**3. Conclusions**

Here in this chapter, different DGS structures and their characteristics are studied. The hexagonal head dumbbell DGS provides stopband performance with a 4.3% reduced size than the conventional square head dumbbell DGS. The circular split ring DGS is very compact and provides a bandstop response. This type of structure has a very narrow slot gap and a very small cross-sectional area of 0.07 λ<sup>0</sup> 0.07 λ0. This


#### **Table 9.**

*Some advantages of the proposed DGS structures as compared to state of the art.*

DGS structure also provides a very sharp roll-off factor of 79.2 dB/GHz. The above table (**Table 9**) provides some advantages of the proposed DGS structures compared to some unit structures available in the literature. Since here, the main intention is to compare the qualitative analysis of the proposed DGS units to that of the DGS units available in the literature. Due to the non-availability of data, some insertion loss boxes in the above table are kept blank.
