Twofold Reflectionless Filters of Inverse-Chebyshev Response With Arbitrary Attenuation

Khalaj‐Amirhosseini, Mohammad; Taskhiri, Mohammad Mahdi

doi:10.1109/tmtt.2017.2716940

Cited by 48 publications

(25 citation statements)

References 6 publications

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“…Multiple identical single-stage circuits can be cascaded to improve the passband selectivity at the cost of multiplied circuit size and number of components. Duplexer-style one-port absorptive lowpass filters with arbitrary transfer functions are designed using complementary susceptance cancellation in [11]. The same idea is used to develop microstrip one-port absorptive multiband bandpass and bandstop filters [12], filtering power dividers [13], reconfigurable BPFs [14], and multiplexers [15].…”

Section: Introductionmentioning

confidence: 99%

High-Order Dual-Port Quasi-Absorptive Microstrip Coupled-Line Bandpass Filters

Liu

2020

IEEE Trans. Microwave Theory Techn.

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In this paper, we present the first demonstration of distributed and symmetrical all-band quasi-absorptive filters that can be designed to arbitrarily high orders. The proposed quasi-absorptive filter consists of a bandpass section (reflective-type coupled-line filter) and absorptive sections (a matched resistor in series with a shorted quarter-wavelength transmission line). Through detailed analysis, we show that the absorptive sections not only eliminate out-of-band reflections but also determine the passband bandwidth. As such, the bandpass section mainly determines the out-of-band roll-off and the order of the filter can be arbitrarily increased without affecting the filter bandwidth by cascading more bandpass sections. A set of 2.45-GHz 1-, 2-, and 3-pole quasi-absorptive microstrip bandpass filters are designed and measured. The filters show simultaneous input and output absorption across both the passband and the stopband. Measurement results agree very well with the simulation and validate the proposed design concept.

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Section: Introductionmentioning

confidence: 99%

High-Order Dual-Port Quasi-Absorptive Microstrip Coupled-Line Bandpass Filters

Liu

2020

IEEE Trans. Microwave Theory Techn.

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“…Reflectionless filters can also be realized using complementary diplexer architectures. A susceptance-cancellation methodology with rigorous equations are obtained in [23] to design input-port reflectionless lowpass filters of arbitrary odd order and stopband attenuation. Reflectionless filter prototype and its distributed implementation are presented in [24] with only input-port quasi-reflectionless in a limited frequency range.…”

Section: Introductionmentioning

confidence: 99%

Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-band Rejection

Wu¹,

Li²,

Liu³

2020

Preprint

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High-order quasi-reflectionless bandpass filters with improved passband flatness and good impedance matching both in-band and out-of-band are proposed in this work. The proposed design consists of conventional coupled-lines bandpass sections loaded with the presented absorptive stubs at the input and output. Analysis shows that the absorptive stub is equivalent to a 2-pole bandstop filter. Compared to the prior art, the higher-order nature of the presented absorptive stub enables a flatter passband and better out-of-band rejection. The overall filter stopband attenuation can be readily improved by increasing the number of coupled-lines sections without altering the passband responses. Furthermore, cross-coupling between the two absorptive stubs can be used to improve the out-of-band rejection by introducing two transmission zeros without affecting the absorption characteristics. The proposed design concepts are experimentally validated by the design and fabrication of a set of 2.4-GHz 1-, 2-, and 3-pole microstrip quasi-reflectionless bandpass filters. Measured frequency responses of these filters closely match those of the simulation.

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“…Frequency selective surfaces were designed to utilize the inherent loss of unit cells to absorb energy [30]. Reflectionless filters are becoming mature in recent circuit research, where resonators are usually loaded with resistors [31][32][33][34] to absorb backward waves. Without complex loaded networks, recent works also utilize the loss in dielectrics and metals to suppress backward reflections [35,36].…”

Section: Introductionmentioning

confidence: 99%

Rainbow Trapping with Long Oscillation Lifetimes in Gradient Magnetoinductive Metasurfaces

Shi

Davis

et al. 2019

Phys. Rev. Applied

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We report a gradient metasurface design at microwave bands as an elegant approach to realize the goal of "rainbow trapping" for the storage of waves involving wave localization and absorption phenomena. A longitudinally placed coplanar waveguide is loaded with gradient metasurfaces on both sides, where split-ring resonators (SRRs) are the basic cell. The same SRRs are arranged along the transverse direction to establish magnetoinductive channels. Waves of different frequencies are coupled to corresponding SRRs at different positions in metasurfaces. Resonant trapping with a long oscillation life time enhances the absorption caused by inherent losses of the materials, thereby suppressing reflections. Both simulations and measurements verify the existence of "rainbow trapping." The proposed strategy enhances the interaction between waves and matter, opening an avenue for further component designs, including absorptive filters, multiplexers, and buffers.

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Twofold Reflectionless Filters of Inverse-Chebyshev Response With Arbitrary Attenuation

Cited by 48 publications

References 6 publications

High-Order Dual-Port Quasi-Absorptive Microstrip Coupled-Line Bandpass Filters

High-Order Dual-Port Quasi-Absorptive Microstrip Coupled-Line Bandpass Filters

Quasi-Reflectionless Microstrip Bandpass Filters With Improved Passband Flatness and Out-of-band Rejection

Rainbow Trapping with Long Oscillation Lifetimes in Gradient Magnetoinductive Metasurfaces

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