**4.5 Radiation pattern**

*Advances in Array Optimization*

**Figure 12.** *Anechoic chamber.*

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**Figure 13.**

*cavity Vivaldi antenna at 14 GHz.*

*(a) 3-D radiation pattern of single cavity Vivaldi antenna at 14 GHz and (b) 3-D radiation pattern of double* 

The simulated 3D radiation patterns of printed Vivaldi antenna for single cavity and double cavity at frequency of 14 GHz is shown in **Figure 13(a)** and **(b)** respectively.

### **4.6 Plane patterns**

The E-plane and H-plane are the reference planes for linearly polarized waveguides, antennas and other microwave devices. The E-plane and H-plane patterns are also called as the polar plots or gain plots.

## *4.6.1 E-plane*

The plane containing the E aperture and the direction of maximum radiation results in a linearly polarized antenna and it determines the orientation of the radio

*(a) E plane patterns for single cavity Vivaldi antenna and (b) E plane patterns for double cavity Vivaldi antenna.*

wave. The E-plane (XY-plane at θ = 90°) radiation patterns at different frequencies from 8 to 18 GHz for single cavity and double cavity are as shown in **Figure 14(a)** and **(b)**, respectively.
