A Study of the Anechoic Performance of Rice Husk-Based, Geometrically Tapered, Hollow Absorbers

Table 1

Measured range of dielectric properties of the two fabricated samples in different frequency bands.

Sample	Properties	C-band; (4–8 GHz)	X-band; (8–12 GHz)	𝐾𝑢-band; (12–18 GHz)
Rice husk	𝜀^′𝑟	2.50–2.80	2.00–2.60	1.75–2.25
	𝜀𝑟^′′	0.45–0.60	0.30–0.48	0.30–0.40
Tire dust	𝜀^′𝑟	3.90–4.50	3.25–3.90	3.06–3.60
	𝜀𝑟^′′	0.25–0.40	0.17–0.25	0.17–0.30