Adaptive microstrip antenna arrays for wireless security systems

The paper presents an adaptive technique to create multiple nulls to suppress multiple jammers. It is demonstrated to be effective and efficient. Computer simulations for a linear array of 32 elements have shown that the optimization technique can create wide as well as deep nulls, which correspond well to jammer widths and strengths. The paper also discusses several microstrip arrays with different feed systems that have been successfully employed in wireless security systems. By applying the optimization technique to the microstrip arrays of 8 elements, it is shown that deep nulls are created in the difference pattern as well as the sum pattern. In ail cases the SIR improves substantially and converges quickly, requiring not more than four iterations.