Mode Degeneracy in Circular Cylindrical Ridge Waveguides

Abstract

Abstract-Studies of dual channel, polarisation agile, quad-ridge and octo-ridge feeds suggest that mode degeneracy in multi-ridge structures severely constricts operational bandwidths, for a large range of ridge dimensions. Mode characteristics in dual-ridge, quad-ridge and octoridge waveguide are examined in this paper, with a view to identifying both the nature of the degeneracy, and its implications for bandwidth. The results presented have been generated using a full-wave finite element electromagnetic field simulator.

Dual-mode quadruple ridge waveguide feed for broadband satellite communications

“…The above observation was instrumental in the development of the idea of forming a ridge waveguide structure, which enables the Ku-band to exist on quasi-TE 11 ridge modes (Sangster and Grant 2009), while supporting C-band independently in 'isolated' channel modes. The concept is illustrated in Figure 2, which shows simulated fields for a quadridge structure with hollowed out ridges.…”

“…Again, the fixed horn aperture, as with the corrugated horn, displays a troublesome degree of beam-width sensitivity to changing frequency, for an application which seeks operation over a three octaves bandwidth. While the tapered ridge horn is less sensitive to radiation pattern distortion due to moding than a corrugated horn, the control of higher order modes can still be an issue (Sangster and Grant 2009).…”

“…Quad-ridge waveguide with channelised ridges 2.1. Quad-ridge waveguide Electromagnetic modelling studies, which have been carried out on dual-ridge, quad-ridge and octo-ridge cylindrical waveguides (Sangster and Grant 2009), have exposed serious bandwidth limitations as alluded to above. But, rather interestingly, in addition to demonstrating these bandwidth deficiencies, the simulations have revealed that a range of low order modes can occur on quad-ridge and octo-ridge structures, whose fields exist mainly in the inter-ridge spaces rather than in the ridge gaps.…”

Simulations of multipactor in circular waveguides

“…24 where the multipactor has been simulated numerically, although in very narrow waveguides compared to those used in practical applications. 25,26 Therefore a more detailed and general analysis is motivated for the important problem of multipactor discharges in circular waveguides. One step in this direction is presented in the present work where the multipactor discharge is simulated numerically in a waveguide having larger width than that studied in Ref.…”

A Higher Order Analysis of a Class of Inhomogeneously Filled Conducting Waveguides

“…Conducting waveguides of different cross sections have been used in microwave measurements [1][2][3] and in the design of various microwave components [3][4][5][6][7] specially, in the case of high power transmission of electromagnetic waves [3,7]. A variety of analytical and numerical techniques have been applied to the analysis of uniform hollow conducting waveguides.…”