Abstract: Nonreciprocal components are exclusively achieved today through magnetic materials to break time-reversal symmetry. These components suffer from the drawbacks inherent to ferrite media, namely bulkiness, high cost,incompatibility with integrated circuit fabrication processes, difficulty in circuit integration. With regard to the issues associated with the nonreciprocal components, the aim of this paper is to break time-reversal symmetry, achieve nonreciprocal electromagnetic wave propagation and realize magnetic-free integrated nonreciprocal filter based on spatiotemporal modulation. Frequency reconfigurability can be achieved by controlling the DC voltages loaded to the time-modulated resonators. The proposed nonreciprocal filter integrates the property of filter and oscillator, which permits the directional propagation of in-band signals and suppresses out-band interference, showing exotic
functionality.

Key words: filter, frequency reconfigurability, nonreciprocity, spatiotemporal modulation