Spoof surface plasmon polariton band‐stop filter with single‐loop split ring resonators

Abstract

A novel band-stop filter with single-loop split ring resonators (SRRs) is proposed for spoof surface plasmon polaritons (SPPs) at millimeter wave frequencies, achieving a miniaturized size of 0.052λ0×0.278λ0 at its resonant frequency. The SRRs provide both a low-pass response as the rectangular corrugations used in the conventional SPPs and an additional band-stop response induced by the resonance of SRRs. To verify this design, a back-to-back device with two co-planar waveguides as the input and output feeding was fabricated and characterized, the measured S-parameters of which agree well with the simulation. The measured stop band is centered at 49 GHz with a -10-dB bandwidth of 4.1 GHz and a high Q-factor of 93, in which the maximum attenuation is 31 dB. The filter has a low insertion loss of less than 2.8 dB in the pass band. Such approaches may find many applications to achieve compact millimeter wave circuits.

Independently controllable dual band filtering characteristics of a spoof surface plasmonic waveguide employing compound slot structure

“…Also, people focus on the development of controllable plasmonic filters by using SSPPs and coplanar waveguide (CPW) based coupling structure, adjustable dielectric resonators, tunable metamaterial particles as well as tunneling propagations channels [24][25][26][27][28][29][30][31][32][33]. The multichannel composite SSPPs were excited by CPW.…”

Multi frequency multi bit amplitude modulation of spoof surface plasmon polaritons by schottky diode bridged interdigital SRRs

“…Recently, split-ring resonators (SRRs) and complementary SRRs have been investigated to achieve a rejection function of spoof SPPs, such as ultra-wideband and multi-frequency band-stop filters 11 – 14 . To actively modulate the rejection, varactor diodes and Schottky diodes have been integrated with SRR structures, achieving frequency modulation and amplitude modulation, respectively 15 – 21 . These devices have been potentially applied to electrically program spoof SPPs for multifunctional applications.…”

“…Typically, SRRs in spoof SPP band-reject devices use parallel gaps 20 , 21 , as illustrated in Fig. 1 a.…”

“…For multi-frequency modulation, the gap capacitance needs to be swept by changing gap dimensions, e.g., length. Take the SRRs in our previous paper as an example 21 , whose gap width and length are W gap = 3 μm, and L 1 = 135 μm, respectively. Extending L out changes the spoof SPP cut-off frequency so that increasing L in is a better choice.…”

“…The pitch of the in-series SRRs is 0.75 mm. Each spoof SPP unit has two modes: the first is SRR resonant mode 21 , as the dotted solid lines shown, and the latter is spoof SPP mode, as the dotted dash lines shown. It can be clearly seen that all four dispersion curves gradually separate from the curve of light, and then asymptotically arrive at a cut-off frequency.…”