翻译练习：Electricity Can Be Transmitted Through The Air(3)

微波中继设备

The relays, which are passive devices that do not use any power, work like lenses, refocusing the microwave beam and sending it on its way with minimal transmission losses. They can also steer it, if necessary, in a new direction. This means that transmitter and receiver need not necessarily be in line of sight of one another.

中继设备是一些被动设备，它们不使用任何电力，工作的原理就和透镜一样，重新聚焦微波束，然后重新发送这些电力，几乎没有传输的损失。如果需要，它们还可以调整方向，甚至是一个新的方向。这意味着传输器和接收器之间没有必要在视界内保持直线。

合成材料

Metamaterials are composites containing tiny amounts of conductive metals and insulating plastics arrayed in a manner that causes them to interact with electromagnetic radiation such as microwaves in particular ways. They are already employed in so-called cloaking devices that help warships and military arcraft hide from radar. But they can also be used in a receiving antenna, to convert electromagnetic waves into electricity more efficiently.

超材料是包含导电金属的微小颗粒与绝缘塑料混合而成的合成材料，其微粒的排列导致它们与微波之类的电磁辐射以特殊的方式发生相互作用。它们早已被应用于所谓的隐身设备，帮助军舰和军用飞机从雷达上隐身。它们也可以用作接收天线，更高效地把电磁波转换为电力。

激光幕

Broadcasting powerful microwaves through the air does carry risks. Similar waves are, after all, the means by which microwave ovens heat what is put into them. Emrod says brief exposure to its beams should not cause any harm to people or animals as the power density is relatively low. Nevertheless, to avoid accidents the beams will be surrounded by so-called laser curtains. These are low-power laser beams that are not themselves harmful. But if a curtain is twitched by the interposition of things such as birds or low-flying helicopters (which in New Zealand are used to round up sheep), that interruption will be detected instantly and the microwave transmission temporarily cut. Batteries at the receiving end will fill in during any outages.

通过空气广播高能微波束的确会带来风险。毕竟，微波炉加热放入其中食物的方法就是类似的波。埃姆罗德公司表示短时间暴露于他们的微波束中并不会对人或动物造成任何伤害，因为功率较低。然而，为了避免意外，微波将用所谓的激光幕包裹，激光幕是一种低能激光束，它们自身不会造成伤害。但是如果有鸟类或低空直升机（在新西兰用来圈羊）之类的东西扰动了激光幕，就会被立即检测到，微波传输器就会被临时切断。在停电期间，电池将在接收端顶替供电。