3D Printed Porous Dielectric Substrates for RF Applications

In this study, dielectric properties of Acrylonitrile butadiene styrene (ABS) thermoplastic material with different fill-densities are investigated. Three separate sets of samples with dimensions of 25 mm × 25 mm × 5 mm were created at three different machine preset porosities using a LulzBot 3D printer. To understand the actual porosities of the samples, a 3D X-ray computed tomography microscope was used. The great advantage of this 3D microscopy is that it is fully non-destructive and requires no specimen preparation. Hence, the manufacturing defects and lattice variations can be quantified from image data. It is observed that the experimental pore densities are different from the factory preset values. This provides insight to further understand pore distribution-property relationships in these dielectric materials. Micro-strip patch antennas were then created on the 3D printed ABS substrates. The samples were then tested using a vector network analyzer (VNA) and resonant frequencies were measured. It is observed that the resonant frequency increases with an increase in porosity. These results clearly demonstrate the ability to control the dielectric constant of the 3D printed material based on prescribed fill density. Copyright © 2016 by ASM

3D Printed Porous Dielectric Substrates for RF Applications

In this study, dielectric properties of Acrylonitrile butadiene styrene (ABS) thermoplastic material with different fill-densities are investigated. Three separate sets of samples with dimensions of 25 mm × 25 mm × 5 mm were created at three different machine preset porosities using a LulzBot 3D printer. To understand the actual porosities of the samples, a 3D X-ray computed tomography microscope was used. The great advantage of this 3D microscopy is that it is fully non-destructive and requires no specimen preparation. Hence, the manufacturing defects and lattice variations can be quantified from image data. It is observed that the experimental pore densities are different from the factory preset values. This provides insight to further understand pore distribution-property relationships in these dielectric materials. Micro-strip patch antennas were then created on the 3D printed ABS substrates. The samples were then tested using a vector network analyzer (VNA) and resonant frequencies were measured. It is observed that the resonant frequency increases with an increase in porosity. These results clearly demonstrate the ability to control the dielectric constant of the 3D printed material based on prescribed fill density. Copyright © 2016 by ASM

Three-Dimensional Printed Dielectric Substrates for Radio Frequency Applications

Engineered porous structures are being used in many applications including aerospace, electronics, biomedical, and others. The objective of this paper is to study the effect of three-dimensional (3D)-printed porous microstructure on the dielectric characteristics for radio frequency (RF) antenna applications. In this study, a sandwich construction made of a porous acrylonitrile butadiene styrene (ABS) thermoplastic core between two solid face sheets has been investigated. The porosity of the core structure has been varied by changing the fill densities or percent solid volume fractions in the 3D printer. Three separate sets of samples with dimensions of 50 mm × 50 mm × 5 mm are created at three different machine preset fill densities each using LulzBot and Stratasys dimension 3D printers. The printed samples are examined using a 3D X-ray microscope to understand pore distribution within the core region and uniformity of solid volumes. The nondestructively acquired 3D microscopy images are then postprocessed to measure actual solid volume fractions within the samples. This measurement is important specifically for dimension-printed samples as the printer cannot be set for any specific fill density. The experimentally measured solid volume fractions are found to be different from the factory preset values for samples prepared using LulzBot printer. It is also observed that the resonant frequency for samples created using both the printers decreases with an increase in solid volume fraction, which is intuitively correct. The results clearly demonstrate the ability to control the dielectric properties of 3D-printed structures based on prescribed fill density

Three-Dimensional Printed Dielectric Substrates for Radio Frequency Applications

Engineered porous structures are being used in many applications including aerospace, electronics, biomedical, and others. The objective of this paper is to study the effect of three-dimensional (3D)-printed porous microstructure on the dielectric characteristics for radio frequency (RF) antenna applications. In this study, a sandwich construction made of a porous acrylonitrile butadiene styrene (ABS) thermoplastic core between two solid face sheets has been investigated. The porosity of the core structure has been varied by changing the fill densities or percent solid volume fractions in the 3D printer. Three separate sets of samples with dimensions of 50 mm × 50 mm × 5 mm are created at three different machine preset fill densities each using LulzBot and Stratasys dimension 3D printers. The printed samples are examined using a 3D X-ray microscope to understand pore distribution within the core region and uniformity of solid volumes. The nondestructively acquired 3D microscopy images are then postprocessed to measure actual solid volume fractions within the samples. This measurement is important specifically for dimension-printed samples as the printer cannot be set for any specific fill density. The experimentally measured solid volume fractions are found to be different from the factory preset values for samples prepared using LulzBot printer. It is also observed that the resonant frequency for samples created using both the printers decreases with an increase in solid volume fraction, which is intuitively correct. The results clearly demonstrate the ability to control the dielectric properties of 3D-printed structures based on prescribed fill density