Broadband artistic antenna array composed of circularly-polarized Wang-shaped patch elements

A broadband circularly-polarized antenna array with unidirectional radiation has been proposed. The 2 × 2 array is considered as an artistic array composed of Chinese character" Wang-shaped patches, arranged in a rhombic lattice. The subarray exhibits broadband performance with a 3-dB axial-ratio bandwidth of 62%, 15-dB return-loss bandwidth of 57.6%, maximum gain of 12 dBic and a 9-dB gain bandwidth of 29.5%. The antenna array features a compact profile of 1.25λo × 1.88λo × 0.14λo at 2.5 GHz. For the design of a broadband circularly polarized array, spacing between elements remains a crucial parameter that critically affects the array performance. However, method and justification in determining an optimized spacing are rarely reported in literature. As a new contribution, this paper presents a study in this aspect.