Design of a rotated feeding wide-angle scanning phased array with circular polarization

Abstract

Since the birth of the phased array technology, phased array antennas have been widely used in communication, navigation, electronic warfare and other fields. For the reason that circular polarization antennas have advantages of inhibition of the rainfall depolarization effect and anti-multipath reflection effect, circular polarization antenna chosen as the array elements designed to form a phased array with high performance in this paper. This antenna element, excited through a single feed point, is composed of a square patch in the middle and four circular patches with different radii. Thus, the circular polarization and the wide beam performance of the proposed antenna element are achieved by adjusting the size of the circular patches. To obtain a wide angle scanning function, a 4 × 4 rotated feeding antenna array with this proposed microstrip antenna element is designed. Every four adjacent elements, i.e., 2 × 2 elements, form a subarray in the proposed array. An element in the subarray is regarded as the reference one and the positions of the other three elements deviate from it of 90°, 180° and 270°, respectively. Firstly, the other three elements are fed with the compensation phases of 90°, 180° and 270° to make the cross polarization between the elements to be offset. Secondly, the phase differences are added to control the scan angle in scanning planes. The microstrip antenna array realizes a ±45° wide angle scan in the φ = 0° and φ = 90° planes with the gain more than 15 dB and the axial ratio within the scope of the main lobe width less than 3 dB.