Practical design of variable fractional-order capacitors with a single tuning feature using field effect transistors and variable capacitance diodes

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26220%2F26%3A0198331" target="_blank" >RIV/00216305:26220/26:0198331 - isvavai.cz</a>

Alternative codes found

RIV/60162694:G43__/26:00564723

Result on the web

<a href="https://www.nature.com/articles/s41598-025-07319-5" target="_blank" >https://www.nature.com/articles/s41598-025-07319-5</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1038/s41598-025-07319-5" target="_blank" >10.1038/s41598-025-07319-5</a>

Result language

angličtina

Original language name

Practical design of variable fractional-order capacitors with a single tuning feature using field effect transistors and variable capacitance diodes

Original language description

This paper presents two discrete circuit solutions for realizing passive, electronically adjustable constant-phase elements, specifically half-order capacitors with a -45 degrees phase shift. Fractional-order capacitors with electronically adjustable pseudocapacitance are especially useful for designing tunable filters and oscillators. The ability to adjust pseudocapacitance electronically and continuously is a major improvement over traditional passive solutions. Their pseudocapacitance can be controlled by a DC voltage, allowing key parameters like the cut-off or oscillation frequency to be tuned. Two presented design approaches differ in accuracy, tuning range, and signal-handling capability. Both solutions maintain a constant phase over one frequency decade, with a phase ripple within +/- 2 degrees. The tuning range spans from hundreds of Hz to several MHz. Presented solutions allow pseudocapacitance tuning in range of hundreds of nano F/sec0.5 (with varicaps) and tens of micro F/sec0.5 (with MOSFETs). The MOS-based circuit offers a tuning ratio of 7 but shows a 19% deviation between simulation and measurement. It also suffers from notable nonlinearity, with undistorted operation limited to signal levels up to 20 mV peak-to-peak. The varicap-based solution achieves a tuning ratio of 5, with high accuracy (up to 6% error), and handles input signals in the hundreds of mV with acceptable distortion. PSpice simulations and laboratory measurements confirm the performance of both designs.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

21100 - Other engineering and technologies

Project

<a href="/en/project/GA23-06070S" target="_blank" >GA23-06070S: Fundamental research on designing of CMOS fractional-order elements</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Scientific Reports

ISSN

2045-2322

e-ISSN

—

Volume of the periodical

15

Issue of the periodical within the volume

7

Country of publishing house

GB - UNITED KINGDOM

Number of pages

17

Pages from-to

1-17

UT code for WoS article

001522990200021

EID of the result in the Scopus database

2-s2.0-105009551424