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Reconfigurable ring filter with controllable frequency response.

Ab Wahab N, Mohd Salleh MK, Ismail Khan Z, Abd Rashid NE - ScientificWorldJournal (2014)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Microwave Technology Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40150 Shah Alam, Selangor, Malaysia.

ABSTRACT
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.

Show MeSH
Reconfigurable ring filter electrical length, lr, and four shunted capacitors, designed at center frequency fo = 2 GHz for Zr = 85 Ω, Zoe = 70 Ω, Zoo = 35 Ω, and Cr = 1 pF. (a) Topology and (b) frequency responses.
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fig1: Reconfigurable ring filter electrical length, lr, and four shunted capacitors, designed at center frequency fo = 2 GHz for Zr = 85 Ω, Zoe = 70 Ω, Zoo = 35 Ω, and Cr = 1 pF. (a) Topology and (b) frequency responses.

Mentions: A ring resonator is shunted with four capacitive elements, Cr, at the edges of the ring lines to vary the nominal electrical length, lr, of the ring. The variation of electrical length depends on the variation values of Cr to reconfigure the nominal center frequency to a new position. As shown in Figure 1(a), the ring is reconfigured with a set of chosen impedances as follows: ring impedance, Zr = 85 Ω, even-mode impedance, Zoe = 70 Ω, and odd-mode impedance, Zoo = 35 Ω, while the tuning element known as reconfigured capacitor, Cr, is chosen to be equal to 1 pF. Figure 1(b) illustrates the frequency responses between the reconfigured ring and the nominal ring without the four reactive elements. As observed, the nominal center frequency, fo, is reconfigured to the left at fo-x due to the changes in electrical length of the ring lines.


Reconfigurable ring filter with controllable frequency response.

Ab Wahab N, Mohd Salleh MK, Ismail Khan Z, Abd Rashid NE - ScientificWorldJournal (2014)

Reconfigurable ring filter electrical length, lr, and four shunted capacitors, designed at center frequency fo = 2 GHz for Zr = 85 Ω, Zoe = 70 Ω, Zoo = 35 Ω, and Cr = 1 pF. (a) Topology and (b) frequency responses.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4121041&req=5

fig1: Reconfigurable ring filter electrical length, lr, and four shunted capacitors, designed at center frequency fo = 2 GHz for Zr = 85 Ω, Zoe = 70 Ω, Zoo = 35 Ω, and Cr = 1 pF. (a) Topology and (b) frequency responses.
Mentions: A ring resonator is shunted with four capacitive elements, Cr, at the edges of the ring lines to vary the nominal electrical length, lr, of the ring. The variation of electrical length depends on the variation values of Cr to reconfigure the nominal center frequency to a new position. As shown in Figure 1(a), the ring is reconfigured with a set of chosen impedances as follows: ring impedance, Zr = 85 Ω, even-mode impedance, Zoe = 70 Ω, and odd-mode impedance, Zoo = 35 Ω, while the tuning element known as reconfigured capacitor, Cr, is chosen to be equal to 1 pF. Figure 1(b) illustrates the frequency responses between the reconfigured ring and the nominal ring without the four reactive elements. As observed, the nominal center frequency, fo, is reconfigured to the left at fo-x due to the changes in electrical length of the ring lines.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Microwave Technology Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40150 Shah Alam, Selangor, Malaysia.

ABSTRACT
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.

Show MeSH