Parallel Coupled-line Bandpass Research Articles

Bandwidth Enhancement of 5G Parallel Coupled Line Band Pass Filter Using Patterned Ground Structure Technique

This paper presents the design of parallel coupled line band pass filter with 10 GHz operating frequency that will be used in 5G applications. As 5G application requires big data usage and to cater the applications, the bandwidth of 5G devices need to be wider enough to support it. Thus, to improve the bandwidth performance of the designed filter, patterned ground structure (PGS) technique is implemented into it. The result shows that the bandwidth of the designed filter has been improved from 0.25 GHz to 4.98 GHz when PGS is implemented.

Design and Implementation of Parallel Coupled Line Bandpass Filter for Improvement of Return Loss Using Various EBG Structures

Design and Implementation of Parallel Coupled Line Bandpass Filter for Improvement of Return Loss Using Various EBG Structures

Spurious harmonic suppression in compact coupled-line bandpass filter with asymmetric perturbations

ABSTRACTPresent article exhibits the design of a third-order compact parallel-coupled line bandpass filter at 5.25 GHz having asymmetric perturbations to suppress the second harmonic. Initially, the effects of compactness on filter characteristics have been studied by synthesising the distributed filter network into its equivalent circuit model. The design has been initiated by computing the unit cell model, which leads to the first-order and third-order design instances with an improvement in compactness over the traditional parallel-coupled line filter. In contrary, compactness in the filter characteristics degrades the second harmonic level subject to enhanced imbalances among the odd- and even-mode velocities at the coupled lines. Subsequently, the improvement in the harmonic suppression of 53 dB and 58 dB has been achieved by incorporating different non-uniform perturbations to the outer and coupled edges of the compact filters. Accordingly, compactness of 58% and 71% have been obtained subject to the folded and in-line designs over the conventional layout.

Design of Wide-band Power Amplifier based on Power Combiner Technique with Low Intermodulation Distortion

RF power amplifiers are one of challenging blocks in designing radio frequency transceivers, this is due to non-linearity behavior of power amplifiers that leads to inter-modulation distortion. This paper presents the design of wide-band power amplifier which combined with parallel coupled line band pass filter at the input and output of power amplifier to allow the only required frequency band to pass through the power amplifier. Class-A topology and ATF-511P8 transistor are used in this design. Advanced Design System software used as a simulation tool to simulate the designed wide-band power amplifier. The simulation results showed an input return loss (S11) which less than -10dB, and gain (S21) is higher than 10 dB over the entire frequency band and considers as flat as well. The designed amplifier is stable over the bandwidth (K>1). Inter-modulation distortion is -56.919dBc which is less than -50dBc with 10dBm input power. The designed amplifier can be used for the microwave applications which include weather radar, satellite communication, wireless networking, mobile, and TV.

Compact Band-Pass Filters Based on Parallel-Coupled Lines with Open Stubs

In this paper, two parallel coupled line band-pass filters are proposed. The proposed parallel coupled line band-pass filters are composed of the parallel coupled lines and open stubs. The equivalent circuit of the proposed parallel coupled line band-pass filter is proposed and analyzed. By using odd–even mode analytical method, the design equations are derived. The relation between the center resonant frequency of the proposed band-pass filters and the electrical length is analyzed. The relation between the fractional bandwidth and the impedances is discussed. Two proposed parallel coupled line band-pass filters are designed, fabricated and measured based on the calculated results. The spurious frequencies of the proposed filters are suppressed and the transmission zeros improve the filters’ selectivity. The measured results and the simulated results show good agreement with each other, which verifies the design theory.

Unequal termination impedance parallel-coupled lines band-pass filter with arbitrary image impedance

This paper presents an analytical design for a microstrip parallel-coupled line bandpass filter (BPF) with arbitrary termination and image impedances. Using the proposed design formulas, multistage arbitrary termination impedance BPFs can be designed with a very high impedance transforming ratio (r). The fractional bandwidth and return losses are maintained even though the r and image impedance are varied. To validate the design formulas, two- and three-stage BPFs are fabricated and measure at the center frequency (f0) of 2.6 GHz. The filter 1 and filter 2 are designed with termination impedances of 50–300 Ω and 20–50 Ω, respectively. The measured results of both filters show a good agreement with the simulations. The measured passband insertion and return losses of filter 1 are better than 0.8 and 19.6 dB, respectively. Similarly, the measured passband insertion and return losses of filter 2 are better than 1.5 and 19 dB, respectively.

Design of a compact symmetricalc-Band Micro Strip Band Pass Filter with Periodic Saw tooth Grooves

Design of a miniaturized symmetrical band pass filter (BPF) using parallel-coupled half-wavelength micro strip resonators with improved stop band characteristics and 2nd harmonic suppression is presented. The proposed filter is designed at a center frequency of 5.25 GHz with a stop band insertion loss greater than-10dB at 5.15 GHz and fractional bandwidth of 20% (4.74–5.80GHz). The conventional parallel-coupled line band pass filter structure has been folded symmetrically about the horizontal plane and consecutive saw tooth periodic grooves are introduced to the parallel lines. Thus there has been a significant improvement in 2ndharmonic suppression to almost-34.51dB. Size reduction of 46.73% is accomplished with respect to the conventional filter.

COMPACT MICROSTRIP BAND-PASS FILTER FOR EMI REDUCTION

Compact microstrip band-pass filter design using parallel coupled lines is presented in this paper. The microstrip lines are calculated and constructed using CST studio with two input and output ports of the filter structure are printed over Defected Ground Structure (DGS).The proposed symmetrical structure offers a simple and compact design while exhibiting an improved stop-band characteristics in comparison to conventional coupled microstrip line filter structure. The simulation and measurements of 2GHz prototype band pass filter are presented. The measured result agrees well with the simulation data. Compared with conventional parallel coupled line band pass filter, the second, third and fourth spurious responses are suppressed; in addition, the size of the prototype filter circuit is reduced up to 20.8%.

Synthesis of Wideband Parallel-Coupled Line Bandpass Filters With Non-Equiripple Responses

This letter proposes a synthesis of wideband parallel-coupled line bandpass filters with controllable non-equiripple frequency responses. Different from the traditional Chebyshev transfer function filters, the reflection lobes of the proposed non-equiripple filters can be redistributed within the operating passband. As a result, the proposed filters have a reduced sensitivity to manufacturing errors and exhibit good tolerance control for maximum in-band reflection loss. By deriving the transfer functions, a synthesis approach with a set of nonlinear equations can be established according to the specifications such as the bandwidth and predetermined reflection lobes. Without performing any post optimization in the full-wave simulation, the non-equiripple synthesized results have less sensitivity in comparison with those obtained from traditional Chebyshev transfer functions with equiripple frequency responses.

Compact parallel-coupled line bandpass filter using double complementary split ring resonators

A novel compact parallel-coupled line bandpass filter (BPF) with complementary split ring resonators (CSRRs) is presented in this letter.The proposed BPF, with a combination of CSRRs and parallel-coupled lines, has the advantages of compact size and simpler design procedure compared with conventional CRSS BPFs. The prototype filter achieves the measured insertion loss of 1.4 dB at 3.6 GHz. The implementing area is 0.35 λg × 0.14 λg, where λg is the guided wavelength at the resonant frequency. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:506–509, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27373

Improved Microstrip Filters Using PMC Packaging by Lid of Nails

This paper shows that microstrip filters perform like textbook examples when packaged with perfect magnetic conductor (PMC). A PMC is made as a pin surface or lid of nails, and this is used to package a microstrip parallel coupled line bandpass filter. Our measurements confirm that parallel plate, cavity modes, and radiation are suppressed. This paper also includes a study of the reasons for a frequency shift between the ideal PMC packaged case and the realized case.

Parallel-coupled line filter design from an energetic coupling approach

In this study, the design of parallel-coupled line bandpass filters (BPFs) is investigated from an energetic coupling theory approach. The proposed filter design process allows the design of BPFs with improved characteristics. In particular, it is possible to implement filters with reduced occupation area, larger passband bandwidth and improved rejection performance. This is accomplished by controlling the coupling coefficient between resonators by means of the coupling section length. The suggested design technique is validated through the design, fabrication and measurement of several coupled line microstrip BPFs centred at 2.0 GHz.

Improving the stopband of microstrip parallel-coupled line bandpass filters using partially coupled resonators

An effective method is introduced to improve the stopband performance of microstrip parallel-coupled line bandpass filters. The proposed filter is constructed by adding several partially coupled resonators close to each trace in the conventional microstrip parallel-coupled line bandpass filter. The lengths of the coupled section and the stub section in each partially coupled resonator are selected such that the desired transmission zero is obtained. Proper selection of the number and the frequency of each transmission zero eventually makes it possible to suppress the unwanted spurious responses. In order to demonstrate the characteristics of the proposed filter, a third-order bandpass filter, which is centred at the operating frequency of 1 GHz with 10% fractional bandwidth, is designed, tuned, fabricated and tested. Measurement and simulation results show that the proposed prototype has a broad upper stopband performance, whereas it keeps the desired passband loss and shape almost equal to that of the conventional ones.

Characterization and dielectric behavior of B 2O 3-doped 0.9Mg 0.95Co 0.05TiO 3–0.1Ca 0.6La 0.8/3TiO 3 ceramic system at microwave frequency

The microwave dielectric properties and the microstructures of (1 − x)Mg 0.95Co 0.05TiO 3– xCa 0.6La 0.8/3TiO 3 ceramic system, prepared by a mixed oxide route, have been investigated. The sintered 0.9Mg 0.95Co 0.05TiO 3–0.1Ca 0.6La 0.8/3TiO 3 ceramics with B 2O 3 addition were characterized using X-ray diffraction spectra and scanning electron microscopy (SEM). The microwave dielectric properties are found to strongly correlate with the sintering temperature as well as the amount of B 2O 3 addition. The Q × f value of 0.9Mg 0.95Co 0.05TiO 3–0.1Ca 0.6La 0.8/3TiO 3 ceramic increased with increasing temperature to 1225 °C/4 h and decreased thereafter. The decrease in Q × f value was coincident with the abnormal grain growth. A maximum Q × f value of 76,000 GHz associated with an dielectric constant ( ɛ r ) of 22.67 and a temperature coefficient ( τ f ) of −12 ppm/°C, was achieved for samples with 0.5 wt.% B 2O 3 additions sintering at 1225 °C/4 h. By appropriately adjusting the x value in the (1 − x)Mg 0.95Co 0.05TiO 3– xCa 0.6La 0.8/3TiO 3 ceramic system, zero τ f value can be obtained. A parallel-coupled line band-pass filter is designed and simulated using the proposed dielectric to study its performance.

V-BAND HIGH ISOLATION SUBHARMONIC MONOLITHIC MIXER WITH HAIRPIN DIPLEXER

A 54{66GHz sub-harmonic monolithic passive mixer using the standard 0.15m pHEMT process is demonstrated. The proposed mixer is composed of a hairpin diplexer, an open stub, and a low-pass fllter. The mixer also utilizes a pair of anti-parallel diodes to achieve a subharmonic mixing mechanism. The hairpin diplexer formed with two parallel-coupled line band-pass fllters is used to improve the isolation between the radio frequency (RF) and local oscillation (LO) ports. The low-pass fllter supports an intermediate frequency (IF) ranging from dc to 1GHz. This proposed conflguration leads to a die size of less than 1.5mm 2 . With a conversion loss of 15.2{18.3dB, the 2LO- to-RF isolation is found to be better than 27.5dB. A high LO-to-RF isolation of 23.5{45dB over 54{66GHz RF bandwidth, as well as 1dB compression power of 8dBm, can be achieved.

New dielectric material system of La(Mg 1/2Ti 1/2)O 3–Ca 0.6La 0.8/3TiO 3 for microwave applications

The microstructure and microwave dielectric properties of xLa(Mg 1/2Ti 1/2)O 3–(1 − x)Ca 0.6La 0.8/3TiO 3 ceramics system with ZnO additions (0.5 wt.%) investigated by the conventional solid-state route have been studied. Doping with ZnO (0.5 wt.%) can effectively promote the densification and the dielectric properties of xLa(Mg 1/2Ti 1/2)O 3–(1 − x)Ca 0.6La 0.8/3TiO 3 ceramics. 0.6La(Mg 1/2Ti 1/2)O 3–0.4Ca 0.6La 0.8/3TiO 3 ceramics with 0.5 wt.% ZnO addition possess a dielectric constant ( ɛ r ) of 43.6, a Q × f value of 48,000 (at 8 GHz) and a temperature coefficient of resonant frequency ( τ f ) of −1 ppm/°C sintering at 1475 °C. As the content of La(Mg 1/2Ti 1/2)O 3 increases, the highest Q × f value of 62,900 (GHz) for x = 0.8 is achieved at the sintering temperature 1475 °C. A parallel-coupled line band-pass filter is designed and simulated using the proposed dielectric to study its performance.

New Synthesis of Parallel-Coupled Line Bandpass Filters With Chebyshev Responses

Parallel-coupled line filters with Chebyshev passbands are synthesized based on the insertion-loss functions derived by converting the composite ABCD matrices of all coupled stages. With the synthesis, both the electromagnetic simulation and measurement results have accurate in-band response and bandwidth. Simultaneous equations for Chebyshev filters of order N les 9 are derived for determining geometric parameters of the coupled stages. The tradeoff between circuit bandwidth and ripple level is discussed. In experiments, three planar or quasi-planar structures, including the coupled-line with aperture in the ground plane, the three-line microstrip, and the broadside-coupled lines, are employed to realize the end stages for implementing the high coupling levels. Experimental filters of order up to nine with fractional bandwidth of 30% or 40% are fabricated and measured. The results show good agreement with predictions by the theory and simulation.

Dielectric properties and applications of low loss (1−x)(Mg0.95Co0.05)TiO3–xCa0.8Sm0.4/3TiO3 ceramic system at microwave frequency

In this paper, the microstructures and microwave dielectric properties of the (1 − x )(Mg 0.95 Co 0.05 )TiO 3 – x Ca 0.8 Sm 0.4/3 TiO 3 ( x = 0.05–0.2) ceramic system were investigated. Ca 0.61 Sm 0.78/3 TiO 3 increased the dielectric constant ( ɛ r ), reduced the quality factor ( Q × f value) and also compensated the temperature coefficient of resonant frequency ( τ f ) of (Mg 0.95 Co 0.05 )TiO 3 . The microstructures of (1 − x )(Mg 0.95 Co 0.05 )TiO 3 – x Ca 0.8 Sm 0.4/3 TiO 3 ceramics were characterized by X-ray diffraction patterns, scanning electron microscope (SEM). The existing areas of different compositions in the ceramics were observed by means of energy dispersive spectroscopy (EDS), which revealed that Ca 0.8 Sm 0.4/3 TiO 3 as minor phase co-existed with (Mg 0.95 Co 0.05 )TiO 3 . The existing Ca 0.8 Sm 0.4/3 TiO 3 phase can inhibit the grain growth of the main (Mg 0.95 Co 0.05 )TiO 3 phase. A dielectric constant ( ɛ r ) of 22.5, a Q × f value of 108,000 (at 8 GHz ) and a τ f value of −8 ppm/°C were obtained for 0.9(Mg 0.95 Co 0.05 )TiO 3 –0.1Ca 0.8 Sm 0.4/3 TiO 3 ceramic sintered at 1275 °C for 4 h. Moreover, an ISM band parallel-coupled line band-pass filter with a central frequency of 5.8 GHz was also designed and fabricated using the proposed material as substrate to study its performance. It also showed a substantial reduction in both insertion loss and size in comparison with other dielectrics FR4 and alumina.

결함 기저면 구조 인버터를 이용한 평행 결합 선로 대역 통과 필터

In this paper, the novel method is proposed to realize the parallel coupled line band pass filter using defected ground structure(DGS) inverter. This method provides simple solution which easily resolves the limit of line width happened due to high impedance on the occasion of designing filter composed of line inverter. On the basis of the proposed method and conventional method, the band pass filters haying 13.3% fractional bandwidth were designed and implemented. The measured data of two filters show usually good agreement with each other, but on the other hand the length of proposed filter become shorten about 15mm and the width of inverter line was expanded two times or more in comparison with conventional filter.

Corrugated parallel-coupled line bandpass filters with multispurious suppression

Corrugated coupled stages are devised to design bandpass filters with multispurious suppression. Through two-port analysis, the suppression is found critically dependent on equality of the even and odd mode phase velocities at even harmonics of design frequency fo. Quarter-wave (λ/4) corrugated stages are tuned to allocate inherent transmission zeros at both 2fo and 4fo, and 6fo for some structures, so that the circuit is free of spurious at these frequencies. Coupled stages with proper coupling lengths are arranged to cancel unwanted peaks at 3fo, 6fo and 7fo, and tapped input/output scheme is employed to tackle those at 3fo and 5fo. Measured data of designed filters show rejection levels better than 30 dB in upper stopband. Three circuits are fabricated and measured to demonstrate the idea.