Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide

Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide is proposed. Owing to subwavelength confinement, such a filter has advantage in the structure size without sacrificing the performance. The spoof SPP based notch is introduced to suppress the WLAN and satellite communication interference simultaneously. Both the cutoff frequency and the notch frequency are sensitive to the structure parameters, and the cut-off frequency can reach 20GHz. An adiabatic transition relying on gradient hole-size and flaring ground is designed to effectively couple energy into spoof SPP waveguide. The result shows its cut-off frequency of 17.4GHz with the insertion loss better than 3dB during the whole pass-band, while having more than 20dB rejections at 5.36GHz and 9.32GHz with 10dB fractional bandwidth 1.07% and 0.74% respectively to avoid the existing WLAN and satellite communication signals. Due to planar structures proposed here, it is easy to integrate in the microwave integrated systems, which can play an important role in the microwave communication circuit and system. •Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide is proposed.•The spoof SPP based notch is introduced to suppress the WLAN and satellite communication interference.•Both the cutoff frequency and the notch frequency are sensitive to the structure parameters.•The gradient hole and flaring ground are designed to effectively couple energy into spoof SPP waveguide.