Adaptive multi-band negative-group-delay RF circuits with low reflection
Institute of Electrical and Electronics Engineers (IEEE)
Two classes of frequency-reconfigurable multi-band negative-group-delay (NGD) circuit networks that feature low-input-power-reflection capabilities are reported. They consist of lossy-complementary-diplexer architectures, in which the NGD properties are obtained within the stopband regions of their lossy multi-band bandstop-filter (BSF) channel. Their complementary lossy multi-band bandpass-filter (BPF) branch absorbs in its terminating resistor the RF-input-signal energy that is not transmitted by the lossy multi-band BSF channel within its stopbands. In this manner, the input-reflectionless/absorptive behavior is realized. The theoretical foundations of the devised lossy-multi-band-BSF-based NGD structures using a coupling-routing-diagram formalism and single-to-multi-band admittance transformations are described. For the first-order case as illustration, guidelines for the synthesis in the bandpass frequency domain are provided. Furthermore, the extension of these multi-band NGD approaches to higher-order and in-series-cascade multi-stage realizations for more-general and wider-band NGD patterning, as well as to two-port/symmetrical designs, is shown. In addition, the conception of multi-functional passive components with NGD characteristics, such as wide-band BPFs and power directional couplers with embedded NGD regions, is also addressed. For experimental-demonstration purposes, an electronically-reconfigurable microstrip prototype of a two-stage-in-series-cascade dual-band NGD circuit is manufactured and measured.
Absorptive filter , Bandpass filter (BPF) , Bandstop filter (BSF) , Bandwidth , Complementary diplexer , Coupler , Couplers , Lossy filter , Microstrip , Microstrip circuit , Multi-functional circuit , Negative group delay (NGD) , Planar circuit , Propagation losses , Radio frequency , Reconfigurable circuit , Reflectionless filter , Resistors , Resonant frequency , RF analog signal processing , Tunable circuit , Wide-band filter
Gómez-García, R., Muñoz-Ferreras, J.-M. and Psychogiou, D. (2021) 'Adaptive multi-band negative-group-delay RF circuits with low reflection', IEEE Transactions on Circuits and Systems I: Regular Papers. doi: 10.1109/TCSI.2021.3055416
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