**5. Conclusions**

In this chapter, we have described some trends for the computer-aided design of microstrip antennas (patches and printed monopoles) for wireless sensors network applications. With the use of such CAD tools, innovative designs of antennas and arrays with pre-fractals and polar motifs were approached and

their properties checked. The methods of analysis, manufacturing, and measurement have been presented considering different dielectric materials (rigid and flexible) for the manufacture of the antennas. The proposed antennas have been fed by microstrip line, and different feeding techniques have been considered for matching impedances and suppression of harmonic frequencies. The unique properties of space-filling and self-similarity naturally result in more compact and multiband behavior antennas. On the other hand, it is verified from the presented results that the polar elements (like a Rosacea of n-petals) also present the property of space-filling, resulting in more compact antennas. On the other hand, pre-fractals and polar patch antennas generally have their gain and/or bandwidth reduced as the number of iterations increases, which in many wireless applications are undesirable characteristics. To overcome these limitations, we proposed the design of fractals and polar arrangements with dissimilar elements, which allows increasing the bandwidth and gain of simple antennas. Further developments included the design of printed monopole antennas for ultra-wideband applications. Flexible substrates (polyamide and denim) were used in the design of wearable antennas with esthetic appeal. The microstrip antennas with prefractals and polar elements have few design variables and smooth responses in the region of interest, which facilitates all steps of the design methodology.
