresses numerical calculations on the eigenvalues of hybrid modes in corrugated circular waveguides with varying diameter and corrugation depth. Such calculations are essential for the numerical optimization of advanced mode converters and diameter tapers for future low-loss high-power microwave applications, like broadband high-power radar sensors for space debris observation in low earth orbit (LEO). Corresponding mode converters and diameter tapers may be synthesized based on coupled mode theory. Of particular importance here is the ability to consider varying mode eigenvalues along the perturbed waveguide. The procedure presented here is able to consider arbitrary variations of the corrugation depth as well as the waveguide diameter and therefore is highly flexible. The required computational effort is low. Limitations of the method are discussed.

scholarly journals A mode generator and multiplexer at visible wavelength based on all-fiber mode selective coupler

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 973-981 ◽  
Author(s):  
Han Yao ◽  
Fan Shi ◽  
Zhaoyang Wu ◽  
Xinzhu Xu ◽  
Teng Wang ◽  
...  
Keyword(s):  
Phase Shift ◽  
Intensity Distribution ◽  
Linear Polarization ◽  
Mode Conversion ◽  
Polarization State ◽  
Stimulated Emission ◽  
Wavelength Multiplexing ◽  
Mode Converters ◽  
Fiber Mode ◽  
Vortex Beams

AbstractUsing an all-fiber mode selective coupler (MSC) at the visible band, here we experimentally demonstrate a generating and wavelength multiplexing scheme for the cylindrical vector (CV) and vortex beams (VBs). The proposed MSCs act as efficient mode converters to produce spectrally insensitive high-order modes (HOMs) at the wavelength ranging from 450 to 980 nm, which have broad operation bandwidth (more than 7 nm), high mode conversion efficiency (94%), and purity (98%), and low insert loss (below 0.5 dB). By adjusting the polarization state and the phase shift of linear polarization (LP)11 mode respectively, the donut-shaped CVs and circular-polarization VBs are achieved. The focused intensity distribution of the donut beam on the cross- and axial-sections is monitored by using a confocal system. The all-fiber solution of producing and multiplexing HOMs opens a new route for stimulated emission depletion microscopy applications.

Rigorous study of propagation in metallic circular waveguide filled with anisotropic metamaterial

2017 ◽  
Vol 9 (4) ◽  
pp. 805-813 ◽  
Author(s):  
Hedi Sakli ◽  
Mohamed Yahia ◽  
Wyssem Fathallah ◽  
Jun Wu Tao ◽  
Taoufik Aguili
Keyword(s):  
Computation Time ◽  
Circular Waveguide ◽  
Transverse Magnetic ◽  
Higher Order Modes ◽  
Anisotropic Metamaterials ◽  
Matching Technique ◽  
Theoretical Predictions ◽  
Rigorous Study ◽  
Circular Waveguides ◽  
Anisotropic Metamaterial

This paper presents an extension of the formulation of wave propagation in transverse electric (TE) and transverse magnetic (TM) modes in the case of metallic circular waveguides filled with anisotropic metamaterials. The determined higher-order modes have been analyzed and exploited to the design of filters. Among the particularities of anisotropic material, the backward waves can propagate below the cut-off frequency. The numerical results for TE and TM modes have been compared with theoretical predictions. Good agreements were obtained. We analyzed a periodic structure containing waveguides filled with anisotropic metamaterial using the mode-matching technique. By using modal analysis, our approach reduced considerably the computation time compared to HFSS.

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