Filters are fundamental building blocks in the analog based band section of a wireless transceivers. In both receiver (RX) and transmitter (TX) sides, the use of an analog filter allows to reduce the dynamic range requirements of the following stages. In this webinar, three different approaches will be discussed. The first will be the class of pipe filters where the fundamental kT C limit is somehow overcome by high pass shaping the noise in the filter pass band. In the second part of the webinar, the concept of adaptivity will be analyzed by presenting a low pass filter able to automatically adapt its filter transfer function upon the strength of the interferers at its input. The webinar will end with a discussion about passive switch capacitor filters. In this section it will be introduced a new continuous time model for switched capacitor circuits able to characterize the capability of time variant systems to implement non reciprocal network with only passive element. This characteristic will be also the key to the implementation of complex conjugate poles in passive switched capacitor structure.