To paraphrase a quotation of American author James Redfield, the history of fields of endeavor such as antennas and propagation is not just the evolution of technology, but it is the evolution of thought. That is why it is important that organizations such as the IEEE and the Antennas and Propagation Society have History Committees and an IEEE Milestone program and that the editor-in-chief of this magazine supports this column.
I have been asked several times why I am interested in the history of our field, and my answer is usually that you do not really know your field unless you delve deeper into how it came about and why we use the techniques we do. Several members of our Society are enthusiastic about the history of electromagnetics, specific antennas, propagation modeling, and application of numerical methods. My hope is that we can encourage a greater interest in the history of particular techniques and why certain potentially powerful methods were not adopted until later. An awareness of history in our field gives a better sense of awareness, of others’ work and of workers in our field, its continuity, and the obvious advantage of not repeating mistakes of the past.
One example of this is the moment method. As a numerical technique, it has been around since the 1940s when it was developed by Yamada and reported more widely in the early 1950s [1]. There are various ways of formulating the method in terms of shape functions and order of moments. The first record of the use of moment methods for antennas was by Barzilai in 1955 [2], when he used a variation of the method to solve Hallen’s equation for linear antennas. Others followed with variations of the method. Harrington authored a landmark paper in 1967 on matrix methods in field problems [3]. In this paper, Harrington introduced an appropriate moment method formulation and gave solutions for a charged conducting plate and radiation from wires of arbitrary shape.
Figure 1 shows two segments n and m of wire scatterers from the paper by Harrington; ${n}^{+}$ and ${n}^{-}$ denote the two ends of segment n. The distances from the ends and the midpoints are generally ${r}_{{n}^{+}{m}^{-}}$, which is the distance from the top end of segment n and bottom end of m. This was put together in much more detail in his book on moment methods, which appeared in 1968 [4]. This book was cogently written and very influential. I know from experience it caused considerable interest in my first year as a research student in 1971 as I attended a seminar given by a researcher who had visited Harrington and was adopting his methods for arrays. The advantages of Harrington’s formulation of the moment method were plain to see, and the computation time was modest. In this instance, it took the development of computers, a suitable formulation of the method, and programs for the computers to achieve the full potential of the method. Since then, the moment method has remained a major tool in the tool kit of many antenna engineers.
Figure 1. Two segments m and n of a wire scatterer in Harrington’s moment method formulation described in 1967 [3].
Other numerical methods that had been developed in the early part of the 20th century were also adopted about this time, too. This came about because of the relative ease of computation in the 1970s. As well as moment methods, finite elements, and other subdomain methods, computer packages based on these techniques were developed in the ten to fifteen years following. As an aside, the subdomain methods took a little longer to become commercial as there was the critical problem of achieving a suitable method of discretization, but that is another story. This is an example of a method or approach ahead of its time, and it needed developments in fields outside the original development. The advantage of history is that it shows that sometimes the further development of an idea or concept may need to be looked for in other fields.
Another example of having a grasp of history is to realize stimulation of development may come not from within our field but outside it. There are many instances of this. From my experience, I was part of the transition of reflector antennas and feeds from single to dual polarization [5]. This requirement came about to double the channel capacity and throughput in both terrestrial microwave links and satellite communications. Another more recent example has been the need for wideband arrays to provide flexibility for next generation communications. The concept of the current sheet introduced by Wheeler [6] has been rediscovered after about 50 years [7] and used in this challenging area along with metamaterials, which also are based on well-known techniques from periodic structures that are well known in other fields [8].
An appreciation of history enables us to better understand the work of others and enables us to comment on proposed advances. The benefit of an improved approach that moves our technology forward will be readily apparent from an appreciation of history for reviews, conference attendance, and purchasing new products. This goes to support another comment on history that it is like having the rear vision mirror providing input to our advance in a forward direction.
[1] H. Yamada, “An approximate method of integration of the laminar boundary-layer equation,” Rep. Res. Inst. Fluid Eng., vol. 4, pp. 27–42, 1950. (Appl. Mech. Rev., vol. 5, no. 488).
[2] G. Barzilai, “On the input construction of thin antennas,” Trans. IRE Prof. Group Antennas Propag., vol. 3, no. 1, pp. 29–32, Jan. 1955, doi: 10.1109/TPGAP.1955.5720408.
[3] R. F. Harrington, “Matrix methods for field problems,” Proc. IEEE, vol. 55, no. 2, pp. 136–149, Feb. 1967, doi: 10.1109/PROC.1967.5433.
[4] R. F. Harrington, Field Computation by Moment Methods. New York, NY, USA: Macmillan, 1968.
[5] T. S. Bird, Fundamentals of Aperture Antennas and Arrays: From Theory to Design, Fabrication and Testing. Chichester, U.K.: Wiley, 2016.
[6] H. A. Wheeler, “Simple relations derived for a phased-array antenna made of an infinite current sheet,” IEEE Trans. Antennas Propag., vol. 13, no. 4, pp. 506–514, Jul. 1965, doi: 10.1109/TAP.1965.1138456.
[7] I. Tzanidis, J. P. Doane, K. Sertel, and J. L. Volakis, “Wheeler’s current sheet concept and Munk’s wideband array,” in Proc. IEEE Symp. Antennas Propag., Chicago IL, USA, Jul. 2012, pp. 1–2, doi: 10.1109/APS.2012.6349119.
[8] C. Kittel, Introduction to Solid State Physics, 3rd ed. New York, NY, USA: Wiley, ch. 9, 1968.
Digital Object Identifier 10.1109/MAP.2023.3280837