Nellen Simon, Lauck Sebastian, Schwanke Garrit, Deumer Milan, Kohlhaas Robert B, Liebermeister Lars, Schell Martin, Globisch Bjoern
Opt Express. 2021 Mar 15;29(6):8244-8257. doi: 10.1364/OE.416844.
In future wireless communication networks at terahertz frequencies, the directivity and the beam profile of the emitters are highly relevant since no additional beam forming optics can be placed in free-space between the emitter and receiver. We investigated the radiation pattern and the polarization of broadband continuous-wave (cw) terahertz emitters experimentally and by numerical simulations between 100 GHz and 500 GHz. The emitters are indium phosphide (InP) photodiodes with attached planar antenna, mounted on a hyper-hemispherical silicon lens and integrated into a fiber-pigtailed module. As both packaging and material of the emitter was identical for all devices, similarities and differences can be directly linked to the antenna structure. We found that the feeding point structure that connects photodiode and antenna has a large influence on the radiation pattern. By optimizing the feeding point, we could reduce side lobes from -2 dB to -13 dB and narrow the 6dB beam angle from ±14° to ±9° at 300 GHz.
在未来的太赫兹频率无线通信网络中，发射器的方向性和波束轮廓至关重要，因为在发射器和接收器之间的自由空间中无法放置额外的波束形成光学器件。我们通过实验和数值模拟研究了100GHz至500GHz频段宽带连续波（cw）太赫兹发射器的辐射方向图和极化特性。发射器是带有平面天线的磷化铟（InP）光电二极管，安装在超半球形硅透镜上，并集成到光纤尾纤模块中。由于所有器件的发射器封装和材料都相同，因此相似性和差异可以直接与天线结构相关联。我们发现连接光电二极管和天线的馈电点结构对辐射方向图有很大影响。通过优化馈电点，我们可以将300GHz时的旁瓣从-2dB降低到-13dB，并将6dB波束角从±14°缩小到±9°。
