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THE ROLE OF THE DIGITAL COMPUTER IN MICROWAVE ENGINEERING

E.A.N. Whitehead

The purpose of this paper is to consider the uses to whichcomputers have been put in microwave engineering, and to drawwhat lessons and conclusions there may be relevant to theirprofitable use in the future.

Of the capabilities of the brain, it is those notrequiring insight which can be performed by a computer, andof those it is the performance of simple and complexarithmetic which has been applied to microwave engineering.

Microwave engineering is particularly well suited totake advantage of a massive capability to do arithmetic,because the wavelengths involved lie between those in whichoptical approximations give a high accuracy and those inwhich circuit properties may be considered as "lumped". Thecomputer has enabled the precise calculationof a number ofthings, e.g. aerial polar patterns from near field parameters,microwave filters, performance of microwave junctions, etc.This has conferred great benefits, but the ability to obtainaccurate solutions to the numerical problems does not initself lead to an increase of insight into the working ofmicrowave components or stimulate the invention of newcomponents, and it does not appear that this will be thebenefit to be obtained from computers.

The new thing the computer has done is to enable engin-eering design parameters to be stored in abstract form, as analgorithm, and to be changed by a computer into specific formwith a calculated performance when the requirements are madespecific on a data tape. This capability may be used in twoways, as a new method of passing information from the researchengineer to the design engineer and from the design engineerto the drawing office, and also as a necessary pre-requisiteto the simulation of complete radar designs. Thesefacilities could lead to powerful weapons for microwaveengineers, but both require the creation of formalised codesof practice in the input and output formats of programmes.

Mathematical analysis has been used in the past to givetheoretical insight as a basis of further advances, and alsoto provide numerical design data and performance predictionsto such accuracy as was attainable. The latter role hasbeen superceded, but the former is as necessary as ever.To ignore this would lose us the ability to understand theinteractions of the fundamental physical laws which determinethe performance of our engineering design.

E.A.N. Whitehead is Chief Scientist of E.A. Radar Systems