RRAC(01)06
Project Title:Investigation into the feasibility of designing frequency selective windows
employing periodic structures.
The following is a summary example of a research proposal:
1. Objectives
1.1 The first objective of this work is to develop the underlying mathematical theory of
material science required to demonstrate the feasibility of utilising periodic structures to
produce radio frequency selective (high pass, low pass, band stop, and band pass)
windows.
1.2 The second objective is to produce a sample series of windows effective at 2.4 GHz
such that an enclosure can be built to house a typical domestic microwave oven. When
the microwave oven is within the enclosure it should be clearly visible through the
enclosure while radiated emissions at 2.4 GHz should be significantly attenuated.
2. Background
2.1 The Agency's mission statement includes the planning and management of radio
services in the UK. In order to provide maximum value for money for spectrum use it is
necessary to address the problem of spectrum pollution from "non Wireless Telegraphy"
sources.
2.2 The use of frequency selective windows has a wide variety of possible applications
that could increase effective spectrum utilisation including optically transparent selective
RF shielding for ISM machinery, “quiet” railway carriages, and wave guide
filters/diplexers. It may be possible to produce frequency/direction selective shields for
portable phone users and multi-user radio sites.
3. Benefits
3.1 The benefits to the Agency of encouraging the development and manufacture of
frequency selective windows will be in the better utilisation of the spectrum by lowering
unnecessary pollution from ISM and “non radio” devices as well as providing a different
approach to site sharing constraints.
3.2 Many new and innovative services share the ISM bands. Conventional RF cages used
around ISM machines are avoided as they also exclude both light and other radio
services producing a poor working environment. If the emissions from ISM machinery
can be significantly reduced then it should be possible to further encourage band sharing
with other services that could not coexist at present.
3.3 The use of optically transparent frequency selective shields at radio sites could result
in increased antenna placement flexibility and front to back performance along with
reduced visual impact.
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4. Statement of Work
4.1 Before any work begins the contractor will agree with the Agency a project work plan
showing the deliverables and their time scales. The contractor in order to facilitate
management of the project should provide a hard copy of this work plan.
4.2 Perform a literature search to compile all the existing knowledge on this topic and
develop the underlying theory to demonstrate the theoretical feasibility of the project. The
theory should allow for the design of low pass, high pass, band stop, and band pass
windows of variable and predictable characteristics.
4.3 Investigate and develop the material science required to develop both visually
transparent and visually opaque window tiles.
4.4 Apply the theory developed in 4.2 to design a periodic structure suitable for producing
visually transparent window tiles at least 10 cm X 10 cm that will significantly attenuate
emissions from microwave ovens operating around 2.4 GHz.
4.5 Produce enough of the window tiles in 4.4 to produce an enclosure suitable for
housing a small domestic microwave oven.
4.6 Demonstrate to the satisfaction of the Radio Agency that the enclosure significantly
reduces the emissions from a microwave oven while allowing other radio services used
inside it to operate unhindered. The Agency laboratory at Whyteleafe may provide
assistance with the measurements involved if required.
4.7 Propose work for further investigations by which it may be possible to optimise the
characteristics of this technology for commercial applications thereby contributing to the
reduction of unnecessary spectrum pollution and the more efficient design of radio sites.
5. Deliverables and Timetables
5.1 The following deliverables are required within the given time scales, these relate to
the tasks outlined in the Statement Of Work (SOW) above.
5.2 Deliverable 1
Agreement with the Agency of the plan in para 4.1 to show how the contractor intends to
achieve the objectives and deliverables of the project within the time scales required. The
plan should also show what contingencies are available should unforeseen difficulties
arise in the work. This should take place within 1 week of the contract start date.
5.3 Deliverable 2
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An interim report on the investigations detailed in paras 4.2 and 4.3 to include all relevant
information obtained and a detailed and comprehensible account of the underlying theory
of both the periodic structures and the material science involved.
This report should be available within 12 weeks of the contract start date.
5.4 Deliverable 3
An interim report detailing the mathematical and material design as in para 4.4 of four
visually transparent sample tiles capable of operating as loss pass, high pass, stop band,
and band pass, filters at 2.4 GHz respectively. The exact characteristics of the tiles should
be confirmed with the Agency’s Project Manager.
This report should be available within 20 weeks of the contract start date.
5.5 Deliverable 4
A demonstration of the microwave oven enclosure as detailed in para 4.6. This enclosure
should be constructed from a number of either the band stop or low pass filter tiles as
agreed with the Agency’s Project Manager.
5.6 Deliverable 5
A final report submitted in draft form . This should at least:
- incorporate all interim reports;
- detail the work carried out during the project;
- detail and reference the methodologies used;
- include all results obtained when undertaking the tasks required in the Statements Of
Work;
The final report will be based on the draft report and will include any amendments to the
draft resulting from discussions between the contractor and the Agency. The final report
should also be submitted in an electronic form suitable for placing on the Agency’s web
site.
This deliverable is required at the termination of the project or within 28 weeks of the
contract start date, whichever is the sooner, unless agreed otherwise by the Agency in
writing.
Dissemination of the content of the work, or any results, to any third parties may only
take place with the prior written consent of the Agency. It may also form part of the
project that the contractor may be required to present the results of the project to an
audience of persons invited by the Agency and submit a draft paper, or papers, on the
work suitable for presentation to international standards committees.
6. Payment
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6.1 Payments will be related to those Deliverables identified in section 5 above and the
project proposal from the contractor should clearly identify these within the project.
Invoices should be submitted for payment only on the satisfactory completion of each
deliverable.
7. Duration
7.1 The project should run for a period not exceeding 28 weeks commencing as early as
possible after award of the contract.
7.2 For guidance purposes only, the Agency estimates that this contract should not
involve more than 100 person days of work.
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