Chained function filters

In this work we describe a new family of filter transfer functions called Chained Function (CF) filters that have the property of having a reduced sensitivity to manufacturing errors. The reduction is achieved by controlling the position of the return loss zeros while maintaining a given maximum ripple in the inband response. The formulation is given in detail together with an example of application confirming the achieved reduction. The CF family of filters can be used effectively to extend the range of applicability of state-of-the-art tuningless implementations toward higher frequencies or narrower bandwidths.