4.3 Further works

To optimize an integrated antenna array in wireless communication area, we study the mathematical optimization of the integrated antenna array. Under assumption of W ¼ I, we can derive an optimization problem given by

Figure 10. Channel capacity of practical 16-port integrated antenna.

f ¼ max Tr <sup>T</sup>† f g<sup>T</sup> <sup>¼</sup>Mt

support multiple users with the integrated antenna array.

integrated antenna which has a specific T.

Array Pattern Based on Integrated Antenna DOI: http://dx.doi.org/10.5772/intechopen.81087

the next wireless communication technology.

5. Conclusion

A. Appendix

media as

81

E log det INr þ

However, the achievable T is related to various physical parameters such as antenna space and Q-factor. Thus, it is necessary to design the structure of the

On the other hand, there are different constraints and objective functions for T and W as we mentioned. It is possible to apply various beamforming and precoding methods appropriately according to the structure of the integrated antenna array, such as hybrid-beamforming and low-complex precoding. It is also required to

We introduced the integrated antenna array for the 5G communication technology and provided the MIMO channel model for the integrated antenna array. We showed that the integrated antenna can be implemented as practical antenna systems for the wireless communication. We also proposed the practical integrated antenna array with the four-port integrated antenna. Based on the MIMO channel model, we explained the optimization problems for the integrated antenna array. The performance of the integrated antenna array was verified compared to dualpolarization antenna array. It has been shown that the integrated antenna array can achieve higher spectral efficiency than the conventional antenna arrays. Therefore, it could be seen that the integrated antenna array would be an attractive solution for

In a source-free region V filled with a homogeneous medium, the electric field and magnetic field, with assumption of time dependence of exp ð Þ �jωt , satisfy

k

where c is a pilot vector. Here, M rð Þ and N rð Þ are divergence-free and orthogonal. L rð Þ is curl-free and orthogonal with M rð Þ and N rð Þ. Then, an arbitrary electro-

In spherical coordinates, we can obtain the solution to (22) for unbounded

A rð Þ¼ 0: (21)

∇ � M rð Þ, L rð Þ¼ Ψð Þr , (23)

<sup>n</sup> ð Þ kr Ynmð Þ θ; ϕ , (24)

<sup>∇</sup><sup>2</sup> <sup>þ</sup> <sup>k</sup><sup>2</sup> Ψð Þ¼ <sup>r</sup> <sup>0</sup>: (22)

<sup>∇</sup> � <sup>∇</sup> � A rð Þ� <sup>k</sup><sup>2</sup>

A rð Þ is derivable from the scalar potential Ψð Þr which satisfies

M rð Þ¼ <sup>∇</sup> � <sup>c</sup>Ψð Þ<sup>r</sup> , N rð Þ¼ <sup>1</sup>

Consider vector wave functions M rð Þ, N rð Þ and L rð Þ given by

magnetic field can be described with M rð Þ and N rð Þ and L rð Þ [21].

<sup>Ψ</sup>ð Þ¼ <sup>k</sup>; <sup>r</sup> <sup>z</sup>ð Þ<sup>c</sup>

SNR Nt

HH† : (20)

Figure 11. Configuration of antenna arrays.

Figure 12. Channel capacities of various antenna arrays.

Array Pattern Based on Integrated Antenna DOI: http://dx.doi.org/10.5772/intechopen.81087

$$f = \max\_{\mathrm{Tr}\left\{\mathbf{T}^\dagger\mathbf{T}\right\} = \mathcal{M}\_t} \mathbb{E}\left\{\log \det\left(\mathbf{I}\_{N\_r} + \frac{\mathrm{SNR}}{N\_t} \mathbf{H} \mathbf{H}^\dagger\right)\right\}. \tag{20}$$

However, the achievable T is related to various physical parameters such as antenna space and Q-factor. Thus, it is necessary to design the structure of the integrated antenna which has a specific T.

On the other hand, there are different constraints and objective functions for T and W as we mentioned. It is possible to apply various beamforming and precoding methods appropriately according to the structure of the integrated antenna array, such as hybrid-beamforming and low-complex precoding. It is also required to support multiple users with the integrated antenna array.
