A wide variety of desirable antenna beam patterns can be synthesized by optimal excitation and phasing of the HE ₁₁ and HE ₁₂ modes in scalar corrugated feedhorns. However, the bandwidth of such two-mode horns is often limited by modal dispersion. In this paper we introduce a class of low dispersion, two-mode feedhorns that can operate, in some cases, over operating bandwidths of 40-50%. We provide example designs that include horns with high coupling efficiency to: 1) a pure HE ₁₁ mode for single-mode excitation of corrugated pipe transmission lines; 2) a LG ₀₀ and LG ₀₂ combination for radiometry, with narrow beams; 3) a pure Laguerre Gaussian LG ₀₀ mode for quasi-optical instrumentation with constant phase centers; 4) a constant gain antenna for uniform illumination with frequency; 5) Airy patterns or “top hat” patterns for radar or communications applications, designed to maximize aperture efficiencies when used with larger reflect or lens antennas. More generally, we show methods to generate and phase multiple ${\text{HE}}_{1n}$ modes, to synthesize symmetric output beams at any desired frequency or gain.

中文翻译：

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用于雷达、通信、辐射测量和准光学的宽带波纹馈电喇叭

通过标量波纹馈电喇叭中HE ₁₁和 HE ₁₂模式的最佳激励和定相，可以合成各种理想的天线波束方向图 。然而，这种双模喇叭的带宽通常受到模态色散的限制。在本文中，我们介绍了一类低色散、双模馈电喇叭，在某些情况下，它可以在 40-50% 的工作带宽上工作。我们提供的示例设计包括具有高耦合效率的喇叭： 1) 用于波纹管传输线的单模激励的纯 HE _11模式；2) 用于辐射测量的 LG ₀₀和 LG ₀₂组合，具有窄光束；3) 纯拉盖尔高斯 LG ₀₀具有恒定相位中心的准光学仪器模式；4) 恒定增益天线，用于频率均匀照明；5) 用于雷达或通信应用的 Airy 模式或“顶帽”模式，设计用于在与更大的反射或透镜天线一起使用时最大化孔径效率。更一般地，我们展示了生成和相位倍数的方法 ${\text{HE}}_{1n}$模式，以合成任何所需频率或增益的对称输出光束。