**6. Conclusion**

**Substrate Dimensions Impedance**

Patch <sup>ε</sup>r=9

16 Progress in Compact Antennas

Patch

Patch

Patch with notches

Wirepatch antenna

(tanδ=5.10-4)

εr=2.25 - μr=4 (tanδε=5.10-4 tanδμ=5.10-4)

εr=1 μr=9 (tanδε=5.10-4 tanδμ=5.10-4) **bandwidth**

Patch Air λ0/2 x λ0/2 x λ0/27 4.1% 8.8 98%

λ0/6 x λ0/6 x λ0/76 0.98% 7 89%

λ0/6 x λ0/6 x λ0/76 3.29% 7.2 92%

λ0/6 x λ0/6 x λ0/76 4.66% 7.5 95%

Air λ0/4 x λ0/5 x λ0/68 1.2% 6.4 95%

Air λ0/8 x λ0/8 x λ0/17 3% 4 97%

PIFA Air λ0/6 x λ0/8 x λ0/35 6.5% 6.9 97%

**Radiation Directivity**

**(dBi)**

**Total efficiency**

> To conclude, an overview of classical antennas with their miniaturization techniques has been presented and detailed in this chapter while mentioning a lot of literature references. Classical wire antennas as monopoles present good impedance bandwidth, but they remain too large to be integrated inside last generations of mobile devices. Planar antennas have the advantage to be generally low profiles and thus easier to be integrate. However, patch antennas or planar inverted F antennas have maximum gains relative to the vertical axis. Thus, wire patch antenna presents a good alternative since it radiates as a dipole antenna and is significantly smaller. Concerning the dielectric resonator antennas, they can be miniature and can resonate and be matched on different frequency by creating some partial boundary condition [50].
