Table 5 S21 comparison between array and unit cell.

From: Inductively tuned modified split ring resonator based quad band epsilon negative (ENG) with near zero index (NZI) metamaterial for multiband antenna performance enhancement

Band

Resonance Frequency (GHz)

% deviation of the frequency

Unit cell

2 × 2 array

4 × 4 array

8 × 8 array

2 × 2 array

4 × 4 array

8 × 8 array

S

2.38

2.16, 2.56

2.6, 3.44

2.6, 3.1

 − 10, 6.7

8.3,

8.3

C

4.24, 6

4.24, 5.98

4.24, 5.95

4.24, 5.97

0, − 0.4

0, − 0.8

0, − 0.5

X

9.6

9.03

8.8

8.64

 − 5.9

 − 8.3

 − 10

Ku

12.1, 14.4

12.29, 14.16

12.24, 14.06

12.2, 14

1.6, − 1.7

1.2, − 2.38

0.8, 2.8

  1. A minus sign in % deviation indicates shifts of resonance towards lower frequency, whereas positive deviation indicates a shift towards higher.