On the design of a diplexer having Butterworth characteristics

In a recent paper, V. Belevitch (see Int. J. Circuit Theory Appl., vol.15, no.1, p.51-60, 1987) discusses the design of a diplexer using filter pairs with Butterworth characteristics, where the separation of the desired frequency bands are accomplished by using filters connected either in parallel or in series. Instead of using complementary techniques to modify the ordinary filters, an analytical technique for the design of the diplexer is proposed.<>