*2.3.3 Fabrication*

Bi-Ellipse microstripline array varians antenna prototype was fabricated by UV photoresist laminate. In our work, the antenna prototypes are fabricated on Flame Retardant 4 (FR4) material with 4.3 dielectric constant. The first step in the fabrication process is to generate the photo mask artwork by printing on stabline or rubylith negative film of the desired geometry on butter sheet. Using the precision cutting blade of a manually operated co-ordino graph the opaque layer of the stabiline or rubylith film is cut to the proper geometry and can be removed to produce either a positive or negative film representation of the antenna sketches. The design dimensions and tolerances are verified on a cordax measuring instrument using optical scanning. Enlarged artwork should be photo reduced using a high precession camera to produce high resolution negative, which is later used for exposing the photo resist. The photographic negative must be now held in very close contact with the polyethylene cover sheet of the applied photo resist using a vacuum frame copy board or other technique, to assure the fine line resolution required. With exposure to proper wavelength of light, polymerization of the

**Figure 4.** *Fabrication process.*

*Bi-Ellipse Microstripline Antenna Array Varians DOI: http://dx.doi.org/10.5772/intechopen.98834*

**Figure 5.**

*Measuring process in the laboratory using (a) network analyzer and (b) in the chamber.*


#### **Figure 6.**

*(a) S11 parameter graph of the simulation and measurement results in the 8x2 array variant of* bi-ellipse *microstrip antenna, (b) S11 parameter graph of the simulation and measurement result in the 8x4 array variant of* bi-ellipse *microstrip antenna.*

exposed photo resist occurs making it insoluble in the developer solution. Now, it is then coated with a negative photo resist and exposed to UV-radiation and it is immersed in developer solution up to two minutes through the mask. The exposed photo resist hardens and those in the unexposed areas are washed off using a developer. The unwanted copper portions are now removed using Ferric Chloride (FeCl3) solution. FeCl3 dissolves the copper coating on the laminate except which is underneath the hardened photo resist layer after few minutes. Finally, the laminate is then washed with water and cleaned in acetone solution to remove the hardened negative photo resist. The fabrication process has shown in the following **Figure 4**.


#### **Figure 7.**

*(a) Gain graph of the simulation and measurement results in the 8x2 array variant of* bi-ellipse *microstrip antenna. (b) Gain graph of the simulation and measurement results in the 8x4 array variant of* bi-ellipse *microstrip antenna.*
