The Journal of Korean Institute of Electromagnetic Engineering and Science (한국전자파학회논문지)

The Korean Institute of Electromagnetic Engineering and Science (한국전자파학회)
권호 표지

Design of 4-Pole Low Noise Active Bandpass Filter Improving Amplitude Flatness of Passband

통과대역 평탄도를 개선한 4단 저잡음 능동 대역통과 여파기 설계

  • Published : 2004.06.01
Download PDF
⟨ Previous Next ⟩

Abstract

An active capacitance circuit which employs series feedback network for the implement of negative resistance and low noise operation is analyzed in depth and its application to low noise active RF BPF's is discussed. Whereas many authors reported a lot of circuits that embody negative resistance circuit most of them have concerns for the equivalent resistance and reactance value at the center frequency. In this case, it could be possible to face a problem that the negative resistance circuit becomes unstable, or have poor flatness in passband because of insufficient forecast for the negative resistance values as the frequency goes higher or lower. In this paper, we extracted the exact equivalent values of this circuit and analyzed the RF characteristics with the varying the values of active devices and feedback circuits and presented the method that the flatness of passband can be improved. We have designed a 4-pole active BPF, which has the bandwidth of 60 ㎒, 0.67 ㏈ insertion loss, 0.3 ㏈ ripple, and noise figure of 3.0 ㏈ at 1.99 ㎓ band.

저잡음 특성과 함께 부성 저항과 수동 캐패시턴스의 특성을 보이도록 설계된, 직렬 피드백 회로를 이용한 FET능동 캐패시턴스 회로를 심도 있게 분석하였고, 이를 저잡음 능동 대역통과 여파기에 적용하였다. 부성저항을 이용한 마이크로파 대역 능동 여파기의 설계방식은 비교적 여러 차례 소개되었으나, 원하는 주파수에서 적절한 부성저항 성분을 구현하는 데에는 아직 어려움이 있으며, 이로 인한 능동 회로의 안정성 저하와 대역내 평탄도 증가 등으로 인해 실제 상용화에는 다다르지 못하고 있다. 이들 문제를 해결하고 실제 상용화에 이르기 위해서는 부성저항 회로의 세밀한 분석이 필요하며, 이를 이용한 부성저항 성분의 제어를 가능하도록 해야 한다. 이에 본 논문에서는 능동 캐패시턴스 회로의 부성저항 성분을 분석하였고, 또한 BPF의 통과대역의 평탄도를 개선할 수 있는 방법을 제시하였다. 제작된 4단 대역통과 여파기는 중심주파수 1.99 ㎓에서 60 MHz의 대역폭을 가지며, 0.67 ㏈ 삽입손실, 0.3 ㏈ 이내의 대역내 평탄도와 3.0 ㏈의 잡음 지수 특성을 보였다.

Keywords

References

  1. 2003 IEEE MTT-S Int. Microwave Symp. Dig. v.3 A novel bandqass filter using active capacitance Jae-Ryone Lee;Young-Hoon Chun;Sang-Won Yun
  2. IEEE Trans. Microwave Theory Tech. v.MTT-38 no.9 Microwave active filters based on coupled negative resistance method C.Y.Chang;T.Itoh
  3. IEEE Microwave and Guided Wave Letters v.3 no.3 Active varactor tunable bandpass filter S.R.Chandler;I.C.Hunter;J.G.Gardiner https://doi.org/10.1109/75.205668
  4. IEEE Trans. Microwave Theory Tech. v.MTT-49 no.5 Noise performance of resistance compensated microwave bandpass filters-theory and experiments Kwok-Keung M. Cheng;Hil-Yee Chan
  5. IEEE Trans. Microwave Theory Tech. v.MTT-43 no.9 Miniature microwave filters for communication systems I.C.Hunter;S.R.Chandler;D.Young;A.Kennerley
  6. Int JRF and Microwave v.CAE 12 Recent advances in microwave active filter design, Part 2: tunable structures and frequency control techniques L.Billonnet;B.Jarry;S.E.Sussman-Fort;E.Rius;G.Tann'e;C.Person;S.Toutain
  7. IEEE Trans. Microwave Theory Tech. v.MTT-47 no.8 Frequency-selective MEMS for miniaturized low-power communication device C.T.C.Nguyen
  8. 1998 IEEE MTT-S Int. Microwave Symp. Dig. v.1 MEMS and Si-micromachined components for low-power, high-frequency communications systems l.P.B.Katehi;G.M.Rebeiz;C.T.C.Nguyen
  9. 1999 IEEE MTT-S Int. Microwave Symp. Dig. v.3 Millimeter-wave micromachined tunable filters H.T.Kim;J.H.Park;Y.K.Kim;Y.Kwon
  10. 2003 IEEE MTT-S Int. Microwave Symp. Dig. v.3 3-D silicon micromachined RF resonator K.M.Strohm;F.J.Schmuckle;O.Yaglioglu;J.F.Luy;W.Heinrich
  11. International Electron Devices Meeting 2002. IEDM '02. Dig. Advancement of MEMS into RF-filter applications R.Aigner;J.Ella;H.J.Timme;L.Elbrecht;W.Nessler;S.Marksteiner
  12. ADS2002, Advanced Design System Agilent Technology