**4.3 Dual polarized antenna**

Finally, a dual polarized antenna is presented in **Figure 15**, where horizontal and vertical polarizations can be excited from two different isolated ports [70]. The two isolated ports are in different layers as shown in **Figure 15**. The antenna structure is implemented on the top layer and consists of two orthogonal magneto electric (ME) dipoles in the vertical and in the horizontal directions. Therefore, vertical and horizontal linear polarizations are obtained upon exciting the antenna. Each ME dipole is formed by means of two square patches, connected to the ground by five conducting plates at the patch corner [70]. This configuration, when excited properly, formulates an electric dipole from the plates, and a dual magnetic dipole from the vias. The structure in **Figure 15** has then two vertical and horizontal dipoles of each type [70].

**Figure 15.** *ME dipole antenna design and detailed dimensions of each layer.*

*Ridge Gap Waveguide Beamforming Components and Antennas for Millimeter-Wave Applications DOI: http://dx.doi.org/10.5772/intechopen.105653*


#### **Table 16.**

*Dimensions of the magneto-electric dipole antenna and its feeding structure illustrated in Figure 15.*

Among the benefits of using ME dipole antennas are the directive pattern obtained identically in the E- and H-planes, and the stable beam of the antenna as to be illustrated in the subsequent results. **Table 16** summarizes the design dimensions of the ME dipole antenna and its feeding structure.

**Figure 16a** illustrates the simulated and measured S-parameters of this dual polarization ME dipole antenna. With respect to the self-matching of each port, the antenna achieves more than 10 dB return loss over 26.5–33.5 frequency range, which is approximately equivalent to 23% relative bandwidth at 30 GHz [70]. The isolation between the two ports exceeds 20 dB over the band. The simulated and measured gain values for each port are given in **Figure 16b**, indicating around 10 dBi gain for each polarization [70]. The stability of the antenna beam is tested by measuring and simulating the radiation pattern at different frequency values, of which the results at 30 GHz are shown in **Figure 16c** and **d**. These drawn patterns are in E- and H- planes for the two co-polarizations along with their corresponding x-polarization level. The antenna achieves less than �20 dB x-polarization in each case, proving a great performance for polarization diversity applications [70].
