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In this paper, a wideband wide-beam circularly polarized (CP) antenna excited by sequential rotation feeding technology is proposed. The antenna is primarily constituted of a loop radiating element and a reactive impedance structure (RIS) cavity. The loop radiator is stimulated by a curved feeding line through six slots etched on the ground, thereby enabling the antenna to achieve broadband performance. In order to achieve a wide 3-dB axial-ratio beamwidth (ARBW), as well as exhibit less effect on the half-power beamwidth (HPBW), a RIS cavity is introduced beneath the loop radiator. To validate the proposed structure, a prototype was constructed and subjected to a series of tests. The results indicate that the bandwidth of the antenna is 187.5% (0.11 ∼ 3.41 GHz) under a 10-dB return loss. In the frequency band spanning from 1.07 GHz to 2.1 GHz, the AR is less than 3 dB, yielding a bandwidth of 64.98%. Furthermore, at the frequencies of 1.2 GHz, 1.5 GHz, and 1.8 GHz, the proposed antenna demonstrates wide beam characteristics, with the HPBW exceeding 90◦, and the 3-dB ARBW within 162◦ 224◦ . In addition, since no extra feeding network is utilized, the antenna is compact in size. [ABSTRACT FROM AUTHOR]

In this paper, a dual-band circularly polarized (CP) antenna with wide axial ratio and gain beamwidths is proposed for high-precision BDS applications. The radiator consists of four groups of dipoles, eight metal columns, and a reflector. The half-power beamwidth (HPBW) can be effectively increased by bending a portion of the dipole into an arc and loading a series of metal columns on the ground. Besides, a reactive impedance structure (RIS) is inserted and serves as a reflector to improve the axial ratio beamwidth (ARBW) and obtain unidirectional radiation. At the same layer of the dipoles, a four-feed network is presented to provide stable quadrature-phase excitation. For validation, the designed antenna is manufactured, where the overall size is 0.48λ × 0.48λ × 0.12λ. Measurement results suggest that the proposed antenna is capable of operating efficiently within the frequency range of 1.17-1.22 GHz (4.2%) and 1.5-1.65 GHz (9.5%), which covers BDS B1 and B2 bands. Moreover, at four main planes, the measured 3-dB ARBW/HPBW are more than 121°/121° and 150°/198° at 1.207 GHz and 1.561 GHz, respectively. Considering that the proposed CP antenna exhibits wide overlapped beamwidth and small size, it is conducive to high-precision positioning in BDS applications. [ABSTRACT FROM AUTHOR]