**3. Principle of operation**

The Vivaldi antenna belongs to travelling wave antennas. The principle of operation of the surface wave antennas can be divided into two sections: propagating section and radiating section.

**135**

**Figure 1.** *Vivaldi antenna.*

*Characterization of Printed Podal Vivaldi Antenna (8–18 GHz) on RT Duroid with Single…*

2.the taper factor influences the impedance matching; and

Apart from these, the design parameters are as follows:

The length and width of the antenna are optimized.

1.the flare height and length should be greater or equal to half wavelength at

3.the cavity diameter should be equal to 0.2 λ times the minimum operating

The separation between the conductors is smaller than one-half free space wavelength (λ0/2) [5] and the waves travelling down the curved path along the antenna are tightly bound to the conductors in the propagating section. The energy gets radiated into the air in the radiating section where the slot width is increasing beyond the one-half wavelength. Radiation from high-dielectric substrates is very low and hence for antenna applications significantly low dielectric constant materi-

Depending on the dimensions of the transmission line the characteristic impedance is calculated and the vivaldi antenna is printed on both sides of the substrate with a dielectric constant, εr = 2.2 and thickness of the substrate is h = 0.508 mm.

From **Figure 1**, the parameters of Vivaldi antenna are described as:

*DOI: http://dx.doi.org/10.5772/intechopen.88727*

minimum operating frequency;

frequency.

als are chosen.

1. antenna length;

2. antenna width;

3.mouth opening;

4.throat length;

5. edge offset; and

6.backwall offset.

**3.2 Construction**
