Microwave Corona Breakdown Prediction in Arbitrarily-Shaped Waveguide Based Filters

Abstract

Abstract-This letter describes an efficient algorithm to predict the RF gas breakdown power threshold in microwave devices with complex geometries. The two necessary calculations when investigating such a phenomenon have been performed: on the one hand, the computation of the electromagnetic fields inside the structure and, on the other hand, the determination of the breakdown onset itself. The electromagnetic fields are solved by means of modal techniques and coupled to the free electron continuity equation, which is solved by the Finite Element Method. Proceeding in this way, a very simple criterion to find out whether microwave corona breakdown will take place is derived. This numerical implementation of the developed algorithms has been tested with other theoretical approaches and with experimental measurements, showing very good agreement.Index Terms-Electromagnetic simulation, gas discharge, high power, microwave breakdown threshold, microwave filters.

Frequency response of atmospheric pressure gas breakdown in micro/nanogaps

“…These breakdown relationships, however, do not apply when the same p  d values are obtained in GHz to THz gaps at atmospheric pressures when the excitation frequency becomes comparable with the particle collision frequency. While a few theories to calculate breakdown field in high frequencies exist in literature, [21][22][23] these are highly restrictive when applied to micro/nanogaps. For example, AC air breakdown model introduced in Ref.…”

Modeling and characterization of microwave breakdown at atmospheric pressure in OMUX filters

“…Power handling is a severe problem in many different applications, particularly in modern microwave circuits subject to strong microwave signals. Because of strong electromagnetic fields existing within the device, an irreversible failure may occur, due to corona or multipaction in vacuum or at low pressure, or due to microwave breakdown at atmospheric pressure.…”

Full-wave characterization of bi-dimensional cavities and its application to the design of waveguide filters and multiplexers

“…From this solution, the breakdown power level for different pressure conditions is predicted. Figure 3.14 depicts the predicted breakdown levels compared with the measured breakdown level (known as Paschen curve) for the manufactured prototype reported in [144]. As can be seen, the simulation agrees perfectly with measurements.…”

“…Consequently, the study of these types of filters is a logical first step in the prediction of high-power breakdown phenomena. Measured data from a manufactured prototype [143,144], albeit not including rounded corners, will be used to validate the results. In order to perform an adequate comparison, the corners of the critical parts (i.e., the low impedance sections) are not rounded, as shown in Fig.…”

“…As previously mentioned, the low-impedance sections of the filter are prime candidates to experience corona discharge. Once the EM fields are computed in these sections, the continuity equation that governs the evolution of the electron density is solved, using the Finite Element Method (nitrogen has been considered as the filling gas) [144]. From this solution, the breakdown power level for different pressure conditions is predicted.…”