*Orbital Angular Momentum Wave and Propagation DOI: http://dx.doi.org/10.5772/intechopen.104477*

shows that Gaussian amplitude pattern of PWPA, whereas ring-like amplitude pattern for OWPA. Measured and simulated radiation patterns for E-plane and H-plane are demonstrated in **Figure 17(h)**, intriguingly showing a Gaussian pattern for PWPA, on the other hand, second-order Bessel beam pattern for OWPA. The radiation pattern is measured in our SATIMO starlab setup, as shown in **Figure 22**. It can be seen that merely 2 (lin) difference of the simulated and measured realized gain caused by the surface waves loss, dielectric loss in patch antenna, and 0.5 dB error in measurement in the SATIMO setup. The realized gain of PWPA is twice as much as OWPA, as the beam in OWPA is ring-like, and the gain is divided. Although PWPA has higher gain and power flow, OWPA power flow covered area is larger.

**Figure 17.**

*Simulated PWPA (left) and OWPA (right). (a) E-field, (b) H-field, (c) cylindrical E-near-field scan, (d) E-pattern far-field, (e) phase pattern far-field, (f) power flow far-field, (g) 3D realized gain. Also, the 1D-polar plot of measured and simulated (h) realized gain (Lin) of PWPA and OWPA.*
