Reconfiguring the World: Adaptive-Transfer-Function and Multi-Band Filtering Devices for Emerging Wireless Systems

Next-generation multi-purpose wireless-communications (e.g., 5G) and multi-mode remotesensing systems demand highly-versatile RF front-ends capable of supporting them. As a result, a lot of interest has recently been detected in the development of advanced high-frequency electronics featuring increased levels of spectral adaptivity and multi-band operation. In particular, a considerable attention is being dedicated to the design of fully-reconfigurable single/multi-band RF bandpass filtering devices as key blocks to perform the adaptive-signalband-selection process required by these systems. On the other hand, the ever-growing saturation of the radio-spectrum resource has led to critical electromagnetic-coexistence scenarios between the plurality of co-located RF systems that exploit it. In this case, the availability of fully-controllable multi-notch RF filters to suppress spectrally- and power-agile interferers is very desirable. The purpose of this seminar is to present an overview of recent contributions in the research field of RF filtering devices with highly-reconfigurable and multiband transfer function. This includes both multi-passband and multi-bandstop components for multi-channel-selection and multi-interference-mitigation applications, respectively. Furthermore, their operational and design foundations, as well as a rich variety of experiment demonstrators in different bands and high-frequency technologies (e.g., planar, 3-D, lumped-element, acousticwave, and integrated ones), will be shown.