Design and miniaturization of volumetric RF components and systems in additive manufacturing with 3D printing

 Thursday, November 28, 2024 at 9 am
 

Defense of doctoral thesis by Bastien PERES, for the  University  Grenoble Alpes, speciality  " OPTIC & RADIO FREQUENCIES  "

Keywords :
RF systems,Design,additive manufacturing

Abstract :
Satellite telecommunications, like terrestrial telecommunications, make it possible to transmit information from one place on Earth to another. Since several transmitters and receivers share a limited frequency band, each one is a source of noise for the other and it is necessary to define communication channels between them, made physically by Radio Frequency (RF) filters, in order to limit noise for each communication. A filter must support high power levels, be very selective depending on its role and as compact as possible. The need for a good power handling capability within satellites requires the use of metallic waveguide filters, despite their mass and large volume. It is therefore essential to make satellite components as compact and light as possible to meet market needs and potentially extend the lifespan of future satellites. The evolution of manufacturing technologies for waveguide components makes it possible to improve the aspects of compactness and lightness and therefore efficiency of a satellite.
Two main families of manufacturing technologies are today available to produce cavity filters: subtractive manufacturing and additive manufacturing. The principle of subtractive manufacturing is to mill the material using a cutting tool to obtain the desired shape, whereas to achieve the same geometry in additive manufacturing, the part is formed by stacking layers. The use of a cutting tool in subtractive manufacturing requires access to the area to be machined, making it impossible to manufacture a filter in a single piece and limits the machinable geometries mainly to rectangles, ellipses and spheres. To make a filter, it would be necessary to machine at least two parts and then assemble them. Within each machined piece, a part has the sole function of aligning two pieces with each other and the addition of flanges may be necessary to screw the parts to each other.
Additive manufacturing offers itself as a solution to these limits with the possibility of manufacturing filters layer by layer in a single piece, thus removing the volume and weight of the elements which only serve to assemble two pieces together. The different additive manufacturing techniques make it possible to manufacture filters with high selectivity and allow greater freedom in the geometry of the filters to be designed compared to subtractive manufacturing, although with technical limits in terms of surface roughness and shapes physically achievable.
The company AML Microtechnique Lorraine has been supplying hollow metal waveguides for several decades for the field of space telecommunications used in the payload of a satellite. The evolution of additive manufacturing technologies led a strong interest in manufacturing hollow metal components with a strong improvement in surface roughness on metal powder-based manufacturing. The research work developed during this thesis is part of the “Innovative Post Process and Microwave Design” (I2PMD) project of the company AML Microtechnique Lorraine in collaboration with the Center for Radiofrequency Optics and Micro-nanoelectronics of the Alps (CROMA). This work has 2 main objectives: