Material Selection for Axial Magnetization of a Gyromagnetic NLTL for Space Applications

André F Teixeira,Maria C A Nono,José O Rossi,Ana Flâvia G Greco,Edl Schamiloglu,Daniel A Nono,Fernanda S Yamasaki,Joaquim J Barroso,Elizete G L Rangel

doi:10.1590/2179-10742021v20i3254769

Abstract

Nonlinear Transmission Lines (NLTLs) are a new technique for radio frequency (RF) generation. A loaded ferrite NLTL, known as a gyromagnetic line, uses a solenoid to provide an external magnetic bias. In space applications, specifically in satellites, the replacement of these solenoids by permanent magnets is desirable, eliminating the need for a DC current source, and reducing the weight and the effective cost of the launch. This work investigated and selected permanent magnets for this application, and then computationally modeled the magnet assembly to analyze the resulting magnetic field generated and obtained a uniform field region to meet the NLTL operating specifications. For this, we employed selection charts for the proper choice of material to use in an arrangement of magnets simulated by the electromagnetic software CST Microwave Studio . Magnetic fields with uniformity variations of less than 6% and 23% in regions extended over 18.5 cm and 58.8 cm, corresponding to line lengths of 26.6 cm and 68.0 cm, respectively, were achieved in simulations.

Highlights

Nonlinear Transmission Lines (NLTLs) are devices used to generate radiofrequency (RF) for the replacement of electronic vacuum tubes and their thermionic filaments [1]
Material Selection It is observed in the selection charts that ceramic magnets have lower remanence compared to the others
Despite having some limitations regarding the maximum operating temperature, neodymium magnets perform very well with a smaller volume of material. This allows for a compact NLTL with high demagnetization and mechanical resistance characteristics

Summary

Introduction

Nonlinear Transmission Lines (NLTLs) are devices used to generate radiofrequency (RF) for the replacement of electronic vacuum tubes and their thermionic filaments [1]. This technology represents a new alternative to generate RF without the use of an electron beam or need for a vacuum. MHz) [2], [3] where at least one component must be nonlinear (L or C) and (2) a continuous coaxial line, called a gyromagnetic line, operating in L band (1-2 GHz) [4]. The magnetic propagation medium is formed by magnetic ferrite

Methods

Results

Conclusion