Ultra violet radiation controlled non-linear dielectrics

紫外线辐射控制非线性电介质

• 批准号: EP/E044840/1
• 负责人: Neil Alford
• 金额: $ 38.01万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE044840%2F1
• 关键词: Ultra; violet; radiation; controlled; non

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.

术语光束转向意味着光束的聚焦，以提高到达特定目标的光量，而不是像探照灯一样。但是为了增加覆盖范围，豆子被迅速调制-探照灯非常迅速地来回扫过。同样的原理也适用于无线电波和微波。该提案旨在制造一种可以电子操纵的天线阵列，以改善这种聚焦。为了实现这一点，我们需要移相器，这是一种可以在施加电压时改变输出信号相位的器件。与当前的通信系统相比，其中发射机/接收机天线在没有波束转向的情况下操作，这将极大地提高它们的性能。相控阵天线可以降低发射功率，节省能量，减少电磁辐射，并且由于辐射方向的空间分辨率，可以减少信道间干扰。阻碍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的高成本。这些组中基于铁氧体或半导体的移相器的成本取决于频带，并且成本从50美元（L波段）到250美元（Ka波段），并且一个单元的成本更高。考虑到需要为每个天线使用20-1000个类似设备来提供所需的天线参数，很明显，可转向波束天线的价格的60 - 90%与它们的控制系统有关。由于技术简单，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。然而，铁电器件在脉冲控制电压下表现出剩余极化（在将偏置电压降低到零之后观察到的滞后现象）和缓慢弛豫。这一缺点是其实现的主要障碍，因为它导致可调谐性的降低和对脉冲控制电压的模糊时间响应。这项提议的目的是基于一种新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：在紫外光的应用铁电材料的滞后减少。这一发现需要进一步的实验。这种效应可以用于全新一代的电子设备。