4.1.2 Fabrication and measurements

The filter was fabricated using a photolithographic technique on Rogers RT/ Duroid 5880 with ε<sup>r</sup> = 2.2, h = 0.787 mm, and tan δ = 0.0009. The photograph of the fabricated filter is shown in Figure 19. The measured and simulated S11 and S21 for different stub lengths are shown in Figure 20(a)–(d). The UWB bandwidth extends between 3.1 and 10.6 GHz. There are four notched frequencies for the

Figure 19. A photo for the fabricated filter [48].

#### Figure 20.

4.1.2 Fabrication and measurements

(fnotch) against (L6) variation [48].

Table 4.

Figure 18.

The proposed filter [48].

UWB Technology - Circuits and Systems

Table 5.

Figure 19.

116

A photo for the fabricated filter [48].

The filter was fabricated using a photolithographic technique on Rogers RT/ Duroid 5880 with ε<sup>r</sup> = 2.2, h = 0.787 mm, and tan δ = 0.0009. The photograph of the fabricated filter is shown in Figure 19. The measured and simulated S11 and S21 for different stub lengths are shown in Figure 20(a)–(d). The UWB bandwidth extends between 3.1 and 10.6 GHz. There are four notched frequencies for the

L1 L2 L3 L4 L5 L7 L8 w1 w2 9.3 3.4 4 5.2 7.2 5.3 3.3 0.3 0.2 g1 g2 g3 g4 g5 g6 g7 g8 g9 0.3 0.9 0.9 0.2 0.3 0.4 0.2 0.2 0.5

Diode states L6 (mm) fnotch (GHz) D1, D2, D3 (off) 2 6.18 D1(on), D2, D3 (off) 3.1 5.9 D1, D2(on), D3(off) 4.2 5.7 D1, D2, D3 (on) 5.3 5.5

Optimized dimensions of the proposed filter (all dimensions are in mm) [48].

The simulated and measured S11 and S21 for different L6 lengths, (a) L6 = 2.0 mm, (b) L6 = 3.1 mm, (c) L6 = 4.2 mm, and (d) L6 = 5.3 mm [48].

different stub lengths (L6 = 2.2, 3.1, 4.2 and 5.3 mm). The overall dimension of the filter is 16.4 5 mm, which is considered very compact compared to other published designs with the same characteristics. Figure 20(a) shows the measured and simulated S11 and S21 with L6 = 2 mm and fnotch = 6.18 GHz. Figure 20(b) shows the measured and simulated S11 and S21 with L6 = 3.1 mm and fnotch = 5.9 GHz. Figure 20(c) shows the measured and simulated S11 and S21 with L6 = 4.2 mm and fnotch = 5.7 GHz. Figure 20(d) shows the measured and simulated S11 and S21 with L6 = 5.3 mm and fnotch = 5.5 GHz. Good agreement was found between the measured data and simulated results.
