A series of compact rejection filters based on the interaction between spoof SPPs and CSRRs.
We propose a method to synthesize several band-rejection filters by etching split-ring resonators (SRRs) on the transmission line for spoof surface plasmon polaritons (SPPs), which is made of double-side or single-side corrugated metal strips. From dispersion relations, the corrugated strips can support spoof SPP modes when the operating frequency is less than the cutoff frequency. The electric field component perpendicular to the strip surface of the SPP modes can excite the complementary SRRs (CSRRs), leading to resonant modes preventing the SPP propagation near the resonant frequencies. Using this principle, single-frequency rejection filters, double-frequency rejection filters, and broad band-stop filters with bandwidth of 1.5 GHz have been designed and fabricated using the single- and/or double-side corrugated strips. Both measured results and numerical simulations demonstrate the excellent filtering characteristics of all design, which are in good agreements. The isolation of all filters can be less than -20 dB, and even reach to -38 dB at rejection frequencies. The proposed rejection and stop-band filters give important potentials to develop integrated plasmonic functional devices and circuits at microwave and terahertz frequencies.
State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China.|Synergetic Innovation Center of Wireless Communication Technology, Southeast University, Nanjing 210096, China.
Qian
Q
Zhang
State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China.|Synergetic Innovation Center of Wireless Communication Technology, Southeast University, Nanjing 210096, China.
Hao Chi
HC
Zhang
State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China.|Synergetic Innovation Center of Wireless Communication Technology, Southeast University, Nanjing 210096, China.
Jia Yuan
JY
Yin
State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China.|Synergetic Innovation Center of Wireless Communication Technology, Southeast University, Nanjing 210096, China.
Bai Cao
BC
Pan
State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China.|Cooperative Innovation Centre of Terahertz Science, No.4, Section 2, North Jianshe Road, Chengdu 610054, China.
Tie Jun
TJ
Cui