A High-Density L-Shaped Backscattering Chipless Tag for RFID Bistatic Systems

Table 1

Comparison of different chipless RFID tags (bistatic measurements).

Resonators’ type	Frequency range (GHz)	Coding spatial capacity (bits/cm^2)	Coding spectral capacity (bits/GHz)	Coding density (bits/GHzcm^2)	Read range (cm)
C-folded dipoles [21]	2–5	1.25	5	0.416	80
SAW [22]	2.44	1	NA	NA	NA
Delay line [23]	3.1–10.6	0.17	1.06	0.023	80
Slot [24]	3.1–10.6	4.17	3.2	0.556	60
C-shaped [25]	2–4	1.14	10	0.57	50
Stub-loaded [26]	2.5–5.5	1	2.66	0.33	50
Stepped impedance [27]	3.1–10.6	7.9	10.53	1.053	50
Slot-loaded [28]	7–12	1.47	3.2	0.29	5
Split ring resonators [29]	2-3	2.37	16	2.37	NA
U-shaped strip [30]	2–4	1.09	10	0.545	30
U-shaped strip [31]	2–4	0.769	10	0.385	25
Double inverted U [32]	4–14	7.73	2.99	1.546	NA
DP U shape [33]	7–12	16.6	3.2	3.32	20
Nested concentric square loops [34]	8–14	19	3	3.16	20
This work	6.5–10.5	18.8	4.5	4.7	80