Dual Bandstop Filter Research Articles

An ultrawideband antenna with two independently tunable notch bands

This paper presents a planar CPW-fed Ultrawideband (UWB) antenna with two independently tunable notch bands. The proposed design consists of a modified Rhombus-shaped monopole structure that is integrated with a dual band-stop filter based on hexagonal split ring resonators (HSRR). The antenna is capable of suppressing multiple frequency bands within ultrawideband range (3.1–11 GHz) such as WLAN and X-band downlink satellite communication frequency bands with an independent tunable mechanism to fulfill the on-demand band rejection. The frequency reconfigurability of the two notch bands is obtained by loading the hexagonal filter arms with two varactor diodes (for each band). Details of antenna design steps and reconfigurability mechanism are illustrated. The notch band element is explained using equivalent circuit model and surface current distribution at lower and higher notch frequency bands. A prototype of the proposed design is printed on the RO4003C (ϵr = 3.55) substrate printed circuit board (PCB) and tested to authenticate the performance. The proposed antenna volume is 21.5 ▪ 48 ▪ 1.524 mm3 and demonstrates an omnidirectional radiation pattern in E and H planes with an average gain of 3.7 dBi across the operational passbands, while a sharp reduction in gain of -6.8 dBi and -3.5 dBi is achieved at the lower and higher notch bands, respectively. Continuous tuning is achieved experimentally from 5.08 to 5.77 GHz and 7.75 to 8.52 GHz for the lower and higher notch bands, respectively. Excellent agreement is observed between the simulated and measured results. Application areas include radio-frequency identifications, ground-penetrating radar, and wireless communications.

Compact Dual Bandstop Filter Using Folded Lines and Genetic Algorithm

A novel method for creating a dual band bandstop filter with a meandering architecture is presented. Proposed bandstop filter shows two notch bands, one at 5.6 to 7.2 GHz and the other at 8 to 11 GHz. The designed filters simulated on HFSS software and fabricated on FR-4 substrates, filter dimensions have been optimized using GA. Filter shows S11 of 1dB and S21 of -18 dB at notch frequency 6.4 GHz and S11 of 1.2dB and S21 of -38 dB at notch frequency 9 GHz. The suggested filter has two pass bands one is up to 5 GHz for wireless communication and another is from 7.4 to 7.9 GHz for C band applications.

Dual band stop filter design via frequency transformation and synthesis with lumped resonators

This study presents a new compact design technique for dual band stop (DBS) filter. Analytical formulation of DBS frequency transformation/mapping is derived in terms of parametric representation of band characteristic of DBS filter. The analytical derivation of the transformation function is based on sequential application of classical low pass to band stop (LP to BS) and low pass to band pass (LP to BP) transformations. Assigned band characteristic of DBS filter can be achieved by applying the proposed transformation function on an LP prototype network. The explicit network topologies for DBS reactance mapping are presented. Several numerical examples are provided to validate the proposed mapping function. An implantation example of DBS filter for GSM900 and GSM1800/UMTS bands is given. Mixed element realisation of the designed filter and measurement results of the design are presented.

Effect of rotational split ring resonator on dual bandstop filter

This paper presents analysis and design of a compact dual bandstop filter using an array of square split ring resonators (SSRR). The SSRR are placed in the ground to cut off the unwanted signals. The results show that the angular orientation of the inner ring offers the possibility of designing dual bandstop filter with a small size and simple structure.

Synthesis Design of Microstrip Triple-Passband Dual-Stopband Filter Based on $\lambda /4$ Uniform-Impedance Resonators

A triple-passband, dual-stopband filter based on $\lambda /4$ uniform-impedance resonators (UIRs) is proposed in this letter. The triple-passband and dual-stopband frequency response is obtained by placing four transmission zeros inside a virtual wide passband. Presented with the equivalent circuit of the proposed filter, the analytical formulas of the structure for initial design are derived according to the synthesized coupling matrix without time-consuming tuning and optimization. Meanwhile, the low-insertion losses are achieved by the direct line connection of all resonators. Moreover, the fabricated filter features good return loss, wide bandwidth, and operating single frequency.

Open and short U-shaped microstrip resonators for second-order single- or dual-bandstop filter design

Open and short U-shaped microstrip resonators for second-order single- or dual-bandstop filter design

Novel Tunable Bandstop Resonators in SIW Technology and Their Application to a Dual-Bandstop Filter with One Tunable Stopband

Two novel tunable bandstop resonators in substrate integrated waveguide (SIW) technology are presented: a ridged SIW resonator and an open-ended coplanar waveguide (CPW) resonator that is etched into the SIW’s top metallization. The ridged SIW resonator shows a tuning range of 200 MHz at 5.54 GHz. The CPW resonator has a tuning range of 600 MHz at 3.8 GHz. The two bandstop resonators are combined to design a dual-band bandstop filter with one tunable stopband. Measured results confirm that the tunable bandstop circuits presented in this letter can be effectively used in reconfigurable SIW systems.

A compact dual stopband bandstop filter using defected SIR and Hilbert shape fractal structure

In this paper, a novel technique is proposed to design a dual band bandstop filter which is implemented with two defected stepped impedance resonators (SIRs) embedded on the input output transmission line. The embedded SIRs create a transmission zero at 2.5 GHz that generates the first stopband of the proposed filter. Introducing two Hilbert shaped fractal structure on the ground plane, the second stop band is employed at 3.5 GHz. The overall layout of the filter is realized with a size of 20 × 5 mm2. The proposed prototype is EM simulated and measured. The measured −10 dB bandwidth for first stopband is 0.1 GHz and for second stopband it is 0.14 GHz. The measured S-parameters exhibit an excellent out off band response with insertion loss less than 1.5 dB. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1345–1347, 2016

Reconfigurable Dual-Stopband Filters With Reduced Number of Couplings Between a Transmission Line and Resonators

This letter proposes a new design method for a bandstop filter with two stopbands. Contrary to a conventional method, the presented method allows for achieving two stopbands without increasing the number of the couplings between resonators and the transmission line connecting the input and output ports. In addition, a filter designed using the presented method can not only have different center frequencies but also have different bandwidths by adjusting the resonant frequencies of the resonators. For verification of the proposed approach a dual-stopband filter using four tunable substrate-integrated waveguide resonators has been designed and measured.

Substrate Integrated Waveguide Triple-Passband Dual-Stopband Filter Using Six Cascaded Singlets

A triple-passband, dual-stopband filter consisting of six cascaded singlets is introduced in substrate integrated waveguide (SIW) technology. Each singlet produces one independent transmission zero (TZ). Four of six TZs are placed within the filter passband, producing three passbands separated by two stopbands. The corresponding coupling matrix is synthesized based on a combination of well-known analytic and optimization methods. The SIW filter is designed for stopbands centered at 10.25 and 11.23 GHz, and passbands at 9.72, 10.76, and 11.76 GHz. The prototype is fabricated and measured. Good agreement between simulated and measured results is achieved.

A Plasmonic Triple-Wavelength Demultiplexing Structure Based on a MIM Waveguide With Side-Coupled Nanodisk Cavities

We propose and numerically investigate a plasmonic triple-wavelength demultiplexing structure based on metal-insulator-metal waveguides with side-coupled nanodisk cavities. The structure consists of three output channels, each of which is sandwiched by two nanodisk cavities and functions as a dual stop-band filter. The operation principle and transmission characteristics are analyzed by using the temporal coupled-mode theory and the finite-difference time-domain method. Simulation results show that the demultiplexed wavelength of each channel can be effectively tuned by adjusting the geometrical parameters of the structure. The proposed structure will find potential applications in photonic-integrated circuits and ultracompact optical communication systems.

Design of a Dual Stop-Band Filter Based on Coplanar Waveguide

This letter presents a dual stop-band filer based on coplanar waveguide (CPW), which consists of two spiral-shaped defected ground structure (DGS). The model of the equivalent circuit, discussing the influence of the spiral shape size, and simulated performances are presented. Finally, a dual stop-band filter is presented and verified by simulations, which is operated from 11.5 to 14 GHz and 23 to 28 GHz.

Novel Dual Band-Reject Microwave Filter Using C-Shaped Defected Ground Structures

In this paper, a new compact dual band-reject C-shaped defected ground structure (DGS) for microstrip line is introduced. Using two units of the same shaped DGS with different dimensions, a dual band-stop filter is designed and implemented. Results show that there are two parallel resonance frequencies at 2.468 GHz and 6.629 GHz with a very high Q-factor. The frequency characteristics of the proposed filter could be controlled by adjusting the DGS parameters such as width and length of both C-shaped patterns. Also, the distance between the two DGS structure could be adjusted for the required frequency characteristics. The proposed DGS provides Q-factor of more than 50 with attenuation of at least 20 dB at the resonant frequencies. The new introduced DGS filter is successfully designed and fabricated and the measured results are in a very good agreement with those obtained by numerical investigation.

A novel CSRR‐based defected ground structure with dual‐bandgap characteristics

AbstractA new type of dumbbell‐shaped defected ground structure (DGS) is introduced in this article. Its dual‐bandgap characteristics are reported for the first time and can be adjusted by changing the dimension of complementary split‐ring resonators (CSRR) unit and gap. The dual bandstop filter using proposed DGS is designed and fabricated. Measured results show that there are two bandgaps centered at 3.35 GHz and 5.82 GHz, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2908–2910, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24776

Metamaterial 전송선을 이용한 이중 대역 저지 필터

본 논문에서는 Metamaterial 전송선을 이용한 이중 대역 저지 필터를 제안하고 제작, 측정하였다. 이는 Wilkinson Power Divider의 형태를 바탕으로, 입력 단자에 신호를 인가하면 동일한 크기와 위상을 갖는 신호로 나눠진다. 이를 각각의 전송선에서 CRLH(Composite Right/Left-Handed) 구조와 D-CRLH(Dual Composite Right/Left-Handed) 구조를 이용하여 위상 변화를 유도한다. 본 논문에서는 TDMB 주파수 대역인 195 MHz와 DVB-T/H 주파수 대역인 670 MHz 대역에 대해 저지 대역 특성을 유도하였다. 이를 통해 제작한 필터의 크기는 <TEX>$30{\times}15\;mm$</TEX> 이며, -10 dB를 기준으로 대역폭을 측정한 결과 각각의 주파수 대역에서 73 %, 50 %의 결과를 얻을 수 있었다. This raper proposes a dual-bandstop filter, which is based on a metamaterial transmission line using the composite right/left-handed (CRLH) and dual composite right/left-handed (D-CRLH) structures. The metamaterial structure is used for miniaturization and dual-bandstop operation at the TDMB frequency range (195 MHz) and DVB-T/H frequency range (670 MHz). The size of the proposed filter is <TEX>$30{\times}15\;mm$</TEX>, and the -10 dB bandstop fractional bandwidth is approximately 73 % and 50 % at each frequency, respectively.

Dual bandstop resonator using combined split ring resonator and defected ground structure

AbstractDefected ground structure and split ring resonator are combined to form a compact dual bandstop filter or a dual pole bandstop filter. An equivalent circuit model is developed for the proposed structure and it agrees very well with EM simulation. A dual bandstop resonator was fabricated. Measurements and theoretical predictions are in a very good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1249–1253, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22464

Compact hybrid defected ground plane

AbstractA novel hybrid defected ground structure (DGS), which interleaves a photonic bandgap structure (PBGS), is investigated theoretically as well as experimentally. It yields distinct multiple passbands and stopbands. The novel structure can be used either a compact diplexer or a dual stopband filter. With Chebyshev distributions on the interleaved PBGS, the passband and stopband performances improve significantly. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 266–270, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20607