High Gain Wideband Circularly Polarized Microstrip Antenna Array

Abstract

A wideband high gain circularly polarized microstrip antenna (CP MSA) array is presented in this communication. In the proposed CP MSA array, the elements are designed at 3.5 and 5.8 GHz, which are sequentially rotated to form a planar array. The array elements are fed using the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TM_{110}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$TM_{210}$ </tex-math></inline-formula> modes of a center CP MSA. This arrangement achieves an axial ratio (AR) bandwidth of 63.7% (3.25–6.29 GHz) and improves gain over a wide bandwidth. The peak gain of the array is 17.77 dBic with a 3-dB gain bandwidth of 53.9%. The center MSA of the array is fed using four orthogonal printed L-probes with quadrature phase difference. The proposed CP MSA array has an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$|S_{11}|\leq -10$ </tex-math></inline-formula> dB bandwidth of 63.3% (3.32–6.4 GHz).