The objective of this paper is to use electromagnetic-based computer-aided design (CAD) tools to investigate the maximum tuning range of channel filters, typically used in satellite payloads. Both circular and rectangular waveguide technologies are investigated. The results of the investigation show that single-mode rectangular waveguide implementations offer substantially wider tuning range, as opposed to classical dual-mode circular waveguide implementations. In addition to simulations, measurements are also presented indicating very good agreement with theory, thereby fully validating the CAD procedure.

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Exploring the Tuning Range of Channel Filters for Satellite Applications Using Electromagnetic-Based Computer Aided Design Tools

: This document is intended to serve as a standard and handbook for the prevention of multipactor and ionization breakdown in spacecraft components and systems. The document provides minimum requirements for risk definition, system analysis, and component analysis and test. Supporting documentation describes proper design, analysis, and test guidelines while also providing the requirements for defining the proper system engineering to identify RF breakdown risks within susceptible components. The document framework is based on defining worst-case parameters as general inputs to analysis or test criteria for all components within the RF system. Using hardware-specific values, these worst-case parameters are defined separately from margin requirements. With properly defined worst-case conditions, the document addresses required margins for analysis and test for multiple devices categories. Subsequent sections provide minimum verification requirements to demonstrate the margin recommendations for both analysis and test. Applicability of different analysis and test methods to the device class categories is provided, with special cases and considerations. Multiple appendices based on state-of-the-art industry best practices are also provided as guidelines to aid manufacturers and contractors. Typical approaches including examples for both design and test are provided. A reference geometry is described along with corresponding analysis and test data. This information can be used as a benchmark standard, such that component vendors and manufacturers can have a standard example for RF breakdown.

Standard/Handbook for Multipactor Breakdown Prevention in Spacecraft Components

The increase of RF power on board of telecommunication satellites (in terms of power per carrier and number of carriers) requires power handling improvement on RF equipment, in particular with respect to the multipactor phenomenon. From the design step, it is necessary to accurately predict the power threshold to avoid over-designed components. At validation test step, realistic margins definition is needed to prevent performing tests at too high power levels but without taking any risks. Currently, studies are in progress to provide better understanding of this effect. The EVEREST project, funded by ESA with CNES acting as prime contractor, brings together all the major European players in the field around these issues. The main objective is to collaborate on several topics: prediction software, test procedures, cross-validation between measurement and simulation results, etc ... The ultimate goal is to propose relevant updates of the multipactor ECSS document. Thales Alenia Space France is involved in the EVEREST project and has participated in various stages especially in design, manufacturing and measurement of different multipactor samples. This paper presents the development and the results obtained in the frame of this study, and compares predictions and measurements on some samples.

TAS-F multipactor results in EVEREST project

As part of the EVEREST project of ESA, we implemented in CST Particle Studio™ models of different microwave samples for L- and Ku- bands to investigate the Multipactor effect in the presence of the fringing fields. Using a diversity of Secondary Electron Yield (SEY) data provided from different measurement facilities along with the available ECSS standards, cross validation is examined between the simulation Multipactor results and thresholds achieved by the measurement activity. This study is important in determining the source of inconsistency between both activities. It also provides the possibility to update the existent Multipactor chart for fringing field structures. The convergence studies to acquire accurate numerical results are also presented.

Investigation of multipactor effect in microwave components in the presence of fringing fields

Novel explicit formulas are introduced in this paper for the prediction of peak voltages and amplification factors in stepped-impedance coaxial and waveguide low-pass filters. Based on a coupling-matrix model and a simplified electromagnetic (EM) formulation, voltages in the filter critical areas are calculated analytically, without need of any 3-D EM simulations. Only filter prototype parameters are required in this method, which is therefore fast and considerably simplifies the power-handling analysis of corrugated filtering structures. The accuracy of the formulas is verified via commercial finite-difference time-domain software and multipactor breakdown test.

Simplified Prediction of Peak Power-Handling Capability for Stepped-Impedance Low-Pass Filters

The multipactor effect is a constraining phenomenon in the design of RF components Due to an increasing number of channels and power levels for multicarrier signals, specific requirements of design must be taken into account in order to prevent the multipactor effect The current methods of analysis are based on the Hatch and Williams diagrams, which provide the multipaction threshold voltage for a parallel plate geometry as a function of the frequency gap product However, whereas experimental results have shown good correlation with the theoretical charts for the parallel plate geometry, discrepancies have been found for complex geometries such as irises

J.M.E. Lopez

Papers

Experimental validation of fringing field effects for the multipactor phenomenon

Highlights of the fringing field effects at C-band on waveguide components