RF-Power-Activated and Signal-Tracking Tunable Bandstop Filters

Two new classes of RF-power-dependent tunable bandstop filters that share a common filter topology are presented in this paper. RF-power-activated tunable bandstop filters transition from a resonant-allpass response to a bandstop response in the presence of a high-power RF signal, allowing for optimum use of the spectrum when used to solve interference issues in a receiver. Signal-tracking tunable bandstop filters automatically tune their center frequencies to that of a high-power RF signal, eliminating the need for complex sensing and control systems. The theory and design as well as laboratory prototypes are presented for both. The RF-power-activated tunable bandstop filter prototype achieves a minimum allpass-state insertion loss of 2.5 dB and a bandstop-state attenuation of greater than 50 dB. The signal-tracking tunable bandstop filter prototype attenuates a high-power signal by greater than 33 dB over a frequency range of 251–304 MHz.

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

[2]  I. Hunter,et al.  Electronically Tunable Microwave Bandpass Filters , 1982 .

[3]  A. Guyette,et al.  Intrinsically Switched Varactor-Tuned Filters and Filter Banks , 2012, IEEE Transactions on Microwave Theory and Techniques.

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

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

[7]  Eric J. Naglich,et al.  Frequency-Selective Limiters Utilizing Contiguous-Channel Double Multiplexer Topology , 2016, IEEE Transactions on Microwave Theory and Techniques.

[8]  D. Peroulis,et al.  Switchless Tunable Bandstop-to-All-Pass Reconfigurable Filter , 2012, IEEE Transactions on Microwave Theory and Techniques.

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

[10]  Ian C. Hunter,et al.  Tunable combline bandstop filter with constant bandwidth , 2009, 2009 IEEE MTT-S International Microwave Symposium Digest.

[11]  John D. Adam,et al.  Mitigate the Interference: Nonlinear Frequency Selective Ferrite Devices , 2014, IEEE Microwave Magazine.

[12]  Roger D. Pollard,et al.  Design of absorptive microwave filters using allpass networks in a parallel-cascade configuration , 2009, 2009 IEEE MTT-S International Microwave Symposium Digest.

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