Realization of Tunable Periodical Differential Transmission Lines on Silicon

Differential transmission lines (DTL) can be synthesized as a chain of identical 4-Port unit cells (UC). These DTL are interesting to use for either matching the circuits or for realizing small resonators in filters or oscillators. One very interesting aspect is the tunability of such a transmission line. Tunability means the ability to tune the electrical length and the characteristic impedance by applying appropriate voltage. In this paper, we introduce a new method to realize the tunability of these transmission lines thru magnetic coupling. This tunable Periodical DTL (PDTL) provides highly interesting applications for silicon MMICs.