Theory and Design of Frequency-Tunable Absorptive Bandstop Filters

Absorptive bandstop filters are a relatively new class of bandstop filter, which are able to achieve very high levels of stopband rejection with relatively low-quality-factor resonators, in contrast to typical reflective bandstop filters, whose stopband rejections are limited by the quality factors of their resonators. This paper performs an in-depth theoretical and practical analysis of this class of filter, presenting design principles for reducing the sensitivity to process variation, increasing the tuning range over which the filters can operate with good performance, and addressing the practical non-ideal effects of implementation, such as frequency variation of couplings and quality factor. Four varactor-tuned microstrip bandstop filters are presented to verify the presented theory. They illustrate the design tradeoffs between selectivity and tuning range, choice of coupling topology and tuning range, and show the benefits and drawbacks of cascading stages to create higher-order filters.

[1]  Jr. R. Wyndrum.  Microwave filters, impedance-matching networks, and coupling structures , 1965 .

[2]  Michael J. Lancaster,et al.  Cross-coupled microstrip hairpin-resonator filters , 1998 .

[3]  D.R. Jachowski,et al.  Compact, frequency-agile, absorptive bandstop filters , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[4]  A.C. Guyette,et al.  Perfectly-matched bandstop filters using lossy resonators , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[5]  W.D. Yan,et al.  Compact Tunable Bandstop Filter Integrated with Large Deflected Actuators , 2007, 2007 IEEE/MTT-S International Microwave Symposium.

[6]  Ian F. Akyildiz,et al.  A survey on spectrum management in cognitive radio networks , 2008, IEEE Communications Magazine.

[7]  C. Rauscher,et al.  Frequency-agile bandstop filter with tunable attenuation , 2009, 2009 IEEE MTT-S International Microwave Symposium Digest.

[8]  Andrew C. Guyette,et al.  Sub-octave-tunable microstrip notch filter , 2009, 2009 IEEE International Symposium on Electromagnetic Compatibility.

[9]  Gabriel M. Rebeiz,et al.  Compact Low-Loss Tunable $X$-Band Bandstop Filter With Miniature RF-MEMS Switches , 2010, IEEE Transactions on Microwave Theory and Techniques.

[10]  Gabriel M. Rebeiz,et al.  Lumped-Element Fully Tunable Bandstop Filters for Cognitive Radio Applications , 2011, IEEE Transactions on Microwave Theory and Techniques.

[11]  Douglas R. Jachowski.  Octave tunable lumped-element notch filter , 2012, 2012 IEEE/MTT-S International Microwave Symposium Digest.

[12]  Trevor Snow,et al.  Tunable high quality-factor absorptive bandstop filter design , 2012, 2012 IEEE/MTT-S International Microwave Symposium Digest.

[13]  Dimitrios Peroulis,et al.  Tunable bandstop filter with a 17-to-1 upper passband , 2012, 2012 IEEE/MTT-S International Microwave Symposium Digest.

[14]  Eric A. M. Klumperink,et al.  Tunable N-Path Notch Filters for Blocker Suppression: Modeling and Verification , 2013, IEEE Journal of Solid-State Circuits.

[15]  Dimitrios Peroulis,et al.  Octave tunable lumped-element notch filter with resonator-Q-independent zero reflection coefficient , 2014, 2014 IEEE MTT-S International Microwave Symposium (IMS2014).

[16]  Akash Anand,et al.  Substrate-integrated octave-tunable combline bandstop filter with surface mount varactors , 2014, 2014 IEEE International Wireless Symposium (IWS 2014).

[17]  Gabriel M. Rebeiz,et al.  0.7–1.0-GHz Reconfigurable Bandpass-to-Bandstop Filter With Selectable 2- and 4-Pole Responses , 2014, IEEE Transactions on Microwave Theory and Techniques.

[18]  Dimitrios Peroulis,et al.  High-Q intrinsically-switched quasi-absorptive tunable bandstop filter with electrically-short resonators , 2014, 2014 IEEE MTT-S International Microwave Symposium (IMS2014).

[19]  Dimitrios Peroulis,et al.  Single/multi-band Wilkinson-type power dividers with embedded transversal filtering sections and application to channelized filters , 2015, IEEE Transactions on Circuits and Systems I: Regular Papers.

[20]  Dimitrios Peroulis,et al.  Tunable high-isolation W-band bandstop filters , 2015, 2015 IEEE MTT-S International Microwave Symposium.

[21]  Kari Stadius,et al.  Analysis and Design of N-Path Filter Offset Tuning in a 0.7–2.7-GHz Receiver Front-End , 2015, IEEE Transactions on Circuits and Systems I: Regular Papers.

[22]  Dimitrios Peroulis,et al.  Design and implementation of an intrinsically-switched 22–43 GHz tunable bandstop filter , 2016, 2016 IEEE 17th Annual Wireless and Microwave Technology Conference (WAMICON).

[23]  Eric J. Naglich,et al.  Short-Through-Line Bandstop Filters Using Dual-Coupled Resonators , 2016, IEEE Transactions on Microwave Theory and Techniques.