*3.1.2.1 S11 parameter*

The parameter S11 is the coefficient that most concerns designers of printed antennas because it represents the reflection coefficient which plays the role of disturbance on data transmission [14]:

We see that the coefficient S is around −22.35 dB for a resonant frequency of 3.8 GHz, the bandwidth is 3.17–15 GHz, as shown in **Figure 8** [15].


#### **Table 3.**

*The dimensions of the circular miniature printed antenna.*

**Figure 8.** *Return loss of circular miniature printed antenna.*
