Additively-Manufactured Circuit-Analog Absorbers Printed From Two Materials

Open Access
Prince, Theodore Jackson
Area of Honors:
Electrical Engineering
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Erik Henry Lenzing, Thesis Supervisor
  • Dr. Julio V. Urbina, Honors Advisor
  • Prince
  • Electromagnetics
  • Additive Manufacturing
  • 3D Printing
  • Reflection
  • Complex Permittivity
  • X-Band
  • Ku-Band
  • Polylactic Acid
  • PLA
  • Circuit-Analog Absorber
  • Absorber
  • Materials Characterization
  • Transmission Line Model
  • Metal Powder
  • Graphite
This thesis presents four different additively-manufactured (3D printed) circuit-analog (CA) absorbers. The CA absorber designs investigated the use of two substrate materials as well as varying frequency selective surface (FSS) topologies. The complex permittivities of polylactic acid (PLA), bronze, brass, copper, and iron powder infused PLAs, and a graphite PLA composite were measured using a free-space materials measurement system. The graphite PLA was selected for the FSS layer of all absorbers, while iron powder PLA and standalone PLA were selected as substrates. Complex permittivity data from the selected materials were input to CST Microwave Studio. Absorber dimensions were optimized using CST’s genetic algorithm. Reflection measurements of the printed absorbers were made using the free-space measurement system with the FSS and associated substrate vacuum-bagged to an aluminum ground plane. Measured results were compared to those from CST and the other prototype absorbers. The results showed that CA absorber designs fabricated using additive manufacturing are possible.