Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A 3D-printed broadband millimeter wave absorber   We present the design, manufacturing technique, and characterization of a
3D-printed broadband graded index millimeter wave absorber. The absorber is
additively manufactured using a fused filament fabrication (FFF) 3D printer out
of a carbon-loaded high impact polystyrene (HIPS) filament and is designed
using a space-filling curve to optimize manufacturability using said process.
The absorber's reflectivity is measured from 63 GHz to 115 GHz and from 140 GHz
to 215 GHz and is compared to electromagnetic simulations. The intended
application is for terminating stray light in Cosmic Microwave Background (CMB)
telescopes, and the absorber has been shown to survive cryogenic thermal
cycling.

1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat