Design Of Reconfigurable Filter Research Articles

Improving Generalized Discrete Fourier Transform (GDFT) Filter Banks with Low-Complexity and Reconfigurable Hybrid Algorithm

With ever-increasing wireless network demands, low-complexity reconfigurable filter design is expected to continue to require research attention. Extracting and reconfiguring channels of choice from multi-standard receivers using a generalized discrete Fourier transform filter bank (GDFT-FB) is computationally intensive. In this work, a lower compexity algorithm is written for this transform. The design employs two different approaches: hybridization of the generalized discrete Fourier transform filter bank with frequency response masking and coefficient decimation method 1; and the improvement and implementation of the hybrid generalized discrete Fourier transform using a parallel distributed arithmetic-based residual number system (PDA-RNS) filter. The design is evaluated using MATLAB 2020a. Synthesis of area, resource utilization, delay, and power consumption was done on a Quartus 11 Altera 90 using the very high-speed integrated circuits (VHSIC) hardware description language. During MATLAB simulations, the proposed HGDFT algorithm attained a 66% reduction, in terms of number of multipliers, compared with existing algorithms. From co-simulation on the Quartus 11 Altera 90, optimization of the filter with PDA-RNS resulted in a 77% reduction in the number of occupied lookup table (LUT) slices, an 83% reduction in power consumption, and an 11% reduction in execution time, when compared with existing methods.

Reconfigurable Filtering of Neuro-Spike Communications Using Synthetically Engineered Logic Circuits.

High-frequency firing activity can be induced either naturally in a healthy brain as a result of the processing of sensory stimuli or as an uncontrolled synchronous activity characterizing epileptic seizures. As part of this work, we investigate how logic circuits that are engineered in neurons can be used to design spike filters, attenuating high-frequency activity in a neuronal network that can be used to minimize the effects of neurodegenerative disorders such as epilepsy. We propose a reconfigurable filter design built from small neuronal networks that behave as digital logic circuits. We developed a mathematical framework to obtain a transfer function derived from a linearization process of the Hodgkin-Huxley model. Our results suggest that individual gates working as the output of the logic circuits can be used as a reconfigurable filtering technique. Also, as part of the analysis, the analytical model showed similar levels of attenuation in the frequency domain when compared to computational simulations by fine-tuning the synaptic weight. The proposed approach can potentially lead to precise and tunable treatments for neurological conditions that are inspired by communication theory.

A broadband reconfigurable bandpass filter based on half-mode substrate integrated waveguide and spoof surface plasmon polarization structure

In this paper, a design method of reconfigurable broadband bandpass filter, with the advantage of adjustable bandwidth, is proposed by fabricating a hybrid sharing waveguide which is consist of half mode substrate integrated waveguide (HMSIW) and spoof surface plasmon polarization (SSPP). By adding a U-shaped resonant unit and a container structure to the bandpass filter, then through the movement of the slide on U-shaped groove and the alteration of the medium parameters in the container, the lower cut-off frequency of HMSIW and upper cut-off frequency of SSPP can be independently controlled by the fine tuning of the structures easily without changing the filter parameters. A prototype sample is fabricated to demonstrate and confirm the validity of the proposed method. The measured largest passband ranges from 11.5 to 14.5 GHz with the relative bandwidth of 23% which can be adjusted within a certain scope. The design of reconfigurable filter is realizing by the combination of HMSIW–SSPP structure and the concept of tunable filter. The proposed method can be used to develop different broadband bandpass filters.

Design of reconfigurable low-complexity digital hearing aid using Farrow structure based variable bandwidth filters

A low complexity digital hearing aid is designed using a set of subband filters, for various audiograms. It is important for the device to be made of simple hardware, so that the device becomes less bulky. Hence, a low complexity design of reconfigurable filter is proposed in this paper. The tunable filter structure is designed using Farrow based variable bandwidth filter. The coefficients of the filter are expressed in canonic signed digit format. The performance can be enhanced using optimization algorithm. Here, we have explored the strength of hybrid evolutionary algorithms and compared their various combinations to select a proper coefficient representation for the Farrow based filter, which results in low complexity implementation.

High-Tunability and High-<formula formulatype="inline"><tex Notation="TeX">$Q$</tex></formula>-Factor Integrated Ferroelectric Circuits up to Millimeter Waves

Based on advanced industrial fabrication processes and on specialized design strategies, a new class of ferroelectric metal-insulator-metal (MIM) capacitors with high tunability and high quality factor ( Q-factor) is here presented. Modeled by means of lumped element equivalent circuits and experimentally validated up to 67 GHz, a maximum tunability of 81% (0-20-V bias), and a Q-factor improvement up to 30% (at 0 V) could be demonstrated at 1 GHz. These varactors have been exploited in the design of reconfigurable filters, with a center frequency at around 1 GHz that can be tuned up to 112%, and a figure of merit (FoM) per applied bias better than 31.5 dB <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> /kV. Owing to their promising features, these materials have been exploited to design small-size capacitors suitable for millimeter-wave frequencies. The results demonstrate tunabilities and FoMs superior to the state-of-the-art. Based on this, two 60-GHz tunable phase shifters are proposed. They represent the first example of such devices based on MIM (Ba,Sr)TiO3 (BST) capacitors. In terms of insertion loss, size, FoM, and FoM per bias they show a remarkable improvement with respect to the state-of-the-art of ferroelectric-based devices, thus proving that the BST represents a promising candidate to operate into the millimeter frequency band.

Reconfigurable ring filter with controllable frequency response.

Reconfigurable ring filter based on single-side-access ring topology is presented. Using capacitive tuning elements, the electrical length of the ring can be manipulated to shift the nominal center frequency to a desired position. A synthesis is developed to determine the values of the capacitive elements. To show the advantage of the synthesis, it is applied to the reconfigurable filter design using RF lumped capacitors. The concept is further explored by introducing varactor-diodes to continuously tune the center frequency of the ring filter. For demonstration, two prototypes of reconfigurable ring filters are realized using microstrip technology, simulated, and measured to validate the proposed concept. The reconfigured filter using lumped elements is successfully reconfigured from 2 GHz to 984.4 MHz and miniaturized by 71% compared to the filter directly designed at the same reconfigured frequency, while, for the filter using varactor-diodes, the frequency is chosen from 1.10 GHz to 1.38 GHz spreading over 280 MHz frequency range. Both designs are found to be compact with acceptable insertion loss and high selectivity.