Microwave Journal 50 Year Retrospective Series: A Few Personal Remarks on the Evolution of Computational Electromagnetics

Introduction

I remember reading the Microwave Journal as a graduate student in the Microwave Lab at McGill University in Montreal in 1969. Then, as now, the Microwave Journal was filled with articles, observations and product information on microwave and wireless hardware, although today there are also articles on microwave software.

The graduate students around me were also building hardware – remote sensing devices, communication devices, antennas, and the like – but my project was different: I was writing a computer program to model microwave fields.

Computers in 1969 were still primitive. This is an odd statement since the electronic computer was over two decades old by that time. Yet the basic procedure to program a computer had been unchanged for years: in 1969, one still used punched paper cards to write a computer program and submitted this card deck to a central computer facility. The memory available on the mainframe computer was miniscule: the IBM 360 mainframe computer, figure 1 at McGill had 128 Kbytes of available main memory. I remember limiting my computations to solve about a 100 X 100 matrix; anything larger was likely to cause a program overflow.

Figure 1. Researchers (not the author) with the IBM 360 Mainframe Computer

Since memory was small, the early work in computational electromagnetics focused on simple algorithms. Chief among these was the finite difference method that was simple to program and avoided explicitly storing the coefficient matrix. K. Lee had published the finite difference time domain algorithm in 1966. This was all changed by the two pioneering giants of computational electromagnetics, Roger Harrington and Peet Silvester. Professor Harrington developed the method of moments procedure for solving the integral form of Maxwell’s equations, while Professor Silvester developed the finite element method for solving the differential form of Maxwell’s equations.

I was fortunate to join Peet Silvester’s research group in 1969 as his third graduate student and the first one to work on finite element methods for microwave engineering.