New Bandstop Filter Circuit Topology and Its Application to Design of a Bandstop-to-Bandpass Switchable Filter

Lee, Juseop; Naglich, Eric J.; Sigmarsson, Hjalti H.; Peroulis, Dimitrios; Chappell, William J.

doi:10.1109/tmtt.2012.2237036

Cited by 60 publications

(22 citation statements)

References 16 publications

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“…The coupling matrix method is widely used to design narrow band filters with different functionalities such as tunable center frequency (f 0 ) and bandwidth, switchable filter from bandstop to all-pass filter, and bandstop to bandpass switchable filter [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

Chaudhary¹,

Jeong²

2016

PIER

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Abstract-This paper presents a comprehensive method to analyze negative group delay (NGD) phenomenon at microwave frequency. This method is based on a coupling matrix with finite unloaded quality factor resonators. Unlike conventional NGD circuit topologies that use a lumped resistor R along with bandstop resonators, the proposed topology does not require any R for generating NGD and therefore, provides fully distributed circuit realization. The proposed topology has both source to load and inter-resonator coupling structures. Analytical design equations are provided to obtain predefined NGD with matched input/output ports; the proposed structure therefore does not require any extra matching networks. From analytical analysis, it is also found that the NGD bandwidth as well as magnitude flatness can be controlled by inter-resonator couplings. The proposed design theory is proven through fabrications of NGD circuit at a center frequency of 2.14 GHz. The measurement results are in good agreement with simulations and predicted theoretical results.

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Section: Introductionmentioning

confidence: 99%

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

Chaudhary¹,

Jeong²

2016

PIER

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“…Therefore, 4-pole bandstop filters based on Fig. 1(a) result in more compact size compared to a 4-pole filter using two 270 transmission lines and one 90 transmission line [15], and to a 4-pole filter using two 90 transmission lines [16]. Reexamining Fig.…”

Section: A Coupling Structuresmentioning

confidence: 99%

“…Under the condition of the same coupling coefficients, the 2-pole bandstop filter results in a bandwidth of 3.1%. The 2and 4-pole bandpass filters also result in a bandwidth of 5.4% and 4.5%, respectively [15]. Note that this reconfigurable filter topology does not allow for independent bandwidth design for each filter mode, except for the 4-pole bandpass filter.…”

Section: A Tunable Filter Designmentioning

confidence: 99%

“…For a high interference environment, the bandpass-to-bandstop filters operate in the bandstop filter mode to reduce the high power interferer close to the desired signal, while the bandpass filter mode is selected for a lower interference environment [14]. Tunable bandpass-tobandstop filters with a 2-or 4-pole response are presented based on a coupling diagram with a source/load coupling control in [14] and [15]. The tunable filter in [16] also shows a bandpass-to-bandstop transformation as well as bandwidth control.…”

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confidence: 99%

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0.7–1.0-GHz Reconfigurable Bandpass-to-Bandstop Filter With Selectable 2- and 4-Pole Responses

Cho

Rebeiz

2014

IEEE Trans. Microwave Theory Techn.

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A 0.7-1.0-GHz reconfigurable bandpass-to-bandstop filter with selectable 2-and 4-pole responses is presented. The proposed filter can act as a 2-or 4-pole bandpass or bandstop filter by changing the coupling paths using zero-value coupling coefficients. The 4-pole bandpass filter mode also includes bandwidth control. The filter is built on a Duroid substrate with and mil. The center frequency tuning, as well as the bandpass-to-bandstop transformation and the selection of the number of poles are achieved using silicon varactor diodes and RF microelectromechanical systems switches. In the 2-and 4-pole bandpass modes, an insertion loss of 4.9-2.9 and 6.1-4.8 dB is measured at 0.71-0.99 and 0.72-1.01 GHz, respectively. The 4-pole bandpass mode also shows a bandwidth tuning of 28-85 MHz at 0.9 GHz. In the 2-and 4-pole bandstop modes, rejection levels of 24-28 and 32-41 dB are measured at 0.64-0.96 and 0.71-0.96 GHz, respectively. The application areas are in reconfigurable filters for wideband radios under high interference environments.Index Terms-Bandpass filter, bandstop filter, bandwidth control, reconfigurable-pole filter, tunable filter.

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“…Hence, studies have also been expanded to explore multifunction filter. In [5,6], it is shown that reconfigurable filters can have two functionalities by utilizing a number of switches, but having multiple switches in filter structures is one of drawbacks sacrificing insertion loss performance.…”

Section: Introductionmentioning

confidence: 99%

Frequency-tunable bandstop-bandpass dual-function microwave filter

Lee¹,

Lee²,

Park

et al. 2015

IEICE Electron. Express

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This letter presents a frequency-tunable, dual-function, microwave filter with both bandpass and bandstop functionalities. The filter uses a single switch to change the functionality minimizing the insertion loss, and it can replace a traditional filter bank structure that contains two filters and two switches. Frequency-tunable substrate-integrated waveguide (SIW) resonators are adopted in this filter design. Measured results show that both bandpass and bandstop responses can be tuned from 3.0 GHz to 3.6 GHz. The measured minimum insertion loss at the center frequency is 1.1 dB for the bandpass mode and the attenuation at the center frequency is greater than 40 dB over the entire frequency tuning range.

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New Bandstop Filter Circuit Topology and Its Application to Design of a Bandstop-to-Bandpass Switchable Filter

Cited by 60 publications

References 16 publications

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

Negative Group Delay Phenomenon Analysis Using Finite Unloaded Quality Factor Resonators

0.7–1.0-GHz Reconfigurable Bandpass-to-Bandstop Filter With Selectable 2- and 4-Pole Responses

Frequency-tunable bandstop-bandpass dual-function microwave filter

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