In this chapter, a comprehensive review of recent contributions in the field of fully reconfigurable RF/microwave multi-notch filters is presented. These circuits are understood to be key components in future RF front-ends for wideband receivers to efficiently mitigate intentional and unintentional narrowband interference [18]. Specifically, tunable implementations for planar technologies are described in which the adaptive multi-notch filtering action is co-integrated with the wideband signal preselection process in a single dual-function RF filter. These filtering devices exploit different operating principles such as frequency-controllable circuit networks and coupled-resonator arrangements, whose advantages and disadvantages are discussed. Further, state-of-the-art mobile form factor high-Q filters for ultra-narrowband interference suppression based on mixed-technology acoustic-wave lumped-element resonators are also reported. A brief summary of future trends in this area is also provided at the end of the chapter.

Chapter Contents:

• 10.1 Introduction
• 10.1.1 Wideband receiver architectures for radar and communication systems
• 10.1.2 Narrowband interference in wideband receivers
• 10.2 Case study: impact of narrowband interference on a wideband radar receiver
• 10.2.1 Coherent FMCW radar
• 10.2.2 Impact and mitigation of CW interference on FMCW radar
• 10.2.3 Integration of tunable notch filters in the receiver front-end
• 10.3 Spectrally agile RF/microwave multi-notch filters
• 10.3.1 Filter design for agile interference rejection
• 10.3.2 Filter design based on a coupled-resonator arrangement
• 10.3.3 Filter design based on hybrid acoustic-wave/lumped-element resonators
• 10.4 Looking ahead: future trends
• 10.5 Conclusions
• References

Inspec keywords: interference suppression; microwave filters; radar signal processing; acoustic resonator filters; adaptive filters; notch filters; radar receivers

Other keywords: intentional narrowband interference mitigation; adaptive multinotch filtering action; adaptive RF multiinterference suppression; frequency-controllable circuit networks; planar technologies; unintentional narrowband interference mitigation; mixed-technology acoustic-wave lumped-element resonators; communication receivers; single dual-function RF filter; RF front-ends; wideband radar; coupled-resonator arrangements; ultra-narrowband interference suppression; microwave multinotch filters; mobile form factor high-Q filters; wideband signal preselection process; fully reconfigurable RF filters

Subjects: Filtering methods in signal processing; Acoustic wave devices; Radar equipment, systems and applications; Electromagnetic compatibility and interference