A Design Method for Chebyshev Transmission－Line Quasi-Low-Pass Filters Having Different

For the case where the internal resistance of the power source and the load resistance differ､a design method for a Chebyshev-type transmission-1ine low-pass filter which functions as an impedance transformer and a low-pass filter is described.The filter considered have a pair of attenuation poles at the finite frequency in the stopband, and the connecting unit elements contribute to the attenuation response.The Chebyshev function used for lumped element networks is developed, the Chebyshev function for a transmission-line low-pass fi1ter with a finite attenuation corresponding to the terminating resistance ratio for the zero frequency and having a pair of poles at the finite frequency in the stopband is derived, and a method for determination of the characteristic function fulfilling the specification is shown.After the pole location is chosen, the characteristic function of the transmission-line lowpass filter under consideration can be determined easily by use of the conventional Chebyshev polynominals of the first and second kind. For an eighth degree network, the network synthesis is carried out for a range of the terminating resistance ratio R from 2 to 6, and consequent variation of the network element values is shown.