**3.1 Design of circular miniature printed antenna**

## *3.1.1 Antenna geometry*

*Advanced Radio Frequency Antennas for Modern Communication and Medical Systems*

**82**

**Table 2.**

*Performance comparison.*

**Figure 5.**

**Figure 6.**

*Effect of the thickness of the substrate.*

*Effect of the inner radius on the antenna.*

**Antennas Characteristic of the antennas**

Antenna proposed 25 mm × 30 mm 2.7–10.98 GHz 3.5 dBi Antenna [7] 30 mm × 32 mm 3.1–9.9 GHz — Antenna [8] 75 mm × 85 mm 4–9.5 GHz — Antenna [9] 24 mm × 30 mm 4.82–8.87 GHz 3.9 dBi

**Dimension (w × L) Bandwidth Gain**

The patch of radius (r) is produced on a substrate of the FR-4 type (dielectric permittivity εr = 4.3, thickness h = 1.575 mm) and of dimensions ls = 25 mm and ws = 25 mm. A rectangular slot is inserted on the radiating element (u × s) ensuring its miniaturization. The latter is supplied by microstrip line of wm east width in order to adapt it to a 50 Ω supply [11, 12]. **Figure 7** shows the proposed antenna.

From **Table 3** values, we perform a simulation on the CST software [13].
