Table 4.

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


different stub lengths (L6 = 2.2, 3.1, 4.2 and 5.3 mm). The overall dimension of the

4.2 Electronically switchable ultra-wide band/dual-band band-pass filter using

Ref. [50] proposed a suitable UWB to dual-band band-pass filter with defected ground structure DGS. This filter consists of four parts, namely, meandered inter digital coupled line sections, stepped impedance open stubs, coupled lines, and rectangular DGS. The filter is miniaturized and has a total area of 12.5 10 mm, Figure 21. This filter is fabricated on Duroid Teflon substrate with a dielectric constant of 2.2 and a dielectric height of 0.7874 mm. The UWB mode extends from 3.6 up to 10.6 GHz with attenuation greater than 20 dB up to 18 GHz (upper stopband). The dual passbands extended from 3.8 up to 18 GHz (upper stopband). The dual passbands extend from 3.8 up to 5 GHz and from 9.5 up to 10.8 GHz. The proposed filter suppresses WiMAX and X (military) band of satellite that extends from 7 up to 8 GHz. The filter is designed, fabricated, and measured. The mode of

DGS at input and output ports of the proposed filter produces two resonances at 7.5 and 9.6 GHz and improve the performance of proposed filter while an overall size reduction of 20% is obtained. The meander lines and stepped impedance open stub are also used to reduce the overall size. By adjusting the connection between

the filter is changed by using suitable matrix equipment [50].

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

The simulated and measured S11 and S21 for different L6 lengths, (a) L6 = 2.0 mm, (b) L6 = 3.1 mm,

data and simulated results.

Figure 20.

117

defected ground structures

(c) L6 = 4.2 mm, and (d) L6 = 5.3 mm [48].

Passive Components for Ultra-Wide Band (UWB) Applications

DOI: http://dx.doi.org/10.5772/intechopen.88444
