Direct metal laser sintering process investigation: application to 3D slotted waveguide antennas

Abstract

Increasing demand for the development of multifunction radio‐frequency‐systems requires the fabrication of complex architectures. Three‐dimensional (3D) direct metal printing direct metal laser sintering (DMLS) has the required properties to build complex and robust parts. To determine whether this technology is able to replace traditional machining methods, it needs to be extensively examined. In the present study, several waveguides operating in a wide‐frequency range, and slotted waveguide antennas with relevant details and shape, operating in the Ku‐band, were designed, machined, assessed and measured. Measurements show that the degradation of component performances are related to the fabrication strategy used. Deterministic defects were observed that make it possible to conceive ways of enhancing manufactured parts. Through this analysis, the authors demonstrate the potential of the DMLS process to construct finely detailed complex and conformal structures.

Electromagnetic performance of Ti6Al4V and AlSi7Mg0.6 waveguides with laser beam melting (LBM) produced and abrasive flow machining (AFM) finished internal surfaces

“…Aluminum (AlSi7Mg0.6) and titanium (Ti6Al4V) rectangular waveguides were fabricated with additive manufacturing. Their transmission losses were found to be two times higher than simulated values at X-band (8-12 GHz) and Ka-band (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) [1,2]. For a copper (CuSn15) rectangular waveguide fabricated with AM, its transmission loss at the V-band (40-75 GHz) was four times bigger than that produced by machining [3].…”

“…Braunisch et al [9] calculated an attenuation constant to account for propagation loss due to rough and smooth conductors. Martin-Guennou et al [35] showed that in a very rough as-built additive manufactured surface with quadratic surface mean roughness of RSq = 32 μm, surface roughness significantly contributed to transmission loss in the K and Q bands. In this study, the average surface roughness of as-built LBM surfaces of four waveguides ranges from 7 to 12 μm Ra.…”

“…They also found about 2 dB reduction in transmission loss in the band (26)(27)(28)(29)(30)(31)(32)(33)(34) in the silver-plated titanium (Ti6Al4V) waveguide surface. Martin-Guennou et al [35] observed that transmission loss decreased about 0.2 dB in the K band (12-40 GHz) and Q band (33-50 GHz) in the gold or silver-plated aluminium (AlSi10Mg) waveguide surfaces.…”

Metal 3D-Printing of Waveguide Components and Antennas: Guidelines and New Perspectives

“…An assessment on planar and conformal 1D and 2D resonant SWAs is presented in [47]. Several orientations and machine settings were studied to obtain consistent parts with high detail resolution and quality.…”

Design of a Slotted Waveguide Antenna Based on TE20 Mode in Ku-Band Suitable for Direct Metal Laser Sintering

“…For the case of the SWA array, the RF performances are sensitive to dimensional variations from manufacturing, particularly the size of resonant coupling irises placed between the radiating waveguides and the feeding network [9]. These iris dimensions are difficult to control when using the DMLS manufacturing process [10,11], and no post-process or adjustment is possible inside the structure. The use of the TE20 mode to feed substrate integrated waveguide (SIW) travelling wave antennas or SIW slot arrays has already been described [12][13][14], but SIW SWA arrays suffer from dielectric losses and greater dispersion than air-filled devices [15].…”