Yang Lingling, Liu Haihong, Cai Bin, Wu Ling, Cheng Yongzhi
School of Electronic Engineering, Hubei Engineering Research Center for Intelligent Detection and Identification of Complex Parts, Wuhan Vocational College of Software and Engineering (Wuhan Open University), Wuhan, 430205, P. R. China.
School of Information Science and Engineering, Engineering Research Center for Metallurgical Automation and Detecting Technology Ministry of Education, Wuhan University of Science and Technology, Wuhan, 430081, P. R. China.
Sci Rep. 2024 Nov 5;14(1):26722. doi: 10.1038/s41598-024-77705-y.
In this paper, a novel compact bandpass filter (BPF) with a wide out-of-band rejection is proposed. It can achieve broadband characteristics by combining hollow bowtie-type spoof surface plasmon polaritons (SSPPs) with complementary H-type defected grounded structures (DGSs) through aperture coupling. Compared with the conventional SSPP unit cells, the hollow bowtie-type structure exhibits much better slow-wave characteristics. The introduced slant antenna type port-coupling can produce a very strong high-performance rejection outside the high frequency stopband. Simulation results show that the SSPPs-DGS-based BPF has an excellent band pass characteristics in a broadband range with - 3dB fractional bandwidth of 43.5% at center frequency f of 2.04 GHz. The return loss in the passband is better than - 12 dB. Furthermore, because of the multiple transmission zeros generated in upper-stop-band, the designed BPF has an extremely strong out-of-band rejection of -40dB from 1.5 f to 4 f (f is the center frequency). The designed SSPPs-DGS-based BPF is fabricated by conventional printed circuit board (PCB) technology with a compact size of only 0.68λ*0.34λ (λ is the wavelength at the center frequency). The measured results have a good agreement with the simulation ones, which verifies the rationality and feasibility of the design. The miniaturized wideband BPF with broad out-of-band rejection may make it has good application prospect in the new generation microwave communication field.
本文提出了一种具有宽带外抑制特性的新型紧凑型带通滤波器（BPF）。它通过将空心领结型类表面等离子体激元（SSPPs）与互补H型缺陷接地结构（DGSs）通过孔径耦合相结合，可实现宽带特性。与传统的SSPP单元相比，空心领结型结构具有更好的慢波特性。引入的倾斜天线型端口耦合在高频阻带外可产生很强的高性能抑制。仿真结果表明，基于SSPPs-DGS的BPF在宽带范围内具有优异的带通特性，在中心频率f为2.04 GHz时，-3dB分数带宽为43.5%。通带内回波损耗优于-12dB。此外，由于在上阻带中产生了多个传输零点，所设计的BPF在1.5f至4f（f为中心频率）范围内具有-40dB的极强带外抑制。所设计的基于SSPPs-DGS的BPF采用传统印刷电路板（PCB）技术制造，尺寸紧凑，仅为0.68λ*0.34λ（λ为中心频率处的波长）。测量结果与仿真结果吻合良好，验证了设计的合理性和可行性。具有宽带外抑制的小型化宽带BPF在新一代微波通信领域可能具有良好的应用前景。
