Patent attributes
An integrated balanced-filter which acts as a matching network, a balun and an extracted-pole bandpass filter is disclosed. The balanced-filter includes an unbalanced terminal, a first balanced terminal and a second balanced terminal, a first resonator connected to the unbalanced terminal, a second resonator connected to the first balanced terminal, and a third resonator connected to the second balanced terminal. The second resonator is positively coupled to the first resonator, and the third resonator is negatively coupled to the first resonator, which provides a balun function and a bandpass-filtering function. The balanced-filter further includes extracted-pole notch filters, which can introduce a transmission zero and implement matching network. The balanced-filter can be implemented in a multi-layered substrate, thereby reducing the size of the balanced-filter.
