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

direction of the antenna element can be changed according to θrad, because the antenna element radiates perpendicularly to the antenna structure. The parameters are given by L ¼ 70 mm, W ¼ 66 mm, lc ¼ 22 mm, wc ¼ 1:5 mm, ls ¼ 24:5 mm, ws ¼ 1:5 mm, lf ¼ 6:2 mm, wp ¼ 8 mm and lp ¼ 32 mm. It is possible to control the impedance matching by modifying l<sup>7</sup> and w6. The integrated antenna is produced on a CER-10 substrate with a permittivity of 10 and a thickness of 0.64 mm. The

Figure 4.

transmitting coefficient matrix of the transmit integrated antenna and an N � N identity matrix. The covariance matrix of the MIMO channel H can be described as

Rm� T� <sup>0</sup>

P k^r; k ^t � �

� �

. Here, B k^<sup>r</sup>

is the position of the lth array element and r<sup>o</sup> is the position of the antenna array

We explained the channel models for the MIMO system with the integrated antenna arrays mathematically. In the following section, we will verify the performance of the integrated antenna array based on the channel model we discussed.

There have been many practical antennas which are designed for the integrated antenna. Through some practical antennas, we can see that the integrated antenna may be implemented for the wireless communication. Design of the integrated antenna is dependent on the system requirement such as array structure and channel environment. In this section, we introduce various practical integrated antennas

It is important to integrate multiple antennas with compact size, which have orthogonal radiation patterns of each other. There are practical integrated antennas without considering array structure as shown in Figure 4. It is found that the integrated antenna has two types of antenna elements which have radiation patterns of electric dipole antenna and magnetic loop antenna. Planer inverted-F antennas (PIFA) are used for the electric dipole antenna, and quarter-wavelength slot antennas are used for the magnetic loop antenna [16, 17]. It is also seen that the integrated antennas have three-dimensional structures because the array structure was not considered. Therefore, it is noted that the integrated antenna may consist of

The integrated antenna array may be implemented as shown in Figure 5. It is found that the practical integrated antenna array is composed of Lt array elements. Each array element consists of Bt antenna elements, which are designed by utilizing

To reduce the antenna size, we eliminated a conduct strip in front of the antenna element and designed that l<sup>3</sup> is larger than w<sup>2</sup> as shown in Figure 5a. The radiation

<sup>⊗</sup>R� � �†

m� † n o

B~† k ^r; k ^t � �

<sup>¼</sup> <sup>e</sup><sup>r</sup> ^ kr � �

, (15)

dΩrdΩt, (16)

<sup>¼</sup> ej<sup>β</sup>ð Þ <sup>r</sup>l�r<sup>o</sup> <sup>k</sup>^

, and the E k^

� �

, where r<sup>l</sup>

. Here, the correlation

⊗A k^<sup>r</sup> � �

� �

<sup>⊗</sup>R� � �

<sup>m</sup>� , <sup>m</sup>� <sup>¼</sup> vec <sup>M</sup>� � � and <sup>R</sup>m� <sup>¼</sup> <sup>E</sup> <sup>m</sup>�

<sup>R</sup><sup>h</sup> <sup>¼</sup> <sup>T</sup>� <sup>0</sup>

matrix of the channel of the SVW modes can be given by

⊗B k^<sup>t</sup> � �

is an array element response matrix with the elements of el k^

ðð B~ k ^r; k ^t � �

where <sup>h</sup> <sup>¼</sup> <sup>T</sup>� <sup>0</sup>

where B~ ^

system.

kr; ^ kt � �

3. Practical antenna design

3.1 Practical integrated antenna

more than two antenna elements practically.

3.2 Practical integrated antenna array

a planer Yagi-Uda antenna [18].

74

for several cases.

<sup>⊗</sup>R� � �

Array Pattern Optimization

<sup>R</sup>m� <sup>¼</sup> <sup>4</sup>π<sup>2</sup>

<sup>¼</sup> <sup>B</sup> <sup>k</sup>^<sup>r</sup> � �

Configuration of practical integrated antennas. (a) 6-port integrated antenna and (b) 16-port integrated antenna.

#### Figure 5.

Configuration of practical integrated antenna array. (a) Antenna element for 4-port integrated antenna, (b) 4-port integrated antenna and (c) 4-port integrated antenna based 1 � 4 array.

integrated antenna is expandable to the array structure as shown in Figure 4c, because of the compactness of the integrated antenna.

It is necessary to verify that the integrated antenna has reasonable antenna characteristics such as radiation efficiency, bandwidth and mutual coupling. The proposed four-port integrated antenna was implemented as shown in Figure 6. For the integrated antenna, the antenna elements have the same antenna characteristics of each other because of symmetric configuration. The simulated and the measured S-parameters of the integrated antenna are shown in Figure 7a and b, respectively, where Saa means S1, 1, S2,2, S3, <sup>3</sup> and S4,4; Sab means S1, 2, S1,4, S2, <sup>3</sup> and S3,4; and Sac means S1,<sup>3</sup> and S2,4. The integrated antennas radiate at 5.7 GHz with a bandwidth of about 300 MHz satisfying ∣Saa∣ ¼ �10 dB in the simulation and measurement. It is also found that the antenna elements have less than �12 dB mutual couplings in the simulation and measurement.

The simulated and measured S-parameters of the integrated antenna-based 1 � 4 array system are shown in Figure 8a and b, respectively. Only the Sparameters for Port 5 are illustrated because the integrated antenna-based array has

> a symmetric configuration. It is found that the mutual coupling between antenna elements of different array elements is lower by about 13 dB in simulation and measurement results. Thus, it can be noted that the integrated antenna is scalable in

S-parameters of integrated antenna-based 1 4 array. (a) Simulated results and (b) measured results.

found that the simulated and measured radiation patterns are agreed well. It is shown that the antenna elements radiate to y-axis in order to support the front area of the antenna structure and have different radiation patterns. The radiation patterns generated by using the transmitting coefficient matrix T are similar to the simulated radiation patterns as well. Thus, it can be noted that the radiation patterns of the practical antenna can be described in a mathematical expression.

The radiation patterns of the integrated antenna are illustrated in Figure 9. It is

the array structure.

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

Figure 8.

Figure 9.

77

Radiation patterns of proposed four-port pattern antenna.

Figure 6. Prototype of four-port integrated antenna.

Figure 7. S-parameters of four-port integrated antenna. (a) Simulated results and (b) measured results.

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

integrated antenna is expandable to the array structure as shown in Figure 4c,

It is necessary to verify that the integrated antenna has reasonable antenna characteristics such as radiation efficiency, bandwidth and mutual coupling. The proposed four-port integrated antenna was implemented as shown in Figure 6. For the integrated antenna, the antenna elements have the same antenna characteristics of each other because of symmetric configuration. The simulated and the measured S-parameters of the integrated antenna are shown in Figure 7a and b, respectively, where Saa means S1, 1, S2,2, S3, <sup>3</sup> and S4,4; Sab means S1, 2, S1,4, S2, <sup>3</sup> and S3,4; and Sac means S1,<sup>3</sup> and S2,4. The integrated antennas radiate at 5.7 GHz with a bandwidth of about 300 MHz satisfying ∣Saa∣ ¼ �10 dB in the simulation and measurement. It is also found that the antenna elements have less than �12 dB mutual couplings in the

The simulated and measured S-parameters of the integrated antenna-based

parameters for Port 5 are illustrated because the integrated antenna-based array has

1 � 4 array system are shown in Figure 8a and b, respectively. Only the S-

S-parameters of four-port integrated antenna. (a) Simulated results and (b) measured results.

because of the compactness of the integrated antenna.

simulation and measurement.

Array Pattern Optimization

Figure 6.

Figure 7.

76

Prototype of four-port integrated antenna.

Figure 8. S-parameters of integrated antenna-based 1 4 array. (a) Simulated results and (b) measured results.

a symmetric configuration. It is found that the mutual coupling between antenna elements of different array elements is lower by about 13 dB in simulation and measurement results. Thus, it can be noted that the integrated antenna is scalable in the array structure.

The radiation patterns of the integrated antenna are illustrated in Figure 9. It is found that the simulated and measured radiation patterns are agreed well. It is shown that the antenna elements radiate to y-axis in order to support the front area of the antenna structure and have different radiation patterns. The radiation patterns generated by using the transmitting coefficient matrix T are similar to the simulated radiation patterns as well. Thus, it can be noted that the radiation patterns of the practical antenna can be described in a mathematical expression.

Figure 9. Radiation patterns of proposed four-port pattern antenna.
