A compact, single- feed, dual band, circularly polarized annular ring patch antenna coupled to a cross slot is proposed in this letter for GPS-aided GEO-augmented navigation (GAGAN) receivers covering L band, centered at 1176.45 MHz (L5) and 1575.42 MHz (L1) frequencies. The antenna consists of two annular rings configured by two small strips, which is coupled to a cross slot in the ground plane for gain enhancement. Circular polarization in both the bands is produced by introducing perturbations in outer annular ring and two orthogonal strips in the center space of inner annular ring. The proposed CP antenna radiates LHCP in both the desired frequencies. Two shorting pins are introduced near the feed to improve impedance matching. The simulated and measured reflection coefficient, gain, circular polarization, and axial ratio are in accord with each other. The measured 10 dB bandwidth is 2.7% (1168–1200 MHz) for the L5 and 2.5% (1560–1600 MHz) for L1. The AR bandwidth below 3 dB for the designed antenna is 1.5% (1156–1174 MHz) for L5 and 1% (1556–1572 MHz) for L1.

中文翻译：

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用于 GPS 辅助 GEO 增强导航接收器的双频段圆极化环形贴片天线


本信中提出了一种紧凑、单馈电、双频带、圆极化环形贴片天线耦合到交叉槽，用于 GPS 辅助 GEO 增强导航 (GAGAN) 接收器，覆盖 L 频带，中心频率为 1176.45 MHz (L5) 和1575.42 MHz (L1) 频率。该天线由两个小带构成的圆环组成，该圆环耦合到接地平面中的十字槽以增强增益。两个频带中的圆偏振是通过在外环和内环中心空间中引入两个正交条带的扰动而产生的。所提出的 CP 天线在两个所需频率下辐射 LHCP。在馈电附近引入两个短路引脚以改善阻抗匹配。模拟和测量的反射系数、增益、圆偏振和轴比相互一致。测得的 10 dB 带宽对于 L5 为 2.7% (1168–1200 MHz)，对于 L1 为 2.5% (1560–1600 MHz)。设计天线低于 3 dB 的 AR 带宽对于 L5 为 1.5% (1156–1174 MHz)，对于 L1 为 1% (1556–1572 MHz)。