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Through technical paper, you will demonstrate your skills at communicating to a knowledgeable but not necessarily specialised audience.
You will write a paper based on applying IEEE Std 1597.1 to analyse the level of difference between different aperture lids.
1597.1 was originally formulated for the validation of computational electromagnetics but the core technique, FSV, is domain agnostic and can be used to compare computational electromagnetic data or experimental data. A copy of 1597.1 will be attached in instructions as well as FSV resoults.
This will be written in the style of an IEEE paper, using the IEEE format and not exceeding eight pages.
You will need to understand the standard and how to apply it.
You will also be expected to demonstrate critical insight.
The paper will be judged on:
a. Clarity of presentation and organisation. Is a clear research question posed? Is it valid? Does the paper have an appropriate abstract? Is it properly referenced with an appropriate balance of references? Are the illustrations readable?
b. Technical contribution. Is the work technically correct? Does it make a positive contribution to knowledge? Is it novel in concept or contribution or useful as a tutorial or review contribution? Is the material critically analyzed and appraised in a clear and logical manner?
The lab: ( just to give the overal idea what I have done. Resoults are included as one of the attachments)
Laboratory 3. Measuring the effects of aperture sizes using a mode-stirred reverberation chamber
Objective: To produce empirical evidence to relate the shielding effectiveness of a screen with aperture (s) to the size of the apertures and, if appropriate, the number of apertures.
Background: Apertures in screens are required for a variety of purposes, such as viewing or ventilation. Practice and theory state that the actual shielding effectiveness is proportional to the longest dimension of the aperture and that many small apertures with the same total surface area as a larger single aperture is preferred. Also, the screening effectiveness of the small apertures is inversely proportional to the square root of the number of individual apertures. This project will undertake empirical tests using a reverberation chamber to test these suggestions.
The mode-stirred reverberation chamber is a screened room with a mechanical ‘paddle wheel’ stirrer designed to alter the boundary conditions sufficiently so that a test object placed in the working volume experiences a maximum field strength everywhere across its surface over one revolution of the stirrer. The DMU reverb chamber is housed in Q2.04. You will need to be let in by Hugh, Virpal or myself.
The chamber is excited by an antenna connected to Port 1 of the network analyzer. Port 2 is connected to the test antenna (installed in a cavity in this case). One side of the test cavity can be left open or replaced by a number of ‘lids’. S21 gives a measure of transmission loss, particularly when compared with a reference value.
There are 5 lids (entirely open, entirely closed, large rectangular, slotted, holes (small count), holes (large count)). The last group will repeat the slotted lid measurements for a repeatability test. Each pair of groups (Monday and Wednesday groups) will take turns to help set up a measurement. Data will be shared amongst all groups and each individual will be responsible for processing the data and presenting it themselves – this will require some programming but the language is immaterial. Each data file will have 200 sets of frequency data (one per stirrer position). You will need to extract the highest value at each frequency for all stirrer positions and compare the resulting six data sets with each other in order to draw some conclusions about size versus shielding effectiveness.
As these tests take approximately 6 hours per run, you will be expected to all meet at an agreed time (say 12:15) to set these tests up after the other tests using the network analyzer are completed.
1. Reverberation chamber with transmitting antenna, network analyzer driven by computer.
2. Cavity with interchangeable lids
1. Place cavity in the reverberation chamber approximately 1m off the floor, 1m from the door and midway between the walls. Ensure that the appropriate lid is attached – you may find it helpful to put up a notice, email the group or write on the lids which have been done. (Use a chinagraph, or similar, pencil for this. Not supplied.) You will need a 4mm Hex/Allen key to secure the lid to the box, to ensure a good electrical contact.
2. Ensure the transmitting antenna is connected to port 1 of the network analyzer and the bow-tie antenna in the cavity is connected to port 2.
3. Turn off the network analyser and the computer and turn them back on again (to ensure an easy set-up)
4. Open ‘Vee’ and select ‘Mode Tuned Method’. Set it using the front panel for Start = 500 MHz, Stop = 1500 MHz, 1601 steps.
5. Disconnect the two cables in the chamber from their antennas and connect them together using a suitable in-series adapter.
6. Select the calibrate menu (a drop down under Main) and select Calibrate, response, thru.
7. When this is complete, reconnect the antennas.
8. Ensure the door is closed and press run on the VEE front screen.
9. Following the prompts, save your data in MSc EMC 2010 folder, 200 stirrer steps, Averaging
10. When it is running you may go.
The data will be posted on the module BlackBoard shell sometime in the following few days.
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