Measurement Technique for Microwave Surface Resistance of Additive Manufactured Metals
- 1 January 2021
- journal article
- research article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Microwave Theory and Techniques
- Vol. 69 (1), 189-197
- https://doi.org/10.1109/tmtt.2020.3035082
Abstract
Additive manufactured (AM) metals are a subject of much interest for their performance in passive microwave applications. However, limitations could arise due to artifacts, such as surface texture and/or roughness resulting from the manufacturing process. We have, therefore, adopted a parallel plate microwave resonator for the accurate measurement of the surface resistance of flat metal plates, allowing for microwave current flow in two orthogonal directions by simply exciting a different resonant mode (at 5.3 and 6.4 GHz), without the need to remove and refix the sample. The systematic and random errors associated with the measurement of surface resistance are very small, less than 1% and 0.1%, respectively. The technique is demonstrated with measurements on a range of samples of the alloys, AlSi10Mg and Ti6Al4V, manufactured by laser powder bed fusion, in addition to traditionally machined samples of bulk metal alloys of aluminum and brass. For AM samples of AlSi10Mg, we have studied the effect on the surface resistance of directional roughness features, generated by the laser raster paths, in directions transverse or parallel to microwave current flow. Importantly for passive microwave device applications, we demonstrate that these samples exhibit no systematic anisotropy of surface resistance associated with such surface features.Keywords
Funding Information
- Engineering and Physical Sciences Research Council (EPSRC) and by Renishaw PLC through the ICASE Studentship Programme (EP/R511882/1)
This publication has 22 references indexed in Scilit:
- Rigorous Computation of Green's Function of a Parallel-Plate Waveguide with a Tapered WallElectromagnetics, 2009
- Numerical method for calculating the apparent eddy current conductivity loss on randomly rough surfacesJournal of Applied Physics, 2004
- Accuracy issues in surface resistance measurements of high temperature superconductors using dielectric resonators (corrected)IEEE Transactions on Applied Superconductivity, 2001
- Improvement of accuracy in measurements of the surface resistance of superconductors using dielectric resonatorsIEEE Transactions on Applied Superconductivity, 1998
- Microwave surface resistance of cuprate superconductorsIEEE Transactions on Applied Superconductivity, 1997
- Measurement of surface impedance versus temperature using a generalized sapphire resonator techniqueReview of Scientific Instruments, 1994
- Parallel plate resonator for accurate RF surface loss measurementsIEEE Transactions on Magnetics, 1991
- A parallel plate resonator technique for microwave loss measurements on superconductorsReview of Scientific Instruments, 1990
- A Dielectric Resonator Method of Measuring Inductive Capacities in the Millimeter RangeIEEE Transactions on Microwave Theory and Techniques, 1960
- Effect of Surface Roughness on Eddy Current Losses at Microwave FrequenciesJournal of Applied Physics, 1949