Compact U-shaped dual planar EBG microstrip low-pass filter

In this paper, a novel high-performance compact dual planar electromagnetic bandgap (DP-EBG) microstrip low-pass filter with a U-shaped geometry is proposed. By employing the unique DP-EBG configuration and the U-shaped geometry of the microstrip line (MLIN), the proposed structure achieves a wide stopband with high attenuation and a high selectivity within a small circuit area. Its passband ripple level is low due to the U-shaped geometry and the electromagnetic bandgap (EBG) structure with square patches inserted at the bends of the MLIN. The Chebyshev tapering technique is used to taper components of the proposed structure in order to eliminate ripples caused by the EBG periodicity. The structure was fabricated and the measured results are in good agreement with the simulated results. This novel design demonstrates superior low-pass filtering functionality and can easily be applied to monolithic circuits.     

Radiation from Electromagnetic Bandgap Microstrip Structures

The radiation from electromagnetic bandgap (EBG) microstrip structures is studied. The results show that the radiation from an EBG microstrip structure at most of the frequencies in the stopband and the passband is larger than that of the corresponding conventional microstrip line. Therefore, EBG microstrip circuit s should be shielded and new EBG microstrip structures whose radiation is little should be developed.     

Multi‐stack Technique for a Compact and Wideband EBG Structure in High‐Speed Multilayer Printed Circuit Boards

We propose a novel multi‐stack (MS) technique for a compact and wideband electromagnetic bandgap (EBG) structure in high‐speed multilayer printed circuit boards. The proposed MS technique efficiently converts planar EBG arrays into a vertical structure, thus substantially miniaturizing the EBG area and reducing the distance between the noise source and the victim. A dispersion method is presented to examine the effects of the MS technique on the stopband characteristics. Enhanced features of the proposed MS‐EBG structure were experimentally verified using test vehicles. It was experimentally demonstrated that the proposed MS‐EBG structure efficiently suppresses the power/ground noise over a wideband frequency range with a shorter port‐to‐port spacing than the unit‐cell length, thus overcoming a limitation of previous EBG structures.     

Wideband and compact bandstop filter structure using double-plane superposition

A novel bandstop filter (BSF) structure is proposed and measured for wideband and compact circuit applications. The proposed BSF realizes the wide stopband (2-octave) characteristics by superposing two different photonic bandgap (PBG) structures into a coupled double-plane configuration. Only three cells of the proposed structure are enough for the measured 10 dB stopband from 4.3 to 16.2 GHz. We expect this novel BSF structure is widely used for compact and wideband circuit applications, such as compact high-efficiency power amplifiers using harmonic tuning techniques.     

Coplanar Waveguide Bandpass Filters With Compact Size and Wide Spurious-Free Stopband Using Electromagnetic Bandgap Resonators

This work presents a novel coplanar waveguide (CPW) bandpass filter (BPF) that uses electromagnetic bandgap (EBG) resonators to reduce the size and suppress the harmonic responses. The propagation characteristic of the EBG structure is investigated by its associated equivalent circuit model. Compared with the conventional half-wavelength resonator at 5GHz, the EBG resonator is 60.5 % more compact. Based on the EBG CPW resonators, the inductively-coupled two-pole BPF with 3.8% 3-dB bandwidth and 2-dB insertion loss at 5GHz is implemented. This structure generates a 59.6% reduction in size and suppresses a second harmonic passband when compared with a conventional filter. To eliminate the third harmonic response, the proposed EBG CPW BPF further incorporates two EBG structures into its input and output ports and has the merit of a small circuit area     

A Power Plane With Wideband SSN Suppression Using a Multi-Via Electromagnetic Bandgap Structure

In this letter, a power plane with wideband simultaneous switching noise (SSN) suppression using a novel multi-via electromagnetic bandgap (EBG) structure is proposed. The -40dB stopband of the proposed EBG structure is about two to six times wider than the one-via structure, and the relative bandwidth is increased by about two times. It is implemented by only adding some vias between patches and the reference plane without changing any other geometrical parameters from one-via EBG structures. The excellent SSN suppression performance was verified by simulations and measurements     

A novel periodic electromagnetic bandgap structure for finite-widthconductor-backed coplanar waveguides

The one-dimensional (1-D) periodic electromagnetic bandgap (EBG) structure for the finite-width conductor-backed coplanar waveguide (FW-CBCPW) is proposed. Unlike the conventional EBG structures for the microstrip line and the coplanar waveguide (CPW), which are typically placed on one of the signal strips and the ground plane, this EBG cell is etched on both the signal strip and the upper ground plane of FW-CBCPW resulting in a novel circuit element. The equivalent circuit is also used to model the EBG cell. Measured and full-wave simulated results show that the cell exhibits remarkable stopband effect. The low-pass filter with lower cutoff frequency and wider rejection bandwidth is constructed from a serial connection of the EBG cells. The effect of back metallization on the guiding characteristic is also discussed. Compared to the published EBG cells, the proposed structure has the advantages of relative flexibility, higher compactness, lower radiation loss, and easier integration with the uniplanar circuits     

Design and Modeling of a Stopband-Enhanced EBG Structure Using Ground Surface Perturbation Lattice for Power/Ground Noise Suppression

Based on the ground surface perturbation concept, a novel stopband-enhanced electromagnetic-bandgap (EBG) structure has been proposed to suppress the power/ground noise on a three-layer package. This structure consists of a coplanar periodic pattern on the top layer, a ground plane on the third layer, and a ground surface perturbation lattice on the second layer with eight vias connecting to the ground plane. By designing the dimension and via numbers, the ground surface perturbation lattice can significantly enhance the stopband bandwidth. A generic 1-D circuit model is proposed for the three-layer EBG structure. The reason why the proposed structure can possess wider stopband will be explained. Several test samples are fabricated. The agreement of the stopband between the circuit model and measured results are good.      

一种新型紧凑宽带平面电磁带隙结构

针对一般谐振型电磁带隙结构相对带宽比较窄的特点,依据电磁带隙结构带隙形成机理和等效电路分析模型,该文提出了一种基于低介电常数低成本基底的紧凑宽带平面电磁带隙结构。实验结果表明,新结构具有54.1%的相对带宽,相比文献结构有超过100%的相对带宽改善,并且中心频率降低了25.2%,达到了实现紧凑宽带UC-EBG结构的目的。     

一种适用于同步开关噪声抑制的共面电磁带隙新结构

该文根据电磁带隙结构的带隙形成机理及共面电磁带隙结构等效电路分析模型,通过引入新型的C-型桥接连线及开槽设计,提出了一种适用于高速电路同步开关噪声(SSN)抑制的带有狭缝的共面C-型桥电磁带隙(CBS-EBG)结构。实测结果表明,在抑制深度为?40 dB时,阻带范围为296 MHz~15 GHz,与LBS-EBG结构相比,在保持高频段SSN抑制性能的同时,阻带下限截止频率由432 MHz下降至296 MHz,有效降低了带隙中心频率。研究了局部拓扑下的信号传输特性,结果表明,当采用局部拓扑并选择合适的走线策略时,该结构在保持良好的SSN抑制性能的同时,能够实现较好的信号完整性。     

Compact and wide stopband lowpass filter with novel comb CMRC

A novel comb compact microstrip resonant cell, entitled CCMRC, is firstly proposed. The compact configuration presents ultra wide stopband and attractive slow-wave characteristics. A lowpass filter, consisting of three CCMRCs connected in series, is designed and fabricated. The filter has the merits of low insertion loss in the passband, sharp, deep and wide rejection in the stopband and compact size. Good agreement between experimental and simulated results is achieved.     

Asymmetric Dual-Passband Coplanar Waveguide Filters Using Periodic Composite Right/Left-Handed and Quarter-Wavelength Stubs

A novel dual-passband coplanar waveguide (CPW) filter periodically loaded with the composite right/left-handed (CRLH) short-circuited stubs and the quarter-wavelength open-circuited stubs in asymmetric configuration is presented. The unit-cell equivalent circuit of the periodic structure in conjunction with Floquet's theorem is employed to find the propagation characteristics of passband and stopband regions. Unlike the conventional quarter-wavelength transmission-line inverter suitable only for a narrow frequency range, the dual-band inverter is adopted in the dual-passband filter to achieve a better frequency response within two operating bands. The performance of the 2.4/5.8-GHz third-order CRLH CPW dual-passband filter with 52% and 23% bandwidths is measured and validated by full-wave simulation. Two arbitrary passband regions are presented and the stopband within the passbands can be controlled by varying the length of open-circuited stub, supporting the flexibility and compactness of the proposed dual-passband filter     

Design of Novel Compact Electromagnetic Bandgap Structures with Enhanced Bandwidth

Two kinds of compact electromagnetic band gap （EBG） structures are designed. A two layer compact EBG structure configured with cross spiral shape line inductors and interdigital capacitors is first presented. Because of its significantly enlarged equivalent inductor and capacitance, the period of the lattice is approximately 4.5% of the free space wavelength. By insetting several narrow slits in the ground plane, the bandwidth of the main bandgap is enhanced by nearly 19%. Further effort has been made for designing a three layer compact EBG structure. Simulation results show that its period is reduced by about 26% compared to that of proposed two layer EBG structure, and the bandwidth of the main bandgap is about 3 times as that of the proposed two layer EBG structure. The detailed designs including a two layer compact 3×7 EBG array with and without defect ground plane and the three layer EBG array are given and simulation results are presented.     

一种新颖的S型宽阻带电磁带隙低通滤波器

提出了一种新颖的具有S型几何结构的小型宽阻带电磁带隙微带低通滤波器。通过把微带线弯绕成S型曲线形状,缩减了电磁带隙微带低通滤波器尺寸,而且同时获得了宽阻带。通过采用双面的几何结构,并采用补偿线和渐变加窗技术对地面缺陷进行调节,使所提出的低通滤波器获得了低插损,而且使阻带宽度进一步加宽。对所提出结构作了加工并进行了实物测量,测量结果表明,所设计滤波器的通带反射损耗的最大旁瓣幅度为-22 dB,阻带(S21<-20 dB)宽度为9.2 GHz,而其面积仅为36 mm×20 mm=720 mm2。     

Stopband Analysis Using Dispersion Diagram for Two-Dimensional Electromagnetic Bandgap Structures in Printed Circuit Boards

Electromagnetic bandgap (EBG) structures that provide an excellent isolation within the stopband are extremely effective in suppressing propagation of simultaneous switching noise on parallel power planes. However, a scattering parameter measurement and full-wave electromagnetic simulation for their entire structure are costly and time consuming. This letter presents a two-dimensional dispersion-diagram analysis based on a unit-cell network of EBG structures by extending a well-known dispersion-diagram analysis of one-dimensional infinite periodic structures. The approach is extremely effective in computing stopband frequencies and provides the stopbands with good agreement to the measured results     

Compact ultra-wideband bandpass filter using broadside coupled hairpin structures on multilayer liquid crystal polymer substrate

A novel ultra-wideband (UWB) bandpass filter (BPF) using a broadside- coupled hairpin structure and multilayer organic liquid crystal polymer (LCP) technology is presented. To suppress stopband harmonic response, folded stepped impedance structures were adopted as hairpin resonators in the design. The proposed filter has been investigated numerically and experimentally. Multilayer LCP technology was used to implement designed UWB BPF. Good agreement between simulated and measured results of the proposed filter was observed. They show that the fabricated UWB BPF has a good performance, including a small insertion loss, a flat group delay with a variation within 0.1 ns in most of its passband, a wide stopband from 11.0 20.0 GHz with a high rejection level up to 20.0 dB, and a very compact size of 9.8 x 7.5 mm (0.36 lg x 0.27lg, where lg is the guided wavelength of 50 V microstrip line at 6.85 GHz).     

Dual-band bandpass filter based on dual-plane microstrip/interdigital DGS slot structure

A novel dual-band bandpass filter based on a dual-plane structure consisting of both a microstrip and a defected ground structure (DGS) slot with an interdigital shape is proposed. The microstrip structure is connected to the ground plane by grounding vias to obtain tight coupling. By tuning the length of the fingers in the DGS, it is convenient to change the first passband operating frequency. The equivalent-circuit model is derived for the filter. A filter with two passbands centring at 2.44 and 3.28 GHz is shown with stopband attenuation of greater than 30 dB over the frequency range 3.7- 9 GHz.     

A design of the novel coupled-line bandpass filter using defectedground structure with wide stopband performance

In this paper, a novel three-pole coupled-line bandpass filter with a microstrip configuration is presented. Presented bandpass filters use defected ground structure (DGS) sections to simultaneously realize a resonator and an inverter. The proposed coupled-line bandpass filter provides compact size with low insertion-loss characteristic. Furthermore, a DGS shape for a microstrip line is newly proposed. The proposed DGS unit structure has a resonance characteristic in some frequency band. The proposed coupled-line filter can provide attenuation poles for wide stopband characteristic due to resonance characteristic of DGS. The equivalent circuit for the proposed DGS unit section is described. The equivalent-circuit parameters for DGS are extracted by using a three-dimensional finite-element-method calculation and simple circuit analysis method. A design method for the proposed coupled-line filter is derived based on coupled-line filter theory and the equivalent circuit of the DGS. The experimental results show excellent agreements with theoretical simulation results     

A novel power plane with super-wideband elimination of ground bounce noise on high speed circuits

A novel L-bridged electromagnetic bandgap (EBG) power/ground planes is proposed with super-wideband suppression of the ground bounce noise (GBN) from 600Mz to 4.6GHz. The L-shaped bridge design on the EBG power plane not only broadens the stopband bandwidth, but also can increase the mutual coupling between the adjacent EBG cells by significantly decreasing the gap between the cells. It is found the small gap design can prevent from the severe degradation of the signal quality for the high-speed signal referring to the perforated EBG power plane. The excellent GBN suppression performance with keeping reasonably good signal integrity for the proposed structure is validated both experimentally and numerically. Good agreement is seen.     

Compact Structure With Three Attenuation Poles for Improving Stopband Characteristics

A novel compact structure with three controllable finite attenuation poles at stopband is presented. The new structure is composed of a pair of symmetrical parallel coupled-lines and a capacitive load. With this configuration, three finite attenuation poles are available, which can improve the stopband characteristics of low-pass filters (LPFs) or the upper stopband performances of band-pass filters. The research method is based on a transmission-line model for tuning the finite attenuation poles. In order to examine the feasibility of the proposed structure, a new type of LPF with broad stopband and sharp cutoff frequency response is designed, fabricated, and measured. The experimental results of the fabricated circuit agree well with the simulation and analytical ones