Modelling & Design

By about 1990, PO was responsible for a microwave oven and food modelling project at SIK (The Swedish Food Institute) using the first commercially available FDTD software (Curlsol, UK). Later, he also used the Hewlett-Packard (now Agilent) FEM software HFSS, but the state-of-the-art in software and computer performance did not become sufficiently useful and cost-effective until about 1997. PO constructed three crucial benchmarking scenarios, using his previous knowledge about some particular weaknesses of the FEM and FDTD principles. These scenarios were subsequently tested by at least four vendors of the then commercially available software packages. The Polish QWED company came out as a strong winner, after just having presented the first version of their later prizewinning Quickwave FDTD software. As a result, QWED sold several licenses to Microtrans clients and other entities active in microwave heating technology. PO invested many months in learning efficient ways of using this new tool, and even more time in developing means towards understanding microwave field theory and constructing application methods of the software in areas such as applicator optimisation, choke design and magnetron simulation. He has several times said that this long period of investment in use and applications of the QW3D software was his best professional investment ever.

Some modelled designs are shown at http://www.qwed.eu; go to Examples and then Microwave Heating. Click below to get some other examples, from courses and similar presentations.  Another illustration of the software and its uses is this QWED leaflet.

The use of modelling has drastically increased the rate of inventive work, with typically up to three new patent applications per year being filed for the last several years.'

Other modelling examples:

• About deviations between modelling and experimental results (3 kB)

• The proximity effect
  

• The edge overheating effect   Description in a two-page PDF file is available here (1,3 MB). 

• The “exploding egg” effect, etc.  Description in a three-page PDF file is available here (2,2 MB, modified 2006–03–28).

• Microwave modelling allows the extraction of “microwave movies”, i.e. pictures illustrating how the fields vary over a cycle of the 2450 MHz microwave oscillation. In many cases, the movies allow an improved understanding of particular behaviours of applicators. Click here for an example (1,5 MB).
      Note: © Microtrans AB; the files may be reproduced only with reference to the source