Table 2.

Comparison of various substrate materials in flexible antenna design.

Substrate	Dielectric Constant $\left({\mathit{\epsilon }}_{\mathit{r}}\right)$	Dielectric Loss (tanδ)	Thickness (mm)	Ref.
(a) Paper
Photo paper	3.2	0.05	0.44	[42]
Kodak photo	2.85	0.05	0.254	[43]
Synthetic paper	2	0.0022	0.26	[44]
(b) Textile
Denim	1.67	0.0035	2	[6]
Plain woven polyester	2.193	0.004	0.5	[28]
Felt	1.22	0.016	2	[29]
Acrylic fabric	-	-	0.5	[31]
Cordura fabric	2.05	0.025	2	[45]
(c) Polymers
Liquid crystal polymers	3	0.002	0.225	[48]
Polydimethylsiloxane (PDMS)	2.7	0.134	1.5	[24]
Polyethylene (PE)	2.82	0.005	0.125	[55]
Polyethylene terephthalate (PET)	3.16	0.0071	0.125	[56]
Polyimide (PI)	2.91	0.005	0.2	[13]
Poly(tetrafluoroethylene) (PTFE)	2.2	0.0009	0.127	[52]
Kapton polyimide (KP)	3.4	0.002	0.0508	[12]
PDMS-Al2O3-G	15.8	0.052	3.57	[50]
PDMS-GM	1.85	0.014	3	[51]
PTFE/E-glass	2.5	0.003	4	[53]
PTFE/CNT	-	-	2	[54]