基于复合左右手传输线的2.45 GHz微带天线设计

基于复合左右手传输线基本原理, 提出了电磁带隙结构的双负媒质微带天线设计方法, 并制作了2.45 GHz的微带天线.该微带天线由2个单元的电磁带隙组成, 此电磁带隙结构经过优化采用非均匀结构, 可通过调整贴片尺寸和金属过孔半径来改变电磁带隙结构单元等效电路的并联部分电容和电感, 进而调节天线的谐振频率.设计并制作的微带天线其贴片整体尺寸为53.2 mm×19.8 mm, 在2.45 GHz的回波损耗为-32.6 dB, 方向图近似为8字形方向图, 最大增益为0.72 dB.仿真和测试的回波损耗、方向图符合得很好, 从而验证了这种设计方法的有效性.     

EBG结构磁性材料微带天线的研究与设计

以磁性材料(JV-5)作为基板,设计双L型结构的微带天线,带宽是普通基板的2倍以上,尺寸缩小了40%。在此基础上引入电磁带隙(EBG)结构,设计了一种基于磁性基板EBG结构的微带天线,该EBG结构采用接地板腐蚀性,即在地板上腐蚀出周期H型和圆形结构,采用电磁仿真软件HFSS14.0进行仿真设计。结果显示,与非磁性材料做基板的微带天线相比,EBG结构磁性材料具有小型化和宽频化突出优点,相对带宽达到10%以上,增益方面略有降低,引入EBG结构后能在一定程度上减小了天线的尺寸同时增大了天线的带宽,改善了天线的增益和辐射特性。     

不同电磁带隙结构对微带天线性能的影响

EBG（电磁带隙）结构已在微带贴片天线中得到广泛的应用。本文采用EBG结构对传统贴片天线进行了改进。使用基于有限元法（FEM）的软件模拟并比较了不同EBG结构对贴片天线性能的影响。结果表明基于基底打孔型方形孔EBG结构的贴片天线的性能最佳,其增益、带宽和输入回波损耗都得到了较大的改善。     

Microstrip Patch Antennas on Tunable Electromagnetic Band-Gap Substrates

A tunable metamaterial in integrated circuit structures is investigated through an example of a microstrip patch antenna on a mushroom-type electromagnetic band-gap (EBG) structure. The patch antenna is designed as a half-wavelength resonator of an EBG loaded microstrip transmission line. The operating frequency of a patch antenna can be switched and controlled dynamically by loading diode switches in between vias and the ground plane. When the switches are on, the EBG surface is short to the ground and is at its on-state; while when the switches are turned off, the EBG surface is dc open and is at its off-state. It is found that the resulting patch antenna in-band resonant frequencies are very different at these two states. Antenna dual-band frequencies, gain, efficiency, and radiation patterns are characterized. The designed switchable EBG-patch antenna is fabricated and tested in these two states. The measurement is found in good agreement with simulation. An example is also given for the case of selected switches within the EBG elements to tune dynamically the resonant frequency.      

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     

EBG 结构中引入单元尺寸渐变对带隙展宽的作用

针对EBG 结构带隙带宽较窄这一问题,提出一种新的实现方法——单元尺寸线性渐变方法,在不增大结构尺寸的条件下实现了更宽的带隙。文中以微带EBG 和Mushroom-like EBG 两种结构为例进行分析计算,仿真结果表明单元尺寸渐变可以使这两种EBG 结构的带隙带宽增加30%~40%,为拓展EBG 结构的带隙带宽提供了一种新的途径。     

二维电磁带隙结构研究的新方法

应用悬置微带线方法(SMM)对二维EBG结构进行了测量和计算。对二维电小EBG(UC—EBG和PV—EBG)的特性用SMM法进行了统一的实验和仿真分析。与其他方法对比，由于采用了“强耦合”结构，更能显现出二维电磁带隙结构的特性。同时提出了新型的悬置微带贴片的EBG天线，该天线结构紧凑，更利于EBG的实际应用。     

蘑菇型EBG微带天线电磁辐射特性分析

利用矩量法对探针馈电的蘑菇型EBG微带天线的电磁辐射特性进行了分析。首先建立了天线模型,采用细导线的带模型将馈电探针和EBG短路过孔等效为细带,并与EBG金属表面和微带贴片一样均采用平面三角面元剖分,RWG基函数作为电流展开函数,将线面连接问题转化为面面连接问题。然后给出了采用空域矩量法对天线辐射特性进行分析的全过程,并介绍了激励源的添加模型。最后对蘑菇型EBG微带天线的回路损耗、输入阻抗和方向图等特性进行了分析计算,相关结果与FEKO和文献吻合良好,验证了本文方法的正确性。     

Design and implementation of electromagnetic band‐gap embedded antenna for vehicle‐to‐everything communications in vehicular systems

We proposed a novel electromagnetic band‐gap (EBG) cell‐embedded antenna structure for reducing the interference that radiates at the antenna edge in wireless access in vehicular environment (WAVE) communication systems for vehicle‐to‐everything communications. To suppress the radiation of surface waves from the ground plane and vehicle, EBG cells were inserted between micropatch arrays. A simulation was also performed to determine the optimum EBG cell structure located above the ground plane in a conformal linear microstrip patch array antenna. The characteristics such as return loss, peak gain, and radiation patterns obtained using the fabricated EBG cell‐embedded antenna were superior to those obtained without the EBG cells. A return loss of 35.14 dB, peak gain of 10.15 dBi at 80°, and improvement of 2.037 dB max at the field of view in the radiation beam patterns were obtained using the proposed WAVE antenna.     

A New CMOS Multilayer Electromagnetic Band-Gap Microstrip Line and Experimental Investigation of UWB Pulse Propagation

We report on the development of a new microstrip line and Its experimental results on ultra-wideband pulse propagation. The transmission line employs electromagnetic band-gap (EBG) structures and is implemented in the multilayer metal stack of a 0.25-mum CMOS process. The inductance and capacitance per unit length of the new microstrip line can be independently adjusted to achieve various slow-wave factors for different characteristic impedances by properly selecting the dimensions of the EBG cells, their respective locations, and the CMOS metal layers. Experimental time-domain investigation of the pulse propagation reveals an interesting phenomenon of pulse compression. This unique property of the new CMOS multilayer EBG microstrip line can be exploited to help generate pico-second pulse as well as to compensate for the loss and dispersion of transmission lines, hence effectively retaining or enhancing the pulse propagation characteristics in UWB impulse circuits.     

A modified contour Integral analysis for Sierpinski fractal carpet antennas with and without electromagnetic band gap ground plane

A modified contour integral method coupled with segmentation method has been used, for the first time, to analyze both the Sierpinski fractal carpet (SFC) antennas of different orders and an SFC antenna with electromagnetic band gap (EBG) ground plane. The close agreement between the calculated and measured results for resonant frequencies and input return losses indicates that this technique can be used to accurately predict the impedance characteristic. A novel stacked microstrip Sierpinski carpet fractal antenna using the EBG ground plane is also presented. Comparing to an ordinary microstrip fractal antenna, which has a maximum bandwidth of approximately 2%, the proposed antenna has a higher input impedance bandwidth of nearly 9%. The radiation patterns of the proposed antenna are improved due to the removal of unwanted radiation caused by the surface wave. The experimental measurement results of the proposed antenna are presented in this paper.     

Microwave Bandstop Filters Using Novel Artificial Periodic Substrate Electromagnetic Band Gap Structures

Novel microwave and millimeterwave (mm-wave) bandstop filters using artificial periodic substrate electromagnetic bandgap (EBG) are investigated in this paper. Three types of microstrip structures using periodically modified trace width, patterned dielectric substrate, and periodically modified ground plane are treated, respectively. By periodically modifying either the width of the conductor trace, the substrate height, or the dielectric constant of a standard microstrip transmission line, it has been possible to design microwave bandstop filter functions with wide stopband characteristics and reduced size, compared to conventional microwave/RF filter structures. Commercial electronic design automation (EDA) and computational electromagnetic tools such as Agilent's advanced design system (ADS) and CST Microwave Studio are used in the design and simulations of these filter structures. The effects of the physical parameters of the structures on the filter characteristic are studied. The design procedure and simulation results are described and possible applications of these filter structures are discussed in this paper. A particularly wide stopband is achieved by the circuits presented in this paper, which use only a few cell elements. A significant performance improvement of microstrip patch antenna has been observed by implementing one of the presented EBG periodic substrate structures.      

EBG结构在曲面共形天线中的应用

利用Mushroom型EBG结构的等效电路和Bragg反射条件,设计了三种曲面EBG结构。并通过刻蚀和加载的办法将它们应用在曲面共形天线中。经过建模仿真,并且与普通的天线进行比较,发现附加EBG结构的共形天线的回波损耗得到了很好的抑制,辐射方向图也取得了很好的改良。天线的前向辐射有了不同程度的提高,背向和侧向辐射减小,在附虽EBG结构的二元阵中,阵元间的耦合效应也得到了有效的抑制。不过EBG结构单元不能距离天线贴片过近,否则也会引起新的互耦。     

曲面EBG结构带隙特性的研究

利用光学B ragg反射条件,设计了一种曲面电磁带隙结构。采用悬置微带线法,分析了其结构参数以及圆柱结构参数对带隙特性的影响。结果表明,结构参数对表面波带隙影响的规律与平面上一致,圆柱曲率对表面波带隙的影响不是太大,只是带隙中心频率略有下降。这一结论对在曲面共形天线上应用电磁带隙结构提高天线性能有重要的指导意义。     

A Novel Compact Spiral Electromagnetic Band-Gap (EBG) Structure

A novel compact electromagnetic band-gap (EBG) structure in a spiral shape is presented and investigated. This structure significantly enlarges the capacitance between neighboring elements. The simulations and experimental results have proved that the size of the spiral structure is only 30.9% of the conventional EBG structure. Two applications have been shown, including patch antenna with the spiral EBG structure and a double-element microstrip antenna array with low mutual coupling. The measured results show that a gain improvement over 3 dB and a significant reduction of cross polarization in H-plane are obtained. A 6 dB reduction of mutual coupling is achieved in a double-element EBG microstrip antenna array.     

基于蘑菇状谐振器的谐波抑制的微带贴片天线

提出了一种基于耦合谐振器的微带贴片天线谐波抑制的方法。通过在微带天线馈线与地板之间增加蘑菇状电磁带隙（EBG）单元的谐振器,有效地抑制了天线的2次和3次谐波,减少了谐波辐射对周围微波器件的干扰。对天线的等效电路模型进行了详细分析和研究,通过改变参数令谐振器工作在天线的谐波频率上,从而抑制天线的谐波辐射。为了对理论分析进行验证,我们加工了实物模型并进行测试,测试的数据显示微带天线的2次谐波减少了11.6dB,3次谐波减少了8.4dB。     

Tapered dual-plane compact electromagnetic bandgap microstrip filter structures

In this paper, the designs of two novel tapered dual-plane compact electromagnetic bandgap (C-EBG) microstrip filter structures are presented. With the dual-plane configuration, the proposed structure displays an ultrawide stopband with high attenuation within a small circuit area. Chebyshev distribution is adopted to eliminate ripples in the passband caused by the periodicity of the EBG structure. This gives rise to a compact EBG structure that exhibits excellent transmission and rejection characteristics in the passband and the stopband, respectively. The proposed structures are implemented and the measurement results are found to be in good agreement with the simulation results, verifying the excellent stopband and passband performance obtained using the proposed configuration. These novel structures are easy to fabricate and are promising structures that have wide applications for compact and high performance circuit component designs in microwave circuits.     

Novel Planar Electromagnetic Bandgap Structures for Mitigation of Switching Noise and EMI Reduction in High-Speed Circuits

Planar electromagnetic bandgap (EBG) structures with novel meandered lines and super cell configuration are proposed for mitigating simultaneous switching noise propagation in high-speed printed circuit boards. An ultrawide bandgap extending from 250 MHz to 12 GHz and beyond is demonstrated by both simulation and measurement, and a good agreement is observed. These perforated EBG-based power planes may cause spurious and unwanted radiation. In this paper, leakage radiation through these imperfect planes is carefully investigated. It is found that the leakage field from these planar EBG structures is highly concentrated around the feed point, and the field intensity is attenuated dramatically when passing across several periods of patches. A novel concept of using these EBG structures for electromagnetic interference reduction is also introduced. Finally, the impact of power plane with EBG-patterned structures on signal integrity is studied.     

Design and Development of an Efficient EBG Structures Based Band Notched UWB Circular Monopole Antenna

Band notched circular monopole antennas for ultra-wide band applications are proposed in this paper. The proposed antennas in this paper can reject worldwide interoperability for microwave access WiMAX band (3.3–3.8 GHz) and wireless local area network WLAN band (5–6 GHz). Antennas utilises mushroom-type electromagnetic band gap (EBG) structures and I-slot embedded edge located via (ELV) EBG structures to achieve band-notched designs. The advantages of band notched designs using EBG structures like notch-frequency tuning, dual-notch antenna designs and stable radiation pattern are also verified. Various antenna designs with slot in EBG structures, variations in placement of EBG structures, number of EBG structures and ELV type EBG structures are simulated. About 30% reduction in size of EBG structures is obtained if conventional mushroom type EBG is replaced by proposed I-slot embedded ELV-EBG structure. Fabricated and measured results are in good agreement with simulated ones.

     

Wideband Dipoles on Electromagnetic Bandgap Ground Planes

The performance of broadband dipole antennas above electromagnetic bandgap (EBG) structures is investigated. Two different structures are examined. One is a diamond dipole over an EBG with square patch elements optimized by hand and the other an open sleeve dipole over an EBG optimized by a genetic algorithm (GA). Both configurations demonstrate that a low profile dipole antenna over an EBG can have a broad bandwidth. Careful design of both is required and in particular for best results, the antenna-EBG system should be optimized together, rather than as separate components. The performance is compared to an absorber backed wideband dipole antenna and it is found that the gain is significantly increased, whilst the bandwidth is reduced. In general, for the diamond dipole antenna return loss bandwidths of over 2:1 (67%) have been achieved, although radiation pattern control is difficult and reduces the bandwidth to the order of 1.4:1 (33%). The sleeve dipole over an EBG achieved a bandwidth of 1.28:1 (26%). The realized gain, which is power gain reduced by input match loss, of both structures are approximately the same. GA optimization and parametric studies seem to suggest that bandwidths significantly greater than these are difficult to achieve.