Array antenna characteristics enhancement for electronic scanning radar application: Parasitic patches and multi layer techniques

This paper presents characteristics improvement of patch array antenna used for electronic scanning radar application. This basic array antenna, designed on low cost substrate FR-4 and fed by microstrip technique, consists of 8 patches and operates at frequency 3GHz. However, this structure has two disadvantages a low gain value by dint of using a lossy material FR4 as a substrate, and a narrow bandwidth which is due to microstrip antenna limitations. Hence, the objective of this work is to increase the gain and the bandwidth of this structure. Therefore two techniques will be proposed separately in this paper: parasitic patches and multi layer substrate. For the first one, it consists of adding a defined number of parasitic patches, the distance between driven and parasitic patches will be evaluated to ensure strong coupling between them. For the second technique, a second layer of FR4 coated with an annealed copper of 0.035mm is added to the substrate. An air gap of 0.04x is used to separate between both FR-4 layers. The design and simulation of the array antenna and the modified structures will be performed using Advanced Design System (ADS) software. Simulation results of each technique will be compared first to basic array antenna simulation results and compared thereafter to each other.