Proposed Ultra-wideband Bandpass Filter Research Articles

Design of miniaturized single and dual-band bandpass filters using diamond-shaped coupled line resonator for next-generation wireless systems

AbstractThis paper presents a multi-mode resonator (MMR) for next-generation wireless systems that achieves single and dual-band bandpass filter (BPF) responses using a split-ring dual-path structure. The proposed BPF design is realized by employing two pairs of parallel couple lines and two symmetrical step-impedance open-circuited stubs (SIOCS). SIOCS are used to improve selectivity and increase the number of transmission zeros/poles. The proposed single-band BPF exhibits an ultra-wideband (UWB) response having a center frequency of 7.5 GHz, a minimum insertion loss of less than 0.48 dB, and a maximum return loss of 25.35 dB. The proposed UWB BPF has a stopband suppression of 39.34 dB up to 18 GHz and a 3 dB fractional bandwidth of 48.23%. Moreover, a dual-band BPF has been accomplished by utilizing the same architecture while slightly changing the MMR structure and adding more coupling. The center frequency (bandwidth) of the dual broadband BPF is 7.40 GHz (2.40 GHz) and 14.15 GHz (1.7 GHz), respectively. The measured minimum insertion loss is less than 0.23 dB and a return loss of less than 16.8 dB with 3 dB FBWs of 32.4 and 12.1%. Finally, two prototypes are fabricated to validate the proposed characteristics. The BPF's simulated and measured results are in good agreement.

An On-Chip Ultra-Wideband Bandpass Filter in 0.18-μm SiGe BiCMOS Technology

This letter presents an on-chip ultra-wideband (UWB) bandpass filter (BPF) in 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> SiGe BiCMOS Process. The proposed UWB BPF is constituted by cascaded quasi-elliptic response high-pass filter (HPF) and low-pass filter (LPF). A series <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> circuit is introduced in the classical fifth-order lumped-element HPF, so that a transmission zero (TZ) is generated to form quasi-elliptic response. The microstrip line LPF with two series of open stubs can generate another two TZs, which also result in quasi-elliptic response. Step-to-step design procedure is given to guide the UWB BPF design. The measured result shows that the fabricated UWB BPF covers the frequency range of 10 – 50 GHz with the in-band return loss better than 13.5 dB, and the minimum in-band insertion loss is 1.99 dB. The core size of fabricated UWB BPF is 382 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}\,\,\times 428\,\,\mu \text{m}$ </tex-math></inline-formula> excluding testing pads.

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.

Compact reconfigurable triple notch ultra-wideband bandpass filter for cognitive radio system

This paper introduces a compact ultra-wideband (UWB) bandpass filter (BPF) with two switchable external notch structures which avoids the interference between the UWB communication with worldwide interoperability for microwave access (WiMAX) and wireless local area network (WLAN) systems, suitable for cognitive radio (CR) applications. The first external notch structure is modified C-shaped structure which generates a sharp rejection at 3.5 GHz to avoid interference with WiMAX system and second external notch structure is back to back T-shaped structure which creates sharp rejection notch bands at 5.2 GHz and 5.8 GHz frequencies for WLAN systems. The filter reconfiguration is achieved by varying the conductance of microstrip line. The response of the proposed structure shows sharp rejections at one WiMAX and two WLAN bands. The bandpass filter covers frequency of UWB system from 3.1 to 10.7 GHz having very low passband insertion loss. The proposed UWB BPF is designed, simulated, fabricated and tested to validate the results. A good agreement is achieved between simulation and experimental results.

Compact reconfigurable triple notch ultra-wideband bandpass filter for cognitive radio system

This paper introduces a compact ultra-wideband (UWB) bandpass filter (BPF) with two switchable external notch structures which avoids the interference between the UWB communication with worldwide interoperability for microwave access (WiMAX) and wireless local area network (WLAN) systems, suitable for cognitive radio (CR) applications. The first external notch structure is modified C-shaped structure which generates a sharp rejection at 3.5 GHz to avoid interference with WiMAX system and second external notch structure is back to back T-shaped structure which creates sharp rejection notch bands at 5.2 GHz and 5.8 GHz frequencies for WLAN systems. The filter reconfiguration is achieved by varying the conductance of microstrip line. The response of the proposed structure shows sharp rejections at one WiMAX and two WLAN bands. The bandpass filter covers frequency of UWB system from 3.1 to 10.7 GHz having very low passband insertion loss. The proposed UWB BPF is designed, simulated, fabricated and tested to validate the results. A good agreement is achieved between simulation and experimental results.

A compact ultra wide band bandpass filter with dual band notch designed based on composite right/left‐handed transmission line unit cell

In this article, we propose an ultra wide band (UWB) bandpass filter with dual notch characteristics. The proposed filter is designed based on composite right/left handed (CRLH) transmission lines. The filter is having a compact size of 2.4 mm × 8.78 mm and printed on FR4 material with relative permittivity 4.4 with thickness 1.6 mm. The filter is constructed by series of strip lines, which forms interdigital capacitance and shunt inductors allowing both low and high frequencies of the UWB to pass. The selectivity in lower and higher parts of the UWB is achieved by the slots etched from the ground plane. The dual band notch is obtained at 4 GHz and 7 GHz using the L-shaped strip lines on both sides of the filter. The comparative analysis of the proposed UWB band pass filter without and with notch characteristics is presented with the help of the S11 and S21 curves.

A highly selective UWB bandpass filter using stepped impedance stubs

AbstractWe present a new ultra-wideband (UWB) band-pass filter (BPF) configuration with a stepped impedance short-circuited stub (SISS)-loaded triple-mode resonator (TMR) and stepped impedance radial stub (SIRS). The novel SISS-loaded TMR and SIRS improve the roll-off ratio at both ends. Even though this UWB BPF is based on a single resonator, the measured results show excellent in-band performance with a small insertion loss less than 0.6 dB and return loss greater than −16 dB. The proposed UWB BPF has sharp roll-off ratio of 96 and 43 dB/GHz, respectively, at the lower and upper edges of the pass-band, and a wide stop-band from 10.8 to 15.6 GHz with the rejection greater than 20 dB.

Design of two-stage fish spear-shaped UWB bandpass filter with sharp selectivity and good out-of-band performances

In this paper, a novel two-stage fish spear-shaped multimode resonator (MMR)-based ultra wideband (UWB) bandpass filter (BPF) is presented. The fish spear-shaped MMR is loaded with stepped impedance resonator in order to improve the out-of-band performance of the proposed filter. The proposed UWB BPF filter has fractional bandwidth better than 110%. In order to validate the present design approach, the filter is fabricated on RT/Duroid 5880 having dielectric constant 2.2, thickness 0.787 mm and loss tangent of 0.0009. The measured passband bandwidth of the filter is from 3.3 to 11.85 GHz, with insertion loss of 1.5 dB and return loss better than 12 dB in the passband. The proposed filter has sharp selectivity and upper stopband with 20 dB attenuation from 12 to 24 GHz.

Design of a Compact UWB Bandpass Filter using Via-Less CRLH TL

A novel compact ultra wideband (UWB) bandpass filter (BPF) based on composite right/left handed transmission line (CRLH TL) is reported in this paper. The proposed UWB BPF is designed and developed by coupling of two unit-cells of via-less CRLH TL, excited by asymmetrical coplanar waveguide (CPW) feed-line. The unit cell of CRLH TL is designed using series interdigital capacitor (IDC) in shunt with the shorted inductive stub. Because of the CPW-fed, no via is required to get the shunt inductance for the realization of CRLH TL, which minimizes the fabrication steps. The filter is compact in size 11.9 x 6 mm 2 . The proposed filter exhibits the return-loss (|S 11 |) more than 11.2 dB and insertion-loss (|S 21 |) less than 0.5 dB and low and flat group delay response throughout the passband, 3.3 GHz to 13.0 GHz. The proposed UWB BPF also shows the good stopband rejection (|S 21 | > 20 dB and |S 11 | < 0.8 dB) from 13.6 GHz to 15 GHz and steep roll-off from passband to stopband. The fractional bandwidth (FBW) of the filter is found to be 119 %. The equivalent lumped circuit model of the filter is obtained through Ansoft Designer. All simulated results are extracted through method of moment based simulator, IE3D. Agilent vector network analyzer (VNA) is used to get the measured results. All measured results are found in close similarity with the simulated results.

A Compact UWB Bandpass Filter using Hybrid Fractal Shaped DGS

In this paper, a novel compact ultra wideband (UWB) bandpass filter (BPF) based on fractal-shaped defected ground structure is designed and developed with more than -20 dB out-of-band rejection level. It is made of stepped impedance line and composite right/left handed-transmission line (CRLH-TL) constructed with capacitive gap in conductor strip and a hybrid fractal-shaped ring slot in ground plane. The proposed UWB bandpass filter has good passband performance with -10 dB return-loss bandwidth of 2.2 GHz to 10.6 GHz with fractional bandwidth of 131%. The prototype of proposed filter is fabricated and measured. Good agreement is seen between simulated and measured results. The designed and developed filter is compact in size, simple in geometry and owns good S-parameters performance characteristics in both passband as well as in stopband. Return-loss better than 10 dB and insertion-loss less than 0.4 dB (except at some higher frequency) is obtained throughout the passband whereas, in stopband, insertion-loss more than 20 dB and return-loss better than 0.8 dB is observed up to the stopband frequency of 20 GHz. Moreover, UWB BPF also shows the flat group delay (variation ≤ 0.75 ns) performance. Thus the proposed filter can be a useful candidate for low profile future wireless communication systems.

An ultra-wideband (UWB) bandpass filter with complementary split ring resonator for coupling improvement

This paper presents a novel, compact & low cost ultra-wideband (UWB) bandpass filter (BPF) using folded coupled stepped impedance resonator (SIR) pairs and a complementary split ring resonator (CSRR). Based on the advantage of symmetry of the structure, the odd-even mode decoupling scheme is applied for the analysis of different resonant modes which is generated by the coupled SIR pairs. The overall coupling of the proposed BPF is made stronger by placing a modified CSRR unit cell in the ground plane and it is confirmed through circuit analysis, coupling architecture & field distribution analysis. The proposed UWB filter provides 108% measured 3dB fractional bandwidth (FBW) & insertion loss 1.6–2.1dB in the passband (2.6–10GHz) with a minimum flat group delay of 0.2ns. The proposed UWB BPF is fabricated using commercially available FR4 substrate (εr=4.4 , h=0.8mm) and a good agreement is found between the simulated and measured results.

A compact UWB bandpass filter based on CRLH via‐less CPW‐fed

ABSTRACTA novel compact coplanar waveguide (CPW)‐fed ultrawideband (UWB) bandpass filter is proposed in this article. The composite right‐/left‐handed transmission line structure is designed on a single layer via‐less CPW‐fed, which reduces the fabrication complexity and makes the structure more feasible. The filter exhibits stopband rejection level greater than 10 dB while maintaining insertion loss less than 0.3 dB throughout the passband range. The filter has a compact size of 18.4 mm × 4.5 mm. The performance of the proposed UWB bandpass filter is compared with the previously reported UWB bandpass filters. All the performance parameters of the filter are evaluated by full‐wave electromagnetic simulator IE3D, based on the method of moments and all the results are verified by measurement. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:276–279, 2016

UWB bandpass filter with quad notched bands

ABSTRACTA novel ultrawideband (UWB) bandpass filter (BPF) with a quad band‐notched function is investigated using a modified H‐shaped resonator. The proposed H‐shaped resonator, which exhibits quadruple resonance characteristics, is realized without any change in its overall size by modifying the simplified composite right/left‐handed resonator exhibiting dual resonance characteristics. The proposed resonator is integrated into a conventional UWB BPF. The notching frequencies are located at 2.41, 3.42, 5.3, and 5.9 GHz, and the attenuations at the center frequency of the four notched bands are at least 13 dB. The proposed UWB BPF has the advantages of compact size, low insertion loss, good selectivity, and flat delays. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2286–2289, 2014

Compact ultra‐wideband bandpass filter using quad‐T‐stub‐loaded ring structure

ABSTRACTA compact ultrawideband (UWB) planar bandpass filter (BPF) using quad‐T‐stub‐loaded ring resonator is presented. At this filter, two sets of the four high impedance lines at the two sides of the ring as the coupling fed structure are used to gain much stronger coupling effect. Compared with the conventional ring resonator filter, the bandwidth of the UWB BPF can be improved after we load four T‐shaped stubs on the ring resonator. That is because these stubs can increase the effective electrical lengths, and also lower the second and third resonant frequencies of the ring resonator at no expense of the size increase. Finally, a prototype of the proposed UWB BPF with 3 dB fractional bandwidth of 101% has been designed and fabricated. The measured results are in good agreement with the full‐wave simulations. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1988–1991, 2014

Compact ultra‐wideband bandpass filters with narrow notched bands based on a ring resonator

In this study, compact ultra-wideband (UWB) bandpass filters with single/dual-notched bands are proposed based on a ring resonator and transversal signal-interference concept. Broad passband and narrow notched bands with controlled even/odd-mode resonator frequencies can be adjusted conveniently by changing the characteristic impedance of the ring resonator. Transmission zeros are introduced to improve selectivity and harmonic suppression of the proposed UWB bandpass filters with notched bands. To verify the presented strategies, three prototypes (er = 2.65, h = 0.5 mm) with 3 dB fractional bandwidth >120% are designed and fabricated. Simple structure and good in/out-of-band performances can be achieved in the proposed UWB bandpass filters.

Ultra-wideband bandpass filter using simplified dual composite right/left-handed transmission line structure

A simplified dual composite right/left-handed (SD-CRLH) transmission line (TL) structure is proposed and analyzed in this article.The SD-CRLH TL with only capacitor in series is a left-handed (LH) highpass filter, while the SD-CRLH TL with only inductor in series is a right-handed (RH) lowpass filter. By combining them together, a bandpass filter (BPF) can be realized. As an example, an ultra-wideband (UWB) BPF is designed and simulated using the SD-CRLH TL structures, and finally fabricated by the standard printed circuit board process. The measurements show that the proposed UWB BPF has a passband from 3.1 to 10.6 GHz with a group delay variation of less than 0.13 ns, and the insertion loss is less than 1.5 dB over the passband. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1165–1167, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27508

UWB Bandpass Filter with One Tunable Notch-Band Based On DGS

An ultra-wideband (UWB) band-pass filter (BPF) with an electronically tunable notch-band based on defected ground structure (DGS) is investigated in this paper. The proposed UWB BPF comprises four folded shunt quarter-wavelength short-circuited stubs, one DGS and a varactor diode with dc bias. The DGS is studied and employed to generate one desired notched band. The predicted results are compared with measured data, and good agreement is reported.

Compact ultra-wideband bandpass filters using half-wavelength slotline resonators

In this study, the authors investigate compact half-wavelength slotline resonators and its applications to compact ultra-wideband (UWB) bandpass filter designs. The circuit models have been developed for the proposed UWB bandpass filters. By introducing additional slotlines and properly rearranging the filter geometry, the passband frequency response and upper stopband performance are improved. The basic filter and modified UWB filter have been designed, fabricated and validated to demonstrate the proposed design methodology. Their calculated, simulated and measured results show good agreement. The modified UWB filter has extremely compact size of 8.5 mm×7 mm. Both simulated and measured results show that the fabricated modified UWB filter has an UWB passband with a fractional bandwidth of 117.8%.

A Compact UWB Bandpass Filter With Embedded SIR as Band Notch Structure

In this letter, an ultrawideband (UWB) bandpass filter with a band notch is proposed. The UWB BPF (3.1-10.6 GHz) is realized by cascading a distributed high-pass filter and an elliptic low-pass filter with an embedded stepped impedance resonator (SIR) to achieve a band notch characteristic. The notch band is obtained at 5.22 GHz. It is shown that the notch frequency can be tuned by changing the impedance ratio of the embedded SIR. A fabricated prototype of the proposed UWB bandpass filter is developed. The inband and out-of-band performance obtained by measurement, EM simulation, and that with an equivalent circuit model are in good agreement.

Novel ultra-wideband coplanar-waveguide bandpass filter with inductance-loaded Y-shaped resonators

A novel ultra-wideband (UWB) coplanar waveguide (CPW) bandpass filter (BPF) with the inductance-loaded Y-shaped resonator has been presented in this letter.The proposed UWB BPF has been constructed by integrating the broadside-coupled microstrip-CPW structures into the inductance-loaded Y-shaped resonator. The broadside-coupled microstrip-CPW structures can get tight coupling for UWB performance. The external quality factor has been analyzed to design the proposed UWB filter. An UWB CPW BPF is designed, simulated, and fabricated to demonstrate the performance of the proposed filter structure. The measured results show good agreement with the simulated ones. The fabricated UWB CPW BPF exhibits excellent performance, including 3-dB insertion loss and 10-dB return loss bandwidths over the entire UWB band with a minimum insertion loss of 0.37 dB at 5.4 GHz, as well as 1-dB insertion loss bandwidth of 3.25–10.2 GHz and group delay variation from 0.18 to 0.28 ns over the frequency range of 3.9–11 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1134–1137, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25940