Compact Microstrip Lowpass Filter Research Articles

Composite microstrip lowpass filter with ultrawide stopband and low insertion loss

ABSTRACTA compact microstrip lowpass filter with a very wide passband is proposed in this article. The filter is based on generalized Chebyshev filter prototype of nine degree. The filter is designed to have a cut‐off frequency at 18 GHz and a return loss of better than 20 dB. The design of the proposed filter is successfully realized in theory and verified by full‐wave electromagnetic simulation and the experiment. An excellent agreement between the expected and measured results is obtained. The measured results show a low insertion loss of less than 1.5 dB over the entire ultrawide passband. The fabricated filter looks attractive for wideband RF/microwave systems due to its good performance and overall physical volume. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:871–874, 2015

A Novel Compact Microstrip Lowpass Filter with Sharp Transition and Improved Stopband

A novel compact microstrip lowpass filter (LPF) is proposed in this paper, which consists of the complementary rectangle split ring defected microstrip structure (CRSR-DMS), open stubs, spurline and the dumbbell-shaped defected ground structure (DGS). Due to the unique response of the presented CRSR-DMS, a low passband insertion loss and a sharp transition of the proposed LPF was achieved. Meanwhile, an improved stopband was obtained by properly adjusting the working frequencies of open stubs, a third-order LPF using spurline and dumbbell-shaped DGS. The measured result of the designed LPF shows that attenuation rate reaches 159 dB/GHz and a wide stopband is obtained from 4.07 GHz to more than 15 GHz. DOI: http://dx.doi.org/10.11591/telkomnika.v13i1.6760 Full Text: PDF

Compact lowpass filter with wide stopband bandwidth

ABSTRACTA compact microstrip lowpass filter (LPF) which consists of a meander line, a coupled line and two open stubs is proposed. The mechanism for reallocating filter transmission zeros and the design procedure are explained. The simulated and measured results demonstrate that this LPF provides compact size, low insertion loss, and wide stopband. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:367–371, 2015

Design of compact microstrip lowpass filter with ultra-wide stopband using modified T-shaped resonator

A new microstrip lowpass filter with compact size and ultra-wide stopband using T-shaped resonator is proposed. To make smaller the circuit size of the filter, cursive transmission line is also suggested. Moreover, exact equation of most important transmission zero is calculated based on LC equivalent circuit and transformation function. A demonstration filter with 3 dB cut-off frequency at 1.02 has been designed, fabricated, and measured. Results show that a relative stopband band width of 166.3% (referred to suppression degree of 20 dB) is achieved while obtaining high figure of merit of 46 274.

Compact lowpass filter with a sharp roll‐off using patch resonators

ABSTRACTThis article presents a new compact microstrip lowpass filter with sharp roll‐off and ultrawide stopband using funnel and triangular patch resonators. The patch resonators are placed symmetrically about a high impedance central microstrip line. The filter has been designed and fabricated using a very low cost material. The experimental results show a good agreement with the simulated results and demonstrate that, the sharp roll‐off and good stopband performance is obtained by the proposed filter. The 3 dB cutoff frequency of the proposed filter is at 5.55 GHz with a roll‐off of 84 dB/GHz and its stopband extends up to 11.8 GHz. The filter has an ultra compact size of 9.4 × 8 mm2. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2534–2536, 2014

Compact microstrip lowpass filter with sharp roll‐off using radial resonator

A compact microstrip lowpass filter (LPF) with sharp roll-off is presented. The proposed filter consists of radial resonator, triangular patch and open stub. The proposed filter has good specifications such as low insertion loss <0.1 dB, high return loss of −20 dB, wide stopband from 4.37 to 19 GHz with −20 dB attenuation level and compact size. The LPF filter has a cut-off frequency of 3 dB at 4.24 GHz and a high roll-off rate of 130.7 and finally a high figure-of-merit of 23526.

Compact microstrip low-pass filter with sharp selection characteristics using triple novel defected structures for UWB applications

In this article, a novel band-stop filter using defected ground structure (DGS) and defected microstrip structure (DMS) with triple T-shaped slot and a pair of protruded T-shaped strips inside the triple rectangular slots is presented. Using these DGS and DMS slots, a quasielliptic low-pass filter (LPF) was designed, fabricated, and tested. The transmission zeros of the slots can be easily controlled by changing the protruded T-shaped strip and slot dimensions, without changing the area taken by the structure. The experimental results show good agreement with simulation results and demonstrate that excellent stop-band performance could be obtained through the proposed LPF. The filters have a cutoff frequency of about 3.14 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1007–1010, 2014

Design of broad‐stop band low pass filter using a novel quasi‐Yagi‐DGS‐resonators and metal box‐technique

AbstractA novel 1.8 GHz compact microstrip low pass Filter (LPF) based on quasi‐Yagi defected ground structure (DGS) and compensated capacitors is proposed in this article. The filter has a very sharp cut‐off frequency response with low insertion loss and achieves a wide reject band with overall 20 dB attenuation from 2.8 GHz up to 10 GHz. The equivalent circuit model of Yagi‐DGS unit is derived using AWR software and the circuit parameters are extracted by using a simple circuit analysis method. The advantage of this structure is that the reject band can be controlled by tuning the dimension of yagi‐arms at higher frequency rang. To improve the filter characteristics in reject band, a new metal box has been used to minimize the loss in pass band and to extend the reject band. The proposed LPFs are designed and fabricated. The compact filter occupies an area of (0.45 λg × 0.35 λg) with λg = 44 mm. A comparison between simulation and measurement results confirms the validity of the LPF configuration and design procedure. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:523–528, 2014

Compact microstrip lowpass filter with wide stopband and sharp roll-off using tapered resonator

In this article, a novel microstrip lowpass filter (LPF) with specifications such as sharp cut-off, wide stopband, low insertion loss and high return loss using tapered resonator is presented. The LPF has cut-off frequency of 1.11 GHz, where unwanted harmonics are suppressed by novel tapered cells. The bandwidth is enhanced, and the size is reduced as compared to the conventional tapered filter. The transition band is approximately 0.29 GHz from 1.11 to 1.4 GHz with corresponding attenuation levels of –3 and –20 dB, respectively. The stopband with greater than –20 dB rejection is from 1.4 to 8.9 GHz, insertion loss in the passband is less than 0.1 dB, return loss is less than –18 dB and the overall size of the filter is 0.12 × 0.073 λg. The proposed filter is fabricated and measured. The simulation and measurement results are in good agreement. This LPF is designed for microwave communication applications, especially wireless video transmitters.

Realisation of highly compact planar lowpass filter for UWB RFID applications

A novel compact microstrip lowpass filter is described that exhibits an quasi-elliptical function response with high out-of-band rejection for integration in ultra-wideband (UWB) chipless radio frequency identification (RFID) receivers. The filter's characteristics include a wide-stopband and low passband insertion loss with a passband ripple of 0.03 dB. Out-of-band attenuation of 30 dB is achieved up to about four times the cutoff frequency (4f c), and 20 dB up to about seven times the cutoff frequency (7f c). In addition, the proposed filter structure offers a high figure-of-merit of 8657 that exceeds the lowpass planar filters with an equal cutoff frequency reported in the literature to date.

A novel compact microstrip lowpass filter with wide rejection band and sharp transition band using diamond-shaped resonator

In this paper, a novel compact microstrip lowpass filter (LPF) using diamond-shaped resonator with wide rejection and sharp transition band is presented. The proposed filter has −3 dB cut off frequency at 2.6 GHz. The maximum insertion loss is only 0.1 dB in the passband and the rejection band extends from 2.89 to 20.84 GHz with the attenuation level better than −21 dB. The transition band is only 0.288 GHz, from 2.606 to 2.894 GHz with corresponding attenuation levels of −3 and −20 dB, respectively. The filter size is 12.4 × 11.5 mm2. The proposed filter is fabricated and tested, where the measurement results are in good agreement with the simulation results. The proposed LPF has compact size, simple structure, wide rejection band, and low insertion loss, where all of these characteristics are essential for LPF in the modern communication circuits.

Compact microstrip lowpass filter with sharp roll‐off and ultra‐wide stop‐band

A compact microstrip lowpass filter (LPF) with sharp roll-off and ultra-wide stop-band bandwidth is presented. The structure consists of high-impedance meandered transmission lines loaded by triangular and polygonal resonant patches. The cutoff frequency of the proposed LPF is 2.44 GHz and the measured results show good performance such as sharp roll-off, good insertion loss and an ultra-wide stop-band from 2.53 to 35 GHz with the insertion-loss higher than 20 dB. There is a good agreement between the electromagnetic-simulation and measurement results.

Microstrip Lowpass Filter with Very SharpTransition Band Using T-Shaped, Patch, and Stepped Impedance Resonators

A compact microstrip lowpass filter (LPF) with an elliptic function response is proposed. A high equivalent capacitance and inductance between the structures of the resonator result in the sharp transition band of 0.04 GHz from 4 GHz to 4.04 GHz with an attenuation level of −3 dB and −20 dB, respectively. To improve the LPF rejection band, multiple open stubs are connected to the proposed resonator. A filter with a 3-dB cut-off frequency at 4 GHz is designed, fabricated, and measured, and agreement between the measured and simulated results is achieved. The results show that a stopband bandwidth of 131% with a suppression level better than −20 dB is obtained while achieving a compact size with a wide stopband.

Design and validation of low-pass filter using microstrip stub and defected ground structure

In this article, a compact microstrip low-pass filter using conventional elliptical headed dumbbell-shaped defected ground structure (DGS) is presented.The proposed structure with main dimension parameters has been analyzed as a design guide, which can be used to fabricate the filter in future. The H-shape open stub increases the equivalent parallel capacitance to improve the out-band suppression. The proposed LPF shows low cut-off frequency response, low insertion loss, sharp transition, and fairly good rejection in stop band. For the five-array DGS filter, including stubs provides the rejection in stop band from 2.8 GHz to higher frequencies. DGSs have shown increasing potential for implementation in different applications: microwave integrated circuit (MIC), monolithic microwave integrated circuit (MMIC), and radio frequency integrated circuit (RFIC). They provide sharp, distinct electromagnetic band-gap, and high slow wave factor, which lead to smaller size circuits and takes lots of engineering challenges. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:571–573, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27361

Compact Microstrip Low-pass Filter with Wide Stop-band and Sharp Roll-off

This paper presents a novel compact microstrip low-pass filter with wide stop-band and sharp roll-off. The structure consists of a transmission line, loaded with coupled novel Hairpin units. The cut-off frequency of the proposed filter is 2.9 GHz. The measured results show good LPF performance such as sharp roll-off skirt, low insertion-loss, high return-loss in the pass-band and wide upper stop-band of 3.2 to 16.1 GHz with an insertion-loss higher than 20.0 dB. The measured values and the EM-simulation results are in good agreement.

Compact LowPass Filter with Wide StopBand Using Non-Uniform Microstrip Resonant Cells

In this paper, a novel compact microstrip lowpass filter is designed. The proposed filter which is etched on the 50 Ω microstrip line consists of four non-uniform 1-D microstrip photonic bandgap (PBG) cells with different cutoff frequency.. The demonstration lowpass filter with 2.2 GHz cutoff frequency is designed, fabricated and measured. The measurement results show that the band rejection effect is better than -20 dB from 2.8 GHz to 10 GHz, the insertion is less than 2 dB, and the length of filter is 5.6 cm long. Compared with the conventional filter, the proposed filter has smaller size. Meanwhile, it overcomes the problems of narrow stop-band and low harmonic suppression. Furthermore, the impedance matching is not need to be considered. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Wide-stopband microstrip low-pass filter using modified semi-circle patch resonator

In this article, a compact microstrip low-pass filter with elliptic-function response is proposed. To achieve wide stopband, modified semi-circle patch resonator in series with semi-circle stepped impedance resonator is used. The proposed structure achieves a wide stopband and a high selectivity within a small circuit area. The proposed filter has 3-dB cutoff frequency at 1.71 GHz and 20 dB rejection at 2.1 GHz. The stopband with the attenuation level better than −18.7 dB is from 2.08 up to 16 GHz, and consequently we have reached the high and wide rejection in stopband as well as compact size. The structure is simulated, fabricated and measured. The measured results are in good agreement with the simulated results.

Design of compact microstrip lowpass filter with ultra-wide stopband

A new microstrip lowpass filter with compact size and an ultra-wide stopband is proposed. To achieve compact size and ultra-wide band rejection, both triangular patch resonators and radial patch resonators are introduced in the filter. To reduce the circuit size of the filter further, meander transmission lines are also adopted in the design. A demonstration filter with 3 dB cutoff frequency at 1 GHz has been designed, fabricated and measured. Results indicate that the proposed filter can suppress the sixteenth harmonic response referred to a suppression degree of 15 dB. Furthermore, the proposed filter exhibits a small size of 0.111 λg×0.091 λg, where λg is the guided wavelength at 1 GHz.

Compact microstrip lowpass filter for harmonics suppression using a new defected ground structure

AbstractA compact microstrip lowpass filter (LPF) for harmonics suppression is proposed. An open stub LPF with uniquely shaped defect ground structure cells is used to optimize the LPF performance. A stopband attenuation of greater than 20 dB is obtained from 3.42 GHz to more than 18 GHz. The physical size of the proposed LPF, excluding transmission lines, is only 10 × 15 mm2. Good agreements between simulation and measurements are observed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1385–1387, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26809

Design of Compact Ultra-Wide Stopband Lowpass Filter Using a U-Slotted Ground Structure (SGS) and Multilayer-Technique

A compact microstrip lowpass filter using a U-SGS, which has the same meaning as U-Defected Ground Structure (U-DGS), with compensated microstrip is proposed in the paper. The equivalent circuit for the proposed Ushaped DGS and its corresponding L-C parameters are extracted by using its Sparameters response and a simple circuit analysis method. The lowpass filter using three cascaded U-DGS provides a compact size, very good transition sharpness with low insertion loss in passband and wide rejection in the stopband. Measured results show good agreement with the theoretical results. New ideas in order to improve the compactness and the losses of the filter have been proposed. The article presents some promising patents on design of compact ultra-wide stopband lowpass filter using a U-slotted ground structure (SGS) and multilayer-technique. Keywords: Defected ground structure, lowpass filter, multiplayer-technique, reject band, sharp transition, U- resonator, U - Slotted Ground Structure, Ultra-Wide Stopband Lowpass Filter, U-DGS SLOT STRUCTURE, U-DGS SLOT, DESIGN AND FABRICATION