Tunable Multiband Balanced Bandstop Filter With High CMRR

Borah, Dubari; Kalkur, T. S.

doi:10.2528/pierc19041607

Cited by 4 publications

(4 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The design process starts with the extraction of DM equivalent circuit. At any tuning state, the DM multiband frequency transformation associated with this topology is given by [12],…”

Section: Design Examplementioning

confidence: 99%

“…In [11], a multiband differential BSF is presented, but it is not tunable. The multiband balanced BSF design in [12] is reconfigurable, but its size is significantly large for UHF band applications, and the realizable fractional bandwidth is limited due to the use of distributed elements. Another shortcoming associated with both the designs in [11] and [12] is that they require open stubs along the symmetry plane to achieve high CMRR.…”

Section: Introductionmentioning

confidence: 99%

“…This paper introduces a differential reconfigurable multiband BSF with all lumped elements for the first time based on the microstrip differential BSF design reported in [12]. The design is symmetrical about the horizontal central plane.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ultra-Compact Balanced Multiband Fully Reconfigurable Bandstop Filter

Borah¹,

Kalkur²

2020

PIER C

Self Cite

View full text Add to dashboard Cite

This paper introduces a balanced (differential) multiband reconfigurable (tunable) bandstop filter (BSF) using all lumped elements. The main features of the design include its ultra-compact size as well as flexibility to control any frequency band independently in terms of both center frequency and absolute bandwidth (ABW). In the proposed structure, the corresponding non-resonating nodes (NRN) of the symmetrical bisections are connected to N number of LC π-circuits (N-band cell) through capacitors. Again, in each symmetrical bisection, K number of NRNs are series cascaded through LC π-circuits. This results in a Kth order N-band stopband (notch) response in differential mode (DM) operation whereas provides a passband response when excited by a common mode (CM) signal. Reconfiguration of any DM stopband is obtained by using tunable capacitors for the corresponding LC π-circuit in each N-band cell and also, for its coupling capacitors to the NRNs. To validate the proposed topology, a dualband differential tunable BSF is designed and fabricated where both DM stopbands are controlled independently in the range of 1.16 GHz-1.32 GHz. Also, the bandwidth of each band is varied independently by 20-50 MHz without affecting the other band. At any tuning state, DM stopband rejection for each band is found to be ≥ 19 dB, resulting in a minimum CMRR value of 19 dB. The fabricated prototype occupies an area of 0.13λ g × 0.04λ g (21 mm × 7 mm) where λ g is the guided wavelength at the center frequency of the entire spectral range, and the experimental results show a good agreement with the simulation results.

show abstract

“…The design process starts with the extraction of DM equivalent circuit. At any tuning state, the DM multiband frequency transformation associated with this topology is given by [12],…”

Section: Design Examplementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultra-Compact Balanced Multiband Fully Reconfigurable Bandstop Filter

Borah¹,

Kalkur²

2020

PIER C

Self Cite

View full text Add to dashboard Cite

show abstract

“…To achieve better noise immunity, the balanced structures of these filters are preferred to their single-ended counterparts [6][7][8][9]. Some of the novel multiband balanced band stop filter (BSF) structures with different features have been discussed in [1,[10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Temperature Effect on a Lumped Element Balanced Dual-Band Band-Stop Filter

Borah¹,

Kalkur²

2020

PIER M

Self Cite

View full text Add to dashboard Cite

In this manuscript, the thermal effect on a lumped element balanced (differential) dualband band-stop filter (BSF) has been discussed in detail for the first time. The response of a novel filter should maintain consistency over a wide range of temperature. Although any microwave filter in general is designed for room temperature condition, the filter is employed for applications where the operating temperature constantly changes. Therefore, it is necessary to check the reliability of the filter response within a specific temperature range based on its application. Modern simulation software helps to make an initial assumption about the filter performance at different thermal conditions before its lab testing or actual application. Here, a quantitative analysis has been provided to show how change in temperature contributes to the change in each component value of a lumped element filter. This analysis is followed by a simulation to show that a balanced lumped element filter exhibits lower loss than its single-ended counterpart. Also, as the temperature varies, the balanced design demonstrates less deviation in the loss value than a two-port design. Next, a balanced dual-band BSF prototype with center frequencies 1.151 GHz and 1.366 GHz (25 • C) is characterized with a 4-port network analyzer under different temperature conditions. The experimental results exhibit a good match with the simulation results. For a variation of 80 • C in temperature, the maximum deviation obtained for the filter center frequency, absolute bandwidth (ABW), and insertion loss (Sdd21) are 5 MHz, 2.8 MHz and 2 dB, respectively.

show abstract