Compact Ultra-wideband Filter Research Articles

Design of a Compact UWB Filter with Low Insertion Loss and High Selectivity

The design procedure of a novel compact ultra-wideband (UWB) filter with high selectivity and low insertion loss is presented in this paper. The proposed filter consists of a simple planar combline filter at the top of a substrate and a non-intuitive shape of the defected ground structure (DGS) on the other side. The UWB filter is obtained by optimizing the shape of DGS and the combline parameters with a mixed integer genetic algorithm. The mixed integer genetic algorithm optimizes both continuous and binary values simultaneously. The continuous values define the combline parameters while the binary values define the shape of DGS. The detail of the design procedure is presented and validated by fabricating a prototype of the proposed filter. The measured insertion loss of the proposed filter in the mid-band frequency is less than 0.5 dB. The measurement results also show that the proposed UWB filter with a very compact structure has five transmission zeroes at the upper and lower stop bands.

Compact ultrawideband filter with reconfigurable band notch characteristics

ABSTRACT A novel compact ultrawideband (UWB) filter with reconfigurable band notch property is presented. Stepped impedance slotline (SISL) resonator along with two open-ended coupled microstrip is used for the realisation of UWB filter. The WLAN band of rejection is obtained by placing the U-shaped DGS near the SISL resonator. Furthermore, two capacitors are placed in the active slot of U-shaped DGS to obtain WiMAX band of rejection. The proposed UWB filter with reconfigurable band notched characteristics is fabricated and measured. The measured results agree well with the simulated results.

Design of a Super Compact UWB Filter Based on Hybrid Technique with a Notch Band Using Open Circuited Stubs

This paper presents a new design of a super compact Ultra wideband (UWB) band-pass filter (BPF) with rejection of X-band satellite applications. For covering the UWB bandpass, the proposed filter is realized using hybrid technique which is achieved by using a Microstrip-Coplanar waveguide-Microstrip transition. The basic structure consists of a modified microstrip in the top layer and CPW in the bottom layer. Later, open-circuited stubs are embedded in the top to implement in-band transmission zeros (TZ) so as to circumvent interference. The simulated results show that the UWB bandpass filter has a high adaptation (S11 ≤ −18 dB) and insertion loss better than 0.4 dB at the passband. The impedance bandwidths are about 114% (3–11 GHz) with upper stopband extends to more than 14 GHz with a depth of greater than 38 dB. In addition, the UWB BPF shows a flat group delay performance with a variation of about 0.15 ns over the entire bandwidth. A prototype of the filter is fabricated and tested. Good agreement is achieved between measurement and simulation. The proposed UWB BPF is compact in size with overall dimensions of 14 by 9.2 mm2. Consequently, the obtained results prove that the presented filter is suitable for UWB wireless devices.

Multiple passband transmission zeros embedded compact UWB filter based on microstrip/CPW transition

This manuscript presents an ultra-wideband (UWB) bandpass filter (BPF) with dual transmission zeros (TZ) embedded in the passband for interference free operation in indoor environment. Based on the vertical electromagnetic (EM) coupling of microstrip-to-coplanar waveguide (CPW) transition, the structure has two similar microstrips placed adjacent on the top plane whereas a short-circuited CPW forms the ground. The response of this BPF is quasi-elliptical in nature with two TZs at either passband edges which enhances selectivity and improves insertion/return loss. To this basic BPF, novel sectoral folded split ring resonator (SFSRR) and spiral resonator (SR) are appended in the slots of the ground plane which produce dual TZs in the passband at 4.5 and 8 GHz respectively. A prototype of the proposed structure is fabricated and tested. The dual notched BPF is developed on a low cost substrate and is of compact size occupying an area of 21.2 × 16 mm2.

Design of Compact UWB Filter Using Parallel-coupled Line and Circular Open-circuited Stubs

This article encompasses the design of compact ultra-wideband (UWB) bandpass filter with low insertion loss and high selectivity using circular open-circuited stubs (COSs). Low insertion loss from two COSs and Multiple Mode Resonator (MMR) from three pairs of parallel-coupled lines are constituted to obtain the UWB band. The proposed filter has multiple resonant frequencies in the passband and two transmission zeros perceived at stop band/passband transition edges. It has a 3-dB fractional bandwidth of 110% and it covers the entire UWB band of 3.1–10.6 GHz. The measured passband insertion loss and group delay are 0.35 dB and 0.42 ns, respectively. Moreover, the presented filter is a single-layered structure since it is more comfortable to be integrated into a printed circuit board (PCB). The simulated and measured performance of the presented filter is in good agreement. The filter finds its application in low power handling single-layered PCBs, unlicensed short and medium distance communications.

A Compact UWB Bandpass Chip Filter on a GaAs Substrate with Modified Chebyshev Structure

Ultra-Wideband (UWB) systems are widely used in low-power, high-speed, high-security short-range wireless communication systems throughout digital homes and offices. In the RF front-end of a UWB system, bandpass filters (BPFs) are used to put through the passband signals and reject the stopband signals. Most UWB BPFs are designed with dielectric materials on circuit boards or LTCC technology. In this paper, a very compact fully integrated UWB chip filter is proposed and designed on a GaAs substrate with nitride as dielectric layers to meet the small size requirement of portable devices for next-generation UWB applications. The filter is constructed with a modified Chebyshev structure. The final filter circuit contains only four inductors instead of six for the conventional Chebyshev filter, which makes the chip more compact and cost effective. The filter is designed and fabricated on a 0.25 μm GaAs pHEMT technology with a chip size of only 0.73 mm × 0.51 mm including the chip edge and scribe line area, while the filter core area is only 0.61 mm × 0.39 mm, including bonding PADs. The measurement results illustrated that the proposed BPF shows a passband covering the frequency range of 3.1–9.0 GHz, the minimum passband insertion loss is only 1.5 dB, the stopband rejection is better than −30 dB throughout frequencies below 2 GHz and above 12 GHz, S11 is less than −16 dB, and S22 is better than −11 dB during the whole passband range. It demonstrated that the proposed filter can be considered as one of the most compact UWB filters.

Compact edge and end coupled wide band filter with notch at 5GHz

In this paper a compact Ultra Wide Band filter with notch at WLAN frequency is designed. The filter is a designed using coupled lines arranged in inter digital capacitor form. The filter is designed to allow microwave signals in the range of 2GHz to 7GHz with a notch at 5GHz. The measured results show the notch at 5GHz with transmission coefficient of -14dB. With uniform group delay in pass band and nonlinear group delay at notch frequency.

Compact UWB filter with narrow notched band based on grounded circular patch resonator

In this paper, a compact ultra-wideband (UWB) band-pass filter (BPF) with a single narrow notched band is proposed. This filter is designed using a novel multiple-mode resonator (MMR) based on a grounded circular patch resonator (GCPR). The proposed MMR generates three main resonances and two transmission zeros (TZs). A semi-lozenge slot (SLS) is proposed to control resonant frequencies and obtain UWB operation. The 3dB notched band is achieved from 5.65-5.8 GHz by connecting an arrowhead stub inside the filter. The UWB filter has been simulated, fabricated and measured. The dimension of the designed filter is about 0.31 × 0.31 λg × λg.

Ultra-Wideband Ridged Half-Mode Folded Substrate-Integrated Waveguide Filters

In this letter, compact ultra-wideband filters are designed by employing a novel ridged half-mode folded substrate-integrated waveguide (RHMFSIW) and double-ridged half-mode SIW (DRHMSIW). The RHMFSIW is proposed by loading the half-mode folded substrate integrated waveguide with a ridge, where the ridge introduces additional capacitance hence leading to a lower cutoff frequency and a smaller size. Compact ultra-wideband filters are designed and fabricated based on the RHMFSIW. Another novel DRHMSIW is developed to implement the tight coupling required in the ultra-wideband filters. To improve the out-of-band rejection while keeping a small size, mixed coupling is employed in the ultra-wideband filter to generate transmission zeros. The proposed filters demonstrate the advantage of high selectivity, low loss, compact size, and easy integration with other electronic systems.

Compact ultra wide band filter using triangular patch resonators

A compact ultra wide band pass filter has been proposed in this paper. The band pass operation of the filter has been obtained with the combinations of high pass filter and low pass filter. The low pass filter used in the combined structure is designed using the triangular patch resonators and the high pass filter is designed using shorted stubs. The three different topologies to combine the low pass and high pass filter are compared. The final structure gives a very compact configuration of ultra wide band pass filter. The design methodology of the proposed filter is elaborated. The designed structure is simulated and fabricated. The group delay of the filter gives almost flat for the entire operation band. A good agreement has been seen between simulated and measured values of scattering parameters. The fractional band width has been achieved as 130%.

Compact ultra-wideband filter with dual notched bands based on complementary split ring resonators

A compact ultra-wideband (UWB) bandpass filter (BPF) with double notched bands is presented in this article.The proposed BPF comprises one T-shaped multiple modes resonator and two microstrip-CPW transition structures etched with different complementary split ring resonators (CSRRs). A CSRR etched on the coupled surface is adopted to produce narrow stop band with high rejection level. Its notched response can be mainly controlled by tuning the length and width of the gap of the CSRR. The fabricated BPF achieved dual notched bands at 5.3 and 5.775 GHz with 10 dB rejection bandwidth of 4.5 and 2.6%, and rejection level of 21.49 and 17.35 dB, respectively. The proposed notched UWB BPF has the advantages of compact size, good selectivity, and flat group delay. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2509–2512, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25554

Compact ultra-wideband filter using coupled-line and short-ended stub

A compact ultra-wideband filter is presented. The filter consists of a section of coupled microstrip-line and a short-ended stub. It has a simple structure and small size (4.7×6.2 mm2), but exhibits good performance. The filter has been investigated numerically using the simulator IE3D, and samples were fabricated and measured. Measured results show that the filter has a fractional bandwidth of 103.2% (from 3.05 to 9.55 GHz) and minimal insertion loss of −0.4 dB. The measured in-band return loss is better than −15.0 dB.

Design of Compact Ultra-Wideband Filter with Low Insertion Loss and Wide Stopband

This paper proposes a compact ultra-wideband filter, which skillfully utilizes the magnetic and capacitive coupling to obtain sharp rejection. And, the filter contains a small number of lossy elements, thus the low insertion loss and compact size will not be compromised. The measured results show that the filter prototype has a measured 3dB fractional bandwidth of 128% from 2.8GHz to 11.4GHz, a minimum insertion loss of 0.3dB within the passband, a superior 20dB stopband rejection from 12.4GHz to 24GHz, and a very compact circuit size of 0.23λ×0.31λ, where λ is the guided wavelength of the microstrip structure at the center frequency f0 = 7.1GHz.

Compact Ultra-Wideband Bandpass Filter Using Dual-Line Coupling Structure

This letter presents a novel compact ultra-wideband (UWB) microstrip bandpass filter with spurious response suppression. A dual-mode ring resonator is constituted to allocate its first two resonant frequencies in the UWB band, and the dual-line parallel-coupled structure is used in this compact UWB filter, which is expected to achieve much tighter coupling degree. Simulated and measured results are found in good agreement with each other, showing a wide passband from 4.9 to 10.9 GHz, 15 dB return loss bandwidth of about 5 GHz, minimum insertion loss of 0.49 dB at 7.3 GHz, and wide upper stopband with more than 20 dB attenuation up to 20 GHz.

Ultra-wideband microstrip-slotline bandpass filter with enhanced rejection skirts and widened upper stopband

A novel ultra-wideband (UWB) bandpass filter is proposed using a multiple-mode slotline resonator and back-to-back microstrip-slotline transition. A stepped-impedance slotline resonator is constructed on the ground plane with its first three resonances occurring within the targeted UWB passband. Two microstrip feed lines are placed on the opposite plane, perpendicular to the slotline resonator, thus making up a hybrid microstrip-slotline UWB bandpass filter in the format of back-to-back transition. As its geometry is properly rearranged, a compact UWB filter with improved out-of-band performances is designed. Measured results exhibit an UWB passband from 2.95 to 10.16 GHz with mid-band insertion loss of 1.27 dB and group delay variation<0.41 ns.