RF Filters with Periodic Passbands for Sparse Fourier Transform-Based Spectrum Sensing
RF Filters with Periodic Passbands for Sparse Fourier Transform-Based Spectrum Sensing
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DOI：
10.1109/jmems.2018.2864177
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发表时间：
2018-10-01
影响因子：
2.7
通讯作者：
Gong, Songbin
中科院分区：
文献类型：
--
作者：
Lu, Ruochen;Manzaneque, Tomas;Gong, Songbin
本文演示了一种具有周期性通带的无源低插入损耗（IL）RF滤波器，能够将频谱从238 MHz稀疏到526 MHz，用于基于稀疏傅立叶变换（SFT）的频谱感知。所展示的周期性滤波器采用具有高品质因数（Qs）、大机电耦合（k（t）（2））和梯形拓扑中的多个等距谐振的LiNbO3横向泛音体声波谐振器（LOBAR）。为了演示周期性滤波器，首先对LOBAR进行建模以准确地预测各种音调的k（t）（2）。所制备的LOBAR在超过10个音调的同时表现出大于1.5%的q和大于30的品质因数（Q.k（t）（2）），这与我们的模型响应一致，并且都是过模谐振器中表现最好的。中心在370 MHz的多频带滤波器，然后已获得与291 MHz的通带跨度，22 MHz的频谱间隔，2 dB的IL，FBW约0.6%，和稀疏化比之间的7和15。超过14只手也实现了约25 dB的带外抑制。具有14个可用周期通带的RF滤波器所展示的出色性能将有助于实现未来基于SET的频谱感测。
This paper demonstrates a passive low-insertionloss (IL) RF filter with periodic passbands and capable of sparsifying the spectrum from 238 to 526 MHz for sparse Fourier transform (SFT)-based spectrum sensing. The demonstrated periodic filter employs LiNbO3 lateral overtone bulk acoustic resonators (LOBARs) with high-quality factors (Qs), large electromechanical coupling (k(t)(2)), and multiple equally spaced resonances in a ladder topology. To demonstrate the periodic filter, the LOBARs is first modeled to predict k(t)(2) of various tones accurately. The fabricated LOBARs show q larger than 1.5% and figure of merits (Q.k(t)(2)) more than 30 for over 10 tones simultaneously, which agree with our modeled response, and are both among the highest demonstrated in overmoded resonators. The multi-band filter centered at 370 MHz has then been obtained with a passband span of 291 MHz, a spectral spacing of 22 MHz, an IL of 2 dB, FBWs around 0.6%, and a sparsification ratio between 7 and 15. An out-of-band rejection around 25 dB has also been achieved for more than 14 hands. The great performance demonstrated by the RF filter with 14 useable periodic passbands will serve to enable future SET-based spectrum sensing.