Third-Order General Chebyshev <i>LC</i> Bandpass Filters With Two Transmission Zeros in Triplet

As spectrum source is limited, more and more emerging wireless technologies require complex filtering responses for efficient spectrum allocation. In this article, direct synthesis technique (DST) we proposed is utilized to synthesize third-order general Chebyshev LC wideband bandpass filters with two transmission zeros (TZs). The TZs can be flexibly shifted, so that filter responses are easily controlled to meet different requirement. These filters are realized in the forms of crossing coupling or triplet, and each element value is analytically determined by the DST. Element values can be easily and flexibly adjusted for engineering realization. At the same time, both source and load impedances can also be flexibly adjusted, so that these filters can act as impedance transformers at the same time. These triplets could also act as the building blocks for modular synthesis of higher order filters.