Wide-Angle Scanning Phased Array Using an Efficient Decoupling Network

Abstract

The active impedance of each element in a phased array changes substantially with scan angle due to mutual coupling. Therefore, a key challenge in the design of wide-angle scanning phased array is to achieve wide-angle impedance matching (WAIM). In this communication, an efficient decoupling network is developed to reduce the mutual coupling between adjacent elements for this purpose. A complete scattering matrix analysis of the decoupling network is given and the design procedure is summarized. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${1} \times {16}$</tex-math></inline-formula> linear microstrip phased array has been designed and fabricated for experimental verification. Good agreement is obtained between measured and simulated results. The measured mutual coupling between adjacent elements is reduced to lower than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$- {35}\; \text{dB}$</tex-math></inline-formula> at the center frequency. Due to the reduced mutual coupling, the array can experimentally scan to 66° with a gain reduction of only 3.04 dB.