Ultra violet radiation controlled non-linear dielectrics

术语光束控制指的是光束的聚焦，以提高到达特定目标的光量，类似于探照灯。但为了增加覆盖范围，豆子被快速调制--探照灯被非常迅速地来回扫视。同样的原理也适用于无线电波和微波。这项提议旨在制造一组可以电子操控的天线，以改善这种聚焦。为了实现这一点，我们需要移相器，移相器是一种可以在施加电压时改变输出信号相位的设备。与目前发射/接收天线没有波束控制的通信系统相比，这将极大地提高它们的性能。由于辐射方向的空间分辨率，降低了发射机的功率，节约了能量，减少了电磁辐射，减少了通道间干扰。相控阵天线发展的主要障碍是含有移相器组的天线控制系统成本较高。这些银行的铁氧体或半导体移相器的成本取决于频段，成本从50美元(L频段)到250美元(Ka频段)不等，甚至更多。考虑到每个天线需要使用20-1000个类似设备来提供所需的天线参数，显然60%-90%的可控波束天线的价格与其控制系统相连。基于铁电薄膜的移相器和其他控制设备可以将单个元件的成本降低到几美元，因为它们的技术简单。然而，铁电器件在脉冲控制电压下表现出剩余极化(将偏置电压降低到零后观察到的滞后现象)和缓慢的弛豫。这一缺点是它们实现的主要障碍，因为它导致可调谐性降低和对脉冲控制电压的时间响应不明确。这项提议的目的是基于一种新的现象开发新的可调谐[铁电]器件。我们和我们的合作者做了一个有趣的观察：紫外光的应用减少了铁电材料的磁滞。这一发现需要进一步的实验。这种效应可以用在全新一代的电子设备上。

The term beam steering means the focussing of a beam of light in order to improve the amount of light reaching a specific target, rather like a searchlight. But to increase the coverage the bean is rapidly modulated - the searchlight is very rapidly swept back and forth. The same principle applies to radio waves and microwaves. This proposal aims to make an array of antennas that can be electronically steered in order to improve this focussing. To achieve this we need phase shifters which are devices that can alter the output signal phase on the application of a voltage. In comparison with current communication systems, in which transmitter/receiver antennas operate without beam steering, this will improve their performance hugely. Transmitter power is reduced, saving energy and reducing electromagnetic radiation, and inter-channel interference is reduced due to the space resolution of radiation directions.The main barrier preventing the development of phased-array antennas is the high cost of the antenna control systems containing banks of phase-shifters. The cost of ferrite or semiconductor based phase-shifters in these banks depends on frequency band and costs from $50 (L-band) up to $250 (Ka-band) and more for one unit. Taking into account the need to use between 20-1000 similar devices for each antenna to provide the required antenna parameters it becomes clear that 60 - 90% of the price of steerable beam antennas is connected with their control system. Phase-shifters and other control devices based on ferroelectric films can reduce the cost of a single element down to a few dollars due to their technological simplicity. However, ferroelectric devices exhibit residual polarization (a hysteresis phenomenon that is observed after decreasing the bias voltage down to zero) and slow relaxation at pulsed control voltage. This disadvantage is the main barrier for their implementation, as it causes a decrease of tunability and an ambiguous time response to the pulsed control voltage. The aim of this proposal is to develop new tuneable [ferroelectric] devices based on a new phenomenon. We and our collaborators have made an interesting observation: a reduction in the hysteresis of ferroelectric materials upon the application of ultra violet light. This discovery requires further experimentation. The effect could be used in an entirely new generation of electronic devices.