In this paper, a wide band ridge gap waveguide (RGW) fan beam antenna with low side lobe level (SLL) is presented making use of parabolic offset reflector concept in antenna geometry. In the proposed topology, in contrast to TEM based RGW horn, the amplitude distribution across the antenna aperture can be easily controlled. Furthermore, thanks to intrinsic feature of parabolic reflector in generating plane wave front, the phase distribution uniformity across the proposed antenna aperture is better than that of the RGW horn. These two facts allow the proposed topology to provide lower SLL compared to the RGW horn. A prototype of the proposed structure is designed and fabricated. Simulation and measurement results also show that wider operating bandwidth compared to the RGW horn can also be achieved using this topology. For the designed sample, the impedance bandwidth of 41% with -20 dB ≤ SLL ≤ - 15 dB and gain of 11.8-15.5 dBi is achieved. Results show that the proposed topology can be a good candidate for realization of high gain wide band RGW fan beam antennas with low SLL.

中文翻译：

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基于抛物面反射器原理的低旁瓣宽带脊隙波导（RGW）扇形波束天线

本文利用抛物线偏移反射器概念在天线几何中提出了一种具有低旁瓣电平（SLL）的宽带脊隙波导（RGW）扇形波束天线。在提出的拓扑中，与基于TEM的RGW喇叭相比，可以轻松控制天线孔径上的幅度分布。此外，由于抛物面反射器在产生平面波前中的固有特征，所提出的天线孔径上的相位分布均匀性要比RGW喇叭更好。与RGW喇叭相比，这两个事实使建议的拓扑可以提供较低的SLL。设计并制造了所提出结构的原型。仿真和测量结果还表明，与RGW喇叭相比，使用此拓扑还可以实现更宽的工作带宽。对于设计的样品，-20 dB≤SLL≤-15 dB时，阻抗带宽为41％，增益为11.8-15.5 dBi。结果表明，所提出的拓扑结构可以很好地实现具有低SLL的高增益宽带RGW扇形波束天线。