Furthering Electromagnetic Architecture of Buildings - An International Travel Application

电磁频谱是一种有限的资源，频率复用是必不可少的，特别是在移动通信频段。信号在建筑环境中的传播是出了名的复杂，但建筑是一个可以实施措施来修改其电磁结构的环境。划分为办公室的多人居住商业建筑原则上可以在内部进行电磁屏蔽，以帮助频率重复使用，而大型，更开放的结构，如剧院，可以通过适当的外墙结构进行屏蔽。现在，特别是在新建筑中，在墙壁内安装铝箔背衬层是一种常见的做法，作为防火措施或绝缘目的。适当的筛选可以大大减少同信道干扰，我们在奥克兰的同事指出，仅仅增加10或15dB的信噪比就可以将中断概率降低一个数量级或更多。在其他频率，通过屏幕访问是必要的，特别是在紧急服务频段——在英国是400MHz，但在新西兰显然低至75MHz。在EPSRC和国家警务改进局资助的一个非常成功的项目中，我们一直专注于频率选择表面（FSS）在建筑环境中的应用，重点是移动通信中使用的长波操作。例如，在采用最小阵列元件数量的情况下，旨在提供这种紧急访问的长波FSS基于简单的方环路槽单元。另一种方法是减少阵列单元的大小，这一概念导致了与奥克兰大学无线电系统小组的密切合作，该小组在测量和模拟建筑物中的信号传播方面拥有丰富的经验。虽然FSS是一项成熟的技术，但它在移动频率下还不是很好地理解，因为移动频率下阵列是有限的，元件可能是高度卷曲的，层间距很小，房间尺寸与工作波长相当。FSS设计在移动频段具有挑战性，因为它们在分数比方面相差很大。我们已经在奥克兰的一个办公室类型的测试室内安装了一个由高度复杂的元素组成的新颖的两层FSS。这项工作正在进行中，以EPSRC先前资助的工作为基础。本申请旨在为研究人员提供资金，使他们能够在两个不同的场合前往奥克兰，研究三个相关的主题：1。研究FSS在小孔径安装时的效果；表征高入射角下FSS的性能；在一个专门建造的办公室类型的房间中评估壁挂式FSS对无线计算机网络性能的影响。

The electromagnetic spectrum is a finite resource and frequency reuse is essential particularly in the mobile communications bands. Signal propagation in the built environment is notoriously complex but buildings are an environment where measures can be implemented to modify their electromagnetic architecture. Multiple occupancy commercial buildings, partitioned into offices, can in principle be electromagnetically screened internally to assist frequency reuse, and large, more open structures such as theatres can be shielded by suitable construction of the outer walls. It is common practice now, particularly in new buildings, to install aluminium foil backed layers within walls, as a fire precaution measure or for insulation purposes. Suitable screening can greatly reduce co-channel interference and our colleagues in Auckland have pointed out that an increase in the signal-to-interference ratio of just 10 or 15dB can decrease outage probability by an order of magnitude or more. At other frequencies access through the screen is necessary, especially at the emergency services band - at 400MHz in the UK, but apparently as low as 75MHz in New Zealand. In a very successful project funded by EPSRC and the National Policing Improvement Agency, we have been focussing on the application of Frequency Selective Surfaces (FSS) to the built environment with the emphasis on operation at the long wavelengths used in mobile communications. For example, a long-wavelength FSS intended to provide this emergency access while employing a minimum number of array elements has been based on simple square loop slot elements. An alternative approach is to reduce the array unit cell size, and this concept has led to a close collaboration with the Radio Systems Group at the University of Auckland who have extensive experience measuring and modelling the propagation of signals in buildings. Although FSS is an established technology, it is not well understood at mobile frequencies where the arrays are finite, elements may well be highly convoluted, layer separations are electrically small and room dimensions are comparable to the operating wavelengths. FSS design is challenging at mobile bands as they are far apart in fractional ratio terms. We have already installed in an office-type test room in Auckland a novel two layer FSS composed of highly convoluted elements. This work is ongoing, building on the work previously funded by the EPSRC. This application is for funding to enable the investigators to travel to Auckland on two separate occassions to work on three related topics: 1. to study the effect of FSS when mounted in small apertures, 2. to characterise FSS performance for high angles of incidence, 3. to assess the effect of wall mounted FSS on Wireless Computer Network performance in a specially built office-type room.