Microwave breakdown of the TE₁₁mode in a circular waveguide

Abstract

This paper investigates the microwave breakdown threshold in a circular waveguide excited in the lowest order (TE11) mode, where the electric field strength depends on both the radius and the azimuthal angle. This analysis complements and extends previous investigations of breakdown in cylindrical waveguides and resonators that have been restricted to circularly symmetric waveguide modes so far. A simple analytical approximation of the breakdown threshold of the TE11 mode is found, using a direct variational approach. The predictions are compared with the results of numerical calculations and the agreement is found to be very good.

Microwave Corona Breakdown Prediction in Arbitrarily-Shaped Waveguide Based Filters

“…As a first validation example, we have compared our algorithm to the theoretical results presented in [7] for an infinite circular waveguide. As shown in Fig.…”

Microwave Breakdown Field in a Resonant Spherical Cavity

“…Since the ionization frequency depends on the electric field strength, the mode structure of the field plays an important role in equation (2). The lowest order mode in a spherical resonator has the components, [4] (correcting for a mistake in the radial field component given in [1])…”

“…In the present analysis we reinvestigate, correct, and generalize (by including attachment losses) this problem. The analysis is analogous to the one used in [2] for investigating breakdown in the lowest order (TE11) mode in a circular waveguide, and is based on a direct variational approach using trial functions for the electron density variation in the resonator and subsequent Rayleigh-Ritz optimization. The results are bench marked against full numerical solutions of the concomitant eigenvalue problem, which validate the good predictive capability of the semi-analytical approximations.…”

Microwave gas breakdown in elliptical waveguides

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Spaceships are subject to the risk of microwave breakdown occurring on the aperture of slot antennas 3,6,7 and/or inside microwave satellite payloads. [9][10][11][12][13] The risk of breakdown appears during the atmospheric entry of space vehicles in planet exploratory missions or during Earth's atmospheric re-entry, as well as in the Telemetry Tracking and Control (TTC) launching phase. The resulting partially ionized gas leads to strong absorption and/or reflection of the incident microwave signal, what can lead to a dramatic increase of the ohmic losses and to a noticeable temperature rise, with the subsequent permanent damage of the instruments.…”

“…In this paper, we apply the Rayleigh-Ritz method to solve the eigenvalue problem of the corona equation. 10,12,28 The results obtained are compared with the circular waveguide, which serves as a reference when the eccentricity of the ellipse tends to zero.…”