TY - JOUR
T1 - Extended passband bandstop filter cascade with continuous 0.85-6.6-GHz coverage
AU - Naglich, Eric J.
AU - Lee, Juseop
AU - Peroulis, Dimitrios
AU - Chappell, William J.
N1 - Funding Information:
Manuscript received October 15, 2011; accepted October 26, 2011. Date of publication December 05, 2011; date of current version December 30, 2011. This work was supported by BAE Systems under the Tunable Notch Filter Program and by the Defense Advanced Research Projects Agency (DARPA) under the Purdue Evanescent-Mode Cavity Filter Study Program. The work of E. J. Naglich was supported by the Department of Defense (DoD) under the National Defense Science and Engineering Graduate Fellowship (NDSEG) Program.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/1
Y1 - 2012/1
N2 - This paper presents a cascade of tunable bandstop filters with a wide spurious-free upper passband, which is completely spanned by the tuning range of the notch responses. A collection of resonators is shown to be able to provide bandstop filter responses over a 7.8 to 1 tuning range. By using spurious-free upper passband aperture-coupled cavity bandstop filters, multiple resonators, each with octave tuning, can cover a multioctave frequency range in a cascade. It is shown that the upper passband of this type of filter is limited by the reactance of the coupling apertures, which produce an unwanted in-band resonance unless designed properly. The details of this design process are explained and used to design a six-resonator bandstop filter cascade that is able to provide a bandstop filter response with up to 55 dB attenuation over the continuous band of 0.85-6.6 GHz. Through dynamic allocation of the cascade circuit's transmission zeros, one-, two-, three-, and four-pole bandstop filter responses of variable bandwidth can be realized over different frequency ranges, offering numerous bandwidth-attenuation level tradeoff combinations.
AB - This paper presents a cascade of tunable bandstop filters with a wide spurious-free upper passband, which is completely spanned by the tuning range of the notch responses. A collection of resonators is shown to be able to provide bandstop filter responses over a 7.8 to 1 tuning range. By using spurious-free upper passband aperture-coupled cavity bandstop filters, multiple resonators, each with octave tuning, can cover a multioctave frequency range in a cascade. It is shown that the upper passband of this type of filter is limited by the reactance of the coupling apertures, which produce an unwanted in-band resonance unless designed properly. The details of this design process are explained and used to design a six-resonator bandstop filter cascade that is able to provide a bandstop filter response with up to 55 dB attenuation over the continuous band of 0.85-6.6 GHz. Through dynamic allocation of the cascade circuit's transmission zeros, one-, two-, three-, and four-pole bandstop filter responses of variable bandwidth can be realized over different frequency ranges, offering numerous bandwidth-attenuation level tradeoff combinations.
KW - Filters
KW - microwave filters
KW - passive filters
KW - tunable filters
KW - tunable resonators
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U2 - 10.1109/TMTT.2011.2175245
DO - 10.1109/TMTT.2011.2175245
M3 - Article
AN - SCOPUS:84855459624
SN - 0018-9480
VL - 60
SP - 21
EP - 30
JO - IEEE Transactions on Microwave Theory and Techniques
JF - IEEE Transactions on Microwave Theory and Techniques
IS - 1
M1 - 6095352
ER -