On a lumped element three-branch 3-dB coupler with Butterworth and Chebyshev characteristics

Three-branch 3-dB quadrature couplers comprised of one-quarter wavelength transmission lines and their dual circuits comprised of three-quarters wavelength transmission lines are transformed into lumped element circuits using network equivalents to transmission line segments. The frequency characteristics of the lumped element circuits, which are the equivalents of distributed constant branch line couplers with Butterworth and Chebyshev characteristics, are found to be wider in frequency bandwidth and more symmetrical about the center frequency than those presented in previous papers.