Electronic Science and Technology ›› 2019, Vol. 32 ›› Issue (1): 42-46.doi: 10.16180/j.cnki.issn1007-7820.2019.01.009

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Design and Implementation of an Electrically Tunable Filter with High Suppression

LIU Lele1,LIU Lan2,SHI Yu1,WU Zhilin3,HU Yue1,WEN Jie1   

  1. 1. School of Microelectronics and Solid-state Electronics,University of Electronic Science and Technology of China, Chengdu 610054,China
    2. The 29th Institute of China Electronic Technology Group Corporation,Chengdu 610036,China
    3. The 30th Institute of China Electronic Technology Group Corporation,Chengdu 610041,China
  • Received:2017-12-23 Online:2019-01-15 Published:2018-12-29
  • Supported by:
    National Natural Science Fund of China(61471086)


For the demand of wide frequency band, low loss and high external restriction in the front preselection of superheterodyne receiver, a filter was increased to suppress the spurious band behind the LC electrically tunable filter with inductance coupling method in the article, designing an electrically tunable filter on account of 20~800 MHz . Actual test showed that in the tuning range, insertion loss of the filter was less than 1.5 dB, 1 dB bandwidth was about 20%~30%, VSWR of input and output ports were less than 1.5, suppression on the second harmonic frequency was more than 40 dBc. The suppression on the spurious band was increased more than 40 dBc in the second frequency and more than 30 dBc in the third harmonic frequency after applying this filter. All these benefited to the filter with the intermediate frequency suppression, mirror frequency suppression, the reverse leakage of vibration suppression, and so on.

Key words: superheterodyne receiver, wide frequency range, low insertion loss, high external restriction, electrically tunable filter, spurious band

CLC Number: 

  • TN61