Fourier Transforms and Directional Couplers (Correspondence)

The excellent review of Bolinder on the applications of Fourier transforms in wave theory, particularly the section on "Coupling of Waves," suggested that the readers of these Transactions might also be interested in some related work performed by this writer some time ago. A report on this work contains a section on the use of Fourier integral and series methods for directional coupler design. In connection with directional couplers, this letter also can be considered as noting a further addition to the useful bibliography of Schwartz. Although not widely distributed, the aforementioned report has been available since late 1947 in the Document Room of the Research Laboratory of Electronics at the Massachusetts Institute of Technology as No. SPE-239. It should be emphasized that this letter is not intended to start a controversy as to who did what first, but rather to bring to the readers\´ attention a report of possible interest.