Characteristics Of Higher-order Modes Research Articles

Theoretical Analysis of Terahertz Dielectric-Loaded Graphene Waveguide.

The waveguiding of terahertz surface plasmons by a GaAs strip-loaded graphene waveguide is investigated based on the effective-index method and the finite element method. Modal properties of the effective mode index, modal loss, and cut-off characteristics of higher order modes are investigated. By modulating the Fermi level, the modal properties of the fundamental mode could be adjusted. The accuracy of the effective-index method is verified by a comparison between the analytical results and numerical simulations. Besides the modal properties, the crosstalk between the adjacent waveguides, which determines the device integration density, is studied. The findings show that the effective-index method is highly valid for analyzing dielectric-loaded graphene plasmon waveguides in the terahertz region and may have potential applications in subwavelength tunable integrated photonic devices.

Measurement of electrodynamics characteristics of higher order modes for harmonic cavity at 2400 MHz

In the frameworks of the High Luminosity Large Hadron Collider (HL-LHC) upgrade program an application of additional superconducting harmonic cavities operating at 800 MHz is currently under discussion. As a possible candidate, an assembly of two cavities with grooved beam pipes connected by a drift tube and housed in a common cryomodule, was proposed. In this article we discuss measurements of loaded Q-factors of higher order modes (HOM) performed on a scaled aluminium single cell cavity prototype with the fundamental frequency of 2400 MHz and on an array of two such cavities connected by a narrow beam pipe. The measurements were performed for the system with and without the matching load in the drift tube..

Higher order modes in an RF deflecting structure

RF deflectors on the basis of a disk-loaded waveguide with different methods for stabilizing the polarization plane of an EH 11 hybrid wave (with two holes in the diaphragm, with an oval-shaped coupling aperture, and with two grooves in a shell) were developed for the system of measuring the length and emittance of an electron bunch in a free electron laser. The electrodynamic characteristics of higher order modes were calculated and measured for the mentioned methods for specifying the wave polarization plane.

Full-wave analysis for propagation characteristics of cylindrical coplanar waveguides with finite thickness of conductor

A full-wave analysis by the extended spectral-domain approach is successfully applied to solve the cylindrical coplanar-waveguide problem. The analysis incorporates the effects of the edge singularities properly and can afford the efficient and accurate calculation method for the characteristic impedances in addition to the phase constants of cylindrical coplanar waveguides (CCPWs) with zero- and finite-thickness conductor. The numerical results obtained by this method have revealed the effect of conductor thickness on the characteristics of higher order modes, as well as the odd and even dominant modes of CCPWs for the first time.

Radiation characteristics and generation of higher-order modes of circular microstrip antennas

The characteristics of higher-order modes of circular micro-strip antennas, such as radiation pattern, directivity, bandwidth, efficiency, and location of the feedpoint to match a 50Ωline, are studied, and the effects of varying the substrate parameters are investigated. A multifeed technique to generate any particular mode is also presented.