Dual-frequency admittance property of two sections transmission-line and application

In this paper, an interesting dual-frequency behavior of admittance of two sections transmission-line (TSTL) terminated into a real impedance is reported. Furthermore, it is shown that the Monzon two-section dual-frequency impedance transformer is a special case of the reported technique and can be derived from this property itself. In addition, the discovered property leads to a modified dual-frequency L-type matching network that provides better transformation-ratio than the Monzon transformer. As an application, a dual-frequency T-junction power divider has been fabricated on FR4 substrate to show the practical utility of the presented theory. The simulated and measured results clearly exhibit good performance.