Multifrequency Transformer With Arbitrary Frequency and Real Impedance Transform Ratio

In this letter, the modified small reflection theory is further extended to the design of a multifrequency transformer with an arbitrary frequency and real impedance transform ratio, by mapping small reflection coefficients between 2N + m- and 2N-section transformers. Due to the introduced mapping, the dominated equation of the 2N + m-section transformer is reduced to that of the 2N-section transformer without introducing an additional matching frequency among the desired frequency ratio range. For verification, a penta-frequency transformer is implemented and measured. The measured results agree closely with the calculated and simulated results.