Furthering Electromagnetic Architecture of Buildings - An International Travel Application

电磁频谱是一种有限的资源，特别是在移动通信频段，频率重用是必不可少的。信号在建筑环境中的传播是出了名的复杂，但建筑物是一个可以实施措施来修改其电磁架构的环境。原则上，被划分为办公室的多用途商业建筑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，可以通过合适的外墙结构来屏蔽。现在的普遍做法是，特别是在新建筑中，作为防火措施或出于绝缘目的，在墙壁内安装铝箔背衬。适当的屏蔽可以极大地减少同频道干扰，我们在奥克兰的同事指出，仅增加10db或15db的信干比就可以将中断概率降低一个数量级或更多。在其他频率，通过屏幕接入是必要的，特别是在紧急服务频段-在英国是400兆赫，但在新西兰显然低至75兆赫。在EPSRC和国家警务改进局资助的一个非常成功的项目中，我们一直专注于将频率选择性表面(FSS)应用于建筑环境，重点是在移动通信中使用的长波长运行。例如，打算在使用最少数量的阵列单元的同时提供这种紧急接入的长波长FSS已经基于简单的方形环槽单元。另一种方法是减小阵列单元的大小，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，后者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，但在移动频率下还不能很好地理解它，在移动频率处，阵列是有限的，元件可能非常复杂，层间距很小，房间尺寸与工作波长相当。FSS的设计在移动频段是具有挑战性的，因为它们在分数比方面相距很远。我们已经在奥克兰的一个办公型测试室安装了一个由高度复杂的元件组成的新型双层FSS。这项工作是在EPSRC以前资助的工作的基础上进行的。这项申请是为了使调查人员能够在两个不同的情况下前往奥克兰，就三个相关主题开展工作：1.研究安装在小孔中的FSS的影响，2.表征大入射角下的FSS性能，3.在专门建造的办公型房间中评估壁挂式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.