使用非均匀特异媒质覆层的高增益谐振腔天线

采用非均匀特异媒质覆层,设计了一种具有高增益特性的新型谐振腔天线。该谐振腔天线采用矩形微带贴片天线作为辐射单元,安装在金属谐振腔内,其谐振频率为10 GHz。为提高天线增益,将腔表面安装蚀刻在微带基板上,由周期性单元组成特异媒质覆层。迥异于常规的单元尺寸均匀一致特异媒质覆层,本文研制的非均匀特异媒质覆层包含9×9个矩形单元,单元大小渐变。仿真表明,与常规均匀特异媒质覆层相比,该新颖的非均匀特异媒质覆层相当大程度提升了天线定向辐射性能：天线增益提高1.2 dB(从20.3 dBi增加到21.5 dBi),天线的旁瓣得到了抑制,主旁瓣比下降5 dB;同时,天线谐振频率和阻抗带宽等其他性能基本保持不变。     

Metamaterial Superstrate and Electromagnetic Band-Gap Substrate for High Directive Antenna

A high directive planar antenna made from a metamaterial superstrate and an electromagnetic band-gap (EBG) substrate has been investigated. A patch antenna surrounded with EBG structures is used as the radiation source. The CST Microwave Studio is used for the simulation. The results show that the gain of the antenna with metamaterial is 21.6 dB at the operating frequency of 14.6 GHz. Compared with the patch feed with the same aperture size but without the metamaterial superstrate, the performance of the antenna is improved obviously and the gain increases about 12.4 dB.     

Performance enhancement of rectangular microstrip patch antenna using double H shaped metamaterial

In this paper a high performance rectangular microstrip patch antenna (RMPA) has been designed using doubleHshaped metamaterial. First, the doubleHshaped metamaterial has been designed and optimized at 5.2 GHz resonant frequency of patch antenna. It has been found that embedding of this metamaterial into the substrate beneath the reference patch antenna improves its return loss and bandwidth without changing the resonant frequency and gain. To further enhance the gain and efficiency of the metamaterial embedded RMPA a superstrate of double H shaped metamaterial has been applied at the distance of -/3 over it. Finally, a high gain, broadband and good impedance matched metamaterial inspired RMPA has been obtained. The proposed antenna was simulated and optimized using HFSS software. The prototype antenna has been fabricated and measured results of the proposed antenna are found to be in good agreement with the simulated results.     

Dual band microstrip patch antenna array loaded with split ring resonators and via holes

Reduction in antenna size by using multi-band radiators play a vital role in the miniaturization of present world wireless handheld devices, as dual band behaviour of the antennas result in the integration of more than one communication standard in a single system and thus, saving the installation space required for separate antennas. In this context, this communication presents a shorted-pin dual band metamaterial inspired microstrip patch antenna array. Under the unloaded conditions, the traditional patch antenna array resonates at 5.8 GHz with gain of 9.8 dBi and bandwidth of 540 MHz. However, when each patch of this traditional antenna array is loaded with split ring resonator (SRR) and a metallic via hole is introduced in the patch, the same antenna array produces an additional resonant frequency in IEEE 802.11b/g/n 2.45 GHz Wi-Fi band with bandwidth and gain of 290 MHz and 5.6 dBi, respectively, while the initial resonant frequency (i.e. 5.8 GHz) gets shifted to IEEE 802.11ac 5 GHz Wi-Fi band, providing the gain and bandwidth of 11.4 dBi and 510 MHz, respectively. The proposed antenna array has been fabricated, and the measured results are presented to validate the proposed array. Moreover, the equivalent circuit of the proposed antenna array has been designed and analyzed to validate the simulated, measured and theoretical results. Attainment of dual band characteristics by incorporating the metamaterial with single band traditional patch antenna array makes this structure novel, as this has been achieved without any extra hardware cost, size and loss of structural planarity. Also, both the frequency bands of this proposed metamaterial inspired antenna array possess considerable gain and bandwidth.     

An analysis of RCS for dual-band slotted patch antenna with a thin dielectric using shorted stubs metamaterial absorber

A dual-band slotted patch antenna with thin dielectric has been proposed for Ku–band applications. A rectangular patch with pair of bent slots at each side of center has been designed and resonant at 11.95 GHz and 14.25 GHz with respect to ITU standard. A dual resonance ultrathin metamaterial absorber (MMA) based on circular rings and shorted stubs operating at same frequency bands have been designed. Its behavior at an oblique angle of incidence and polarization sensitivity has been also observed. In this research work, it has been obtained that when dual–band slotted patch antenna is surrounded by proposed MMA structure, it significantly enhances in-band stealth capability of the antenna. The monostatic and bistatic RCS of the proposed design has been reduced significantly whilst maintaining and preserving the antenna radiation performance. This design finds its application in satellite and wireless communication.     

Analysis of Antenna Gain Enhancement with a New Planar Metamaterial Superstrate: an Effective Medium and a Fabry-Pérot Resonance Approach

We have compared gain enhancement behavior of patch and horn antennas from two different points of view: namely, effective medium analysis and a Fabry-Pérot cavity resonance approach. To examine how a near-zero refractive index (n) affects the performance of antennas, we designed a new planar metamaterial (MTM) superstrate, which can produce negative, zero, and positive values of n at around 2 GHz. We placed the MTM superstrate very close to the patch and horn antennas to see whether an n value that is effectively near zero can collimate antenna beams and increase antenna gain, which provided opposite gain behavior for the two antennas. To explain the dissimilar enhancement in the gain of the patch and horn antennas, we retrieved constitutive parameters from the proposed MTM superstrate and discussed the effect of various incidence angles upon the superstrate. In addition, to increase the gain further, we examined appropriate resonant heights between the antennas and the superstrate. Consequently, with the help of Fabry-Pérot cavity resonance, we obtained relatively high antenna gain. Moreover, the results of the prediction are in good agreement with the results of the measurement.     

Miniaturization of microstrip loop antenna for wireless applications based on metamaterial metasurface

The metamaterial and fractal techniques are two main methods for antenna miniaturization and in this paper, we have modeled an especial shape of the antenna based on loop formation with metamaterial load for this aim. The metamaterial layer is made by multi parallel rings and the result shows that the final antenna size reduced drastically while the frequency shifts from 7 to 4 GHz. The antenna has Omni-directional pattern with the gain of 3.5 dBi, so the size is reduced around 40%for 4.5 GHz and another resonance is made at 2.5 GHz with a return lossless than −6 dB with more than 60% frequency shift. The reflection and transmission have been utilized for showing the left hand characteristic based on two port periodic simulations in HFSS full wave software. We show that how the metamaterial load can provide the circular polarization (CP) by controlling the current distribution. We also presented that by making slots we obtained the better Axial Ratio (AR) and miniaturized the antenna with reconfigurable qualification. As a result of fact, we show that by using metasurface we able to miniaturized the antenna and simultaneously achieved the circular polarization.     

基于零折射超材料的双频高增益微带天线*

基于双面对称单环开口谐振器对结构奇异的电磁特性,设计了一种频率可控的各向异性零折射超材料。将这种零折射超材料应用于普通双频微带天线,制备了中心频率为5. 15GHz 和6. 8GHz 的零折射双频微带天线。仿真和测试结果显示,由于零折射超材料的引入,天线的侧向辐射减弱,方向性增强。在低频工作时,零折射微带天线E 面和H 面半功率波束宽度分别减小了29°和10°,增益提高了2. 2 dB。在高频工作时,零折射微带天线E面和H 面半功率波束宽度均减小了16毅,增益提高了2. 4 dB。将零折射超材料应用于微带天线的介质基板,为高性能双频微带天线设计提供了有效途径。     

Enhanced‐Gain Planar Substrate‐Integrated Waveguide Cavity‐Backed Slot Antenna with Rectangular Slot Window on Superstrate

A novel substrate‐integrated waveguide (SIW) cavity‐backed slot antenna is proposed in this study to achieve enhanced‐gain performance. The peak gain is remarkably improved with the use of an SIW cavity and metallic superstrate. The superstrate comprises a single rectangular slot window and two half‐wavelength patches. The gain can be enhanced by combining the in‐phase radiating fields. Further, the 10 dB bandwidth of the proposed antenna ranges from 2.32 GHz to 2.49 GHz, which covers the wireless local area network band. The measured peak gain is 9.44 dBi at 2.42 GHz.     

Dual band rectangular patch antenna array with defected ground structure for ITS application

A dual band inset fed rectangular patch antenna array has been proposed for intelligent transportation system (ITS) application. This paper proposes 8–element patch array antenna with defected ground structure (DGS). The simulated results of 2, 4 and 8 element patch with and without DGS are also compared. Proposed antenna gets dual band of 5.02 GHz and 5.92 GHz centre frequency with DGS. The 8–element patch array antenna with DGS is fabricated and its result is compared with simulation result. 26.5 dBi and 24.9 dBi is measured gain of the proposed antenna structure for 5.02 GHz and 5.92 GHz centre frequency respectively.     

Wideband to narrowband/dual band characteristics of monopole antenna using frequency selective surfaces

A monopole antenna having desirable transmission characteristics with high gain is proposed. The monopole antenna comprises 45° tilted square shaped patch and modified rectangular metallic ground plane on FR4 dielectric substrate. The proposed monopole antenna operates from 2.6 GHz to 9.7 GHz with maximum peak gain of 2.3 dBi. Now, a dual-layer aperture-type FSS is designed having a passband from 5.9 GHz to 9.2 GHz and incorporated with the proposed monopole antenna. Thus, the combination only covers the selective frequency band from 5.5 GHz to 8.7 GHz with a stable gain of around 5 dBi. Second, another FSS is designed, which has one stop-band from 4.1 GHz to 5.4 GHz and two passbands on the both sides of this stop-band. This combination does not work from 4.1 GHz to 5.5 GHz but covers dual band from 2.48 GHz to 3.3 GHz with a peak gain of 5 dBi and 5.5 GHz to 10 GHz with a peak gain of 5.5 dBi. Therefore, without modifying the antenna design, any tunable transmission band can be achieved by the proposed combination. The proposed antenna and FSS combination structure may be suitable for military wireless applications for its band selection characteristics.     

A High‐Gain Microstrip Patch Array Antenna Using a Superstrate Layer

A dielectric superstrate layer above a microstrip patch antenna has remarkable effects on its gain and resonant characteristics. This paper experimentally investigates the effect of a superstrate layer for high gain on microstrip patch antennas. We measured the gain of antennas with and without a superstrate and found that the gain of a single patch with a superstrate was enhanced by about 4 dBi over the one without a superstrate at 12 GHz. The impedance bandwidths of a single patch with and without a superstrate for VSWR < 2 were above 11%. The designed 2×8 array antenna using a superstrate had a high gain of over 22.5 dB and a wide impedance bandwidth of over 17%.     

Performances of OSIC Detector of an UpLink OFDM Massive-MIMO System in Rayleigh and Ricain Fading Channels

A compact rectangular microstrip-fed Ultra Wideband patch antenna with double band notched feature at Wi-Max and WLAN is offered in this paper. The designed antenna is composed of an ordinary rectangular patch antenna with a partially defective ground structure. For achieving dual notch characteristics a ‘U’ and ‘Reversed U’ slots are embedded in the radiating patch. The partial ground plane structure with U shaped slot in the middle is incorporated for achieving additional resonance and bandwidth enhancement. The proposed antenna has a measurement of 20 × 33 × 1.6 mm³. First notch created by U shaped slot at frequency 3.5 GHz is for Wi-Max (from 2.9 to 4.5 GHz) and Second notch which is generated by Reversed U shaped slots at frequency 5.4 GHz is for WLAN (from 5.49 to 6.45 GHz). The antenna covers almost complete range of Ultra Wideband (3.1–10.6 GHz). The Simulation analysis of the proposed antenna is carried out using CST-2011 simulation software. The radiation pattern of the simulated antenna is near Omnidirectional and the Gain of proposed antenna is almost stable over the range of UWB excluding notch bands.

     

具有谐波抑制功能的双极化缝隙天线

针对微波能量传输领域中接收天线与发射天线发生极化失配时,整流天线接收的能量会急剧下降的问题,设计了一款工作在2.45 GHz具有谐波抑制功能的双极化缝隙接收天线,该接收天线本身发生一定角度旋转时仍可通过双极化的特性接收能量。通过在贴片上开大小合适、结构对称的缝隙,实现天线水平极化和垂直极化;运用缺陷地结构,实现谐波抑制功能。仿真结果显示,在2.45 GHz处,天线的隔离度高于17.6 dB,增益3.9 dBi,阻抗匹配良好,在二次、三次谐波处天线的回波损耗为-0.38 dB和-0.96 dB,仿真结果和实测基本吻合。     

A Dual Polarized Triple Band Stacked Elliptical Microstrip Patch Antenna for WLAN Applications

In this paper, a single coaxial feed dual polarized triple band stacked microstrip patch antenna for wireless applications is presented. The proposed stacked antenna has two resonating elements with lower layer consisting of a truncated corner square patch and upper layer with an elliptical patch. Both the layers of proposed antenna are printed on RT Duroid^® 5880 substrate (having ?_r?=?2.2). The antenna shows triple band resonance at 4.2, 4.8 and 5.8 GHz with circular polarization behaviour at the first two resonances and linear polarization characteristic in the third resonance respectively. The typical realized gain of proposed antenna is around 7 dB in all three resonating bands.     

A Quad Band Metamaterial Miniaturized Antenna for Wireless Applications with Gain Enhancement

This paper presents a designing of dual-coated miniaturized metamaterial inspired quad band antenna for wireless standards with gain enhancement. Proposed design has compactness in size with electrical dimension of 0.239?×?0.351?×?0.0127 λ (30?×?44?×?1.6 mm³), at lower frequency of 2.39 GHz. The antenna consist a double printed slotted hexagonal shape radiating section with implementation of metamaterial rectangular split ring resonator. Antenna achieve quad bands for wireless standards WLAN (2.4/5.8 GHz), WiMAX (3.5 GHz), IEEE 802.11P (WAVE-5.9 GHz), ITU assigned X bands (7.25–7.75, 7.9–8.4 GHz) and satellite communication systems operating bands (C-band: 7.4–8.9 GHz and X-band: 8–10 GHz for satellite TV). An acceptable gain, stable radiation characteristics and good impedance matching are observed at all the resonant frequencies of the proposed structure. By application of proposed frequency selective surface an average enhancement of gain is about 4–5 dB over the operating band. Antenna fabricated and tested represent good agreement between the simulated and measured results.

     

A quad-polarization and frequency reconfigurable square ring slot loaded microstrip patch antenna for WLAN applications

In this paper, a novel polarization and frequency reconfigurable microstrip patch antenna which can switch between vertical and horizontal linear polarizations, left hand and right hand circular polarizations at two WLAN frequencies is presented. The orthogonal linear polarizations are achieved by a square microstrip patch antenna fed by two ports on adjacent sides. By introducing corner truncated perturbation on opposite corners of right diagonal of a square patch, orthogonal circular polarizations are achieved. By controlling the bias voltage of two PIN diodes loaded at perturbed corners, a single structure can achieve quad polarization states. Furthermore, by superimposing a square ring slot into the corner truncated square patch and incorporating four PIN diodes into the square ring slot, quad polarization are achieved at dual frequencies. Simulated and measured results indicate that the antenna can achieve quad polarization at two WLAN bands (5.15–5.35 GHz) and (5.75–5.85 GHz). The proposed antenna is simple, has low profile and can be scaled easily for other frequencies.     

Asymmetrical mirror imaged monopole antenna with modified ground structure for DBDP radiations

ABSTRACT

In this article, asymmetrical mirror-imaged monopole antenna comprises a rectangular patch with tuneable stub and supported with modified ground structure (MGS) is investigated. The proposed antenna is characterised for dual band dual polarised (DBDP) radiations and can operate at 2.45 GHz for Wi-Fi and WLAN systems (2.4–2.485 GHz) and 5.45 GHz for WLAN band (WLAN band: 5.2–5.8 GHz) with the corresponding polarisations. A rectangular patch integrated with tuneable stub and a pair of asymmetrical inverted L-shaped slots positioned at ground plane is responsible for circularly polarised higher band; while a parasitic patch is created due to slotting of a mirror-imaged stub from the extended ground plane which is accountable for lower frequency band. The fabricated prototype shows that the measured Impedance bandwidths (VSWR < 2) are 350 and 1770 MHz for lower and higher frequency bands, respectively. The measured axial ratio bandwidth (AR < 3 dB) is yielded as 1450 MHz centred at 5.44 GHz for higher frequency band. The peak gains are measured as 4.3 and 4.15 dB for lower and higher frequency band, respectively. For the prototype antenna, substantial 3-dB beamwidth is found along with good cross polarisation suppression.     

Improvement of the Performance Characteristic of UWB Antenna Using a Novel Double-Layer FSSs Operating at the Ku-Band

This paper proposed a novel compact design of UWB antenna. Our design used an uni-planar EBG double-layer of FSSs to enhance performance characteristics of UWB antenna in operation frequency of 14 GHz/Ku Band. This UWB antenna occupies a compact size of 40.36?×?29.36 mm² with space/gap between the radiator patch and double-layer of FSSs is 10 mm. We used a simple rectangular truncated-corner as a radiating patch. Double-layer of FSSs consist of a lower layer of FSS that used a unit cell of rectangular loop and an upper layer of FSS applied a wire grid. Optimized size of the truncated-corner is 2?×?0.5 mm², optimal space/gap between radiator patch and double-layer of FSSs is 10 mm, and the width of a rectangular loop in the lower layer of FSS is 1.742 mm. Our proposed uni-planar EBG double-layer of FSSs based UWB antenna reaches S11 parameter of ?42.381, a ?10 dB impedance bandwidth of 1.941 GHz (12.964–14.905 GHz), and a VSWR of 1.0154 in operation frequency 14 GHz. In addition, our UWB antenna design has a high gain about 6.1 dB. Applying of uni-planar EBG double-layer of FSSs improve significantly the performance characteristic of UWB antenna.