Metamaterial‐inspired miniaturized antenna loaded with IDC and meander line inductor using partial ground plane

In this article, a novel omnidirectional compact dual band metamaterial‐inspired antenna with CPW feed has been proposed for application of GSM 1800 (1.71‐1.785 GHz/1.805‐1.879 GHz), GSM 1900 (1.85‐1.91 GHz/1.93‐1.99 GHz), UMTS (1.92‐2.17 GHz), WLAN/Wi Fi (4.9, 5, 5.9 GHz), HiperLAN1 (5.15‐5.3 GHz), and HiperLAN2 (5.47‐5.72 GHz) using a combination of meander line inductor and interdigital capacitor (IDC). The antenna consists of complimentary right/left handed (CRLH) transmission line on both sides of patch to excite zeroth order mode (n = 0). The rectangular slotted stubs act as a virtual ground for the structure using a short circuit condition at the end of the IDC. The zeroth order resonance (ZOR) frequency is mainly controlled by IDC and partially with the meander line inductor. The designed antenna operates from 1.72 to 2.22 GHz and 4.25 to 5.88 GHz with radiating size of 0.56λ_o × 0.35λ_o (32 × 20 mm²), where λ_o is the free‐space wavelength at ZOR frequency of 5.27 GHz. The proposed antenna offers measured impedance bandwidth (|S₁₁| <?10 dB) of 25.3 and 18.7% at 1.95 and 5.28 GHz and covers the targeted frequency bands. The proposed structure offers omnidirectional radiation patterns are congruous throughout the working band.     

A compact dual‐band zeroth‐order resonator antenna loaded with meander line inductor

A novel zeroth‐order resonator (ZOR) meta‐material (MTM) antenna with dual‐band is suggested using compound right/left handed transmission line as MTM. In this article, suggested antenna consists of patch through series gap, two meander line inductors, and two circular stubs. The MTM antenna is compact in size which shows dual‐band properties with first band centered at 2.47 GHz (2.05‐2.89 GHz) and second band is centered at 5.9 GHz (3.70‐8.10 GHz) with impedance bandwidth of (S₁₁ < ? 10 dB) 34.69% and 72.45%, respectively. At ZOR mode (2.35 GHz), the suggested antenna has overall dimension of 0.197λ_o × 0.07λ_o × 0.011λ_o with gain of 1.65 dB for ZOR band and 3.35 dB for first positive order resonator band which covers the applications like Bluetooth (2.4 GHZ), TV/Radio/Data (3.700‐6.425 GHz), WLAN (5‐5.16 GHz), C band frequencies (5.15‐5.35, 5.47‐5.725, or 5.725‐5.875 GHz) and satellite communication (7.25‐7.9 GHz). The radiation patterns of suggested structure are steady during the operating band for which sample antenna has been fabricated and confirmed experimentally. It exhibits novel omnidirectional radiation characteristics in phi = 0° plane with lower cross‐polarization values.     

Miniaturized dual‐band metamaterial inspired antenna with modified SRR loading

A miniaturized dual‐band CPW‐fed Metamaterial antenna with modified split ring resonator (SRR) loading has been presented in this paper. Proposed antenna comprises a tapered rectangular patch with a slot in which an elliptically SRR has been loaded to achieve miniaturization. Proposed antenna shows dual band operations in the operating band 3.25‐3.42 and 3.83‐6.63 GHz, respectively. It has been observed that lower mode (at 3.36 GHz) is originated by means of modified SRR. SRR is being modified by small meandered line inductor which is placed instead of strip. This provides an extra inductance to SRR resulting miniaturization. Overall electrical size of the proposed antenna is 0.222 × 0.277 × 0.017 λ₀ at 3.36 GHz. Second band is due to coupling between feed and ground planes. The antenna offers an average peak gain of 1.72 and 3.41 dB throughout the first and second band respectively. In addition to that this antenna exhibits perfect omnidirectional and dipolar radiation patterns at xz‐ and yz‐ plane respectively. Due to consistent radiation pattern, ease of fabrication, and compact nature this antenna can be used for wireless applications such as worldwide interoperability for microwave access (WiMAX), industrial, scientific and medical (ISM) band, WLAN/Wi‐Fi bands.     

Bandwidth and gain‐enhanced composite right/left‐handed antenna for ultra‐wideband applications

A coplanar waveguide‐fed metamaterial antenna is presented for ultra‐wideband (UWB) applications. The proposed antenna is designed with single unit‐cell composite right/left‐handed transmission line (CRLH‐TL) loaded with a split‐ring resonator (SRR). The UWB characteristic is obtained by merging the zeroth‐order resonance of CRLH‐TL with two additional resonances due to the ground plane and SRR respectively. Subsequently, a partial reactive impedance surface is embedded on the rear side of the proposed antenna to enhance the realized gain without affecting the UWB response. The overall size of the antenna is 0.241λ_o x 0.267λ_o x 0.013λ_o (28.8 x 32 x 1.6 mm³), where λ_o is the free space wavelength at 2.51 GHz. The measured results indicate –10 dB fractional bandwidth of 139.19% (2.51‐14 GHz) with realized gains of 2.3, 4.6, and 6 dBi at the resonant frequencies 4, 7.84, and 10.29 GHz respectively. The measured peak realized gain is 6.6 dBi at 10.6 GHz. The radiation efficiency is above 63.85% for the entire UWB range with a peak value of 86.84%. A fairly stable group delay with variation within 1 ns is obtained throughout the operating frequency band. A good agreement has been observed between the measured and simulated results.     

基于CRLH—TL及CSRR的带通滤波器

首次提出一种复合左右手传输线零阶谐振器及互补谐振环的新型带通滤波器.设计方法利用左右手复合传输线的独有特性,即零阶谐振器中心频率与谐振器长度无关,能在特定非零频率上得到无限波长的特点,来构造环形滤波器,并且地板蚀刻了长方形互补谐振环结构.设计过程中使用了AnsoftHFSS软件进行全波仿真,经过多次仿真,通过调节参数大小优化设计,最终结果得到中心频率为1.85GHz、带宽为0.1GHz的新型带通滤波器.在达到同样效果的前提下,减小尺寸,单个谐振器与传统相比体积减少了近80%,长方形CSBR还提高了传输特性.上述结构的实现对于左手材料在微波器件中的发展有一定的促进作用,进一步扩大了左手材料的应用范围.     

新型微带带通滤波器设计

提出一种新型微带带通滤波器设计，它是由带有J-变频器的零阶谐振ZOR（zeroth-order resonant）系统构成。零阶谐振系统以互补分裂谐振环和一系列沟道组成的左手材料LHM（Left—HandedMaterial）为基本单元，在传统设计的基础上进行改进．得到适合具有严格设计要求的滤波器设计使用模型，并给出此零阶谐振系统的共振频率和导纳斜率参数的确定方法。实验表明，该微带带通滤波器的模拟量与测量之间存在最佳关系，并具有高选择性能、对称的响应曲线以及良好的通带带宽控制性能。     

A Compact Zeroth‐Order Resonant Antenna on Vialess CPW Single Layer

In this letter, a novel zeroth‐order resonant (ZOR) antenna on vialess co‐planar waveguide (CPW) is proposed. It is based on a composite right/left‐handed CPW transmission line. To achieve a compact size, this antenna utilizes the ZOR condition, and its reactive parameters determine the resonant frequency. Each unit cell is composed of a metallic top patch and meander lines. Since it is realized on the CPW single layer, the proposed antenna has the benefits of being a compact size and easy to fabricate. The bandwidth of 6.8% and efficiency of 62% are experimentally achieved. Its bandwidth is enhanced compared with other ZOR antennas.     

CPW‐Fed Arbitrary Frequency‐Switchable Antenna Using CRLH Transmission Line

A novel frequency‐switchable antenna that uses PIN diodes and a composite right‐ and left‐handed transmission line (CRLH TL) is proposed. The CRLH TL provides multi‐order resonance, including a zeroth‐order resonance (ZOR), and its shunt stub determines the ZOR frequency. Thus, the resonant frequency is arbitrarily chosen by lumped chip inductors on the shunt stub. Two prototypes are designed using different chip inductors while maintaining the antenna geometries. Antenna #1 can switch the resonant frequency from 1.8 GHz to 2.3 GHz. Antenna #2 can switch its resonance from 0.9 GHz to 2.3 GHz.     

基于CRLH TL的小型化宽频带手机天线设计

主要阐述基于复合左右手传输线(CRLH TL)零阶谐振模设计小型化宽频带的手机天线。该天线低频段由尺寸较大的零阶谐振天线决定,高频段由尺寸较小的零阶谐振天线决定,尺寸较大的零阶谐振天线的右手模式与尺寸较小的零阶谐振天线的零阶谐振模谐振在相邻的频带上实现频带融合,从而扩展高频段的带宽。该天线覆盖了GSM900、PCS、UMTS、Bluetooth和ISM2400五个移动通信频带,天线厚度仅为1mm,所占面积为37×15mm2。测试结果与仿真结果吻合,满足移动通信终端对手机天线的要求。     

UWB Metamaterial-based miniaturized planar monopole antennas

In this paper, ultra wide band (UWB) metamterial based compact planar antennas have been designed and experimentally verified. Four novel unit cells have been realized and each unit cell dispersion characteristics are numerically calculated which follows CRLH-TL properties. These four CRLH-TL unit cells are loaded into monopole antennas which result, four open-ended MTM antennas respectively. Further, a novel via free version of CRLH-TL unit cells have been designed, which increases the fabrication flexibility. The compactness has been achieved by realizing ZOR (zeroth order resonance) mode and its bandwidth is increased by realizing small shunt capacitance and large shunt inductance. Further, by optimizing CRLH-TL unit cells, two closely spaced zeroth-order and first-order resonance modes are merged into a single pass band, which gives wide bandwidth. The each proposed antenna has a compact dimension of 0.27 λ₀ × 0.19 λ₀ × 0.02 λ₀ (22 × 15 × 1.6 mm³), where λ₀ is a free space wavelength at 3.8 GHz. The four proposed antennas have S₁₁ < −10 dB impedance bandwidths of 8.4 GHz, 8.5 GHz, 8.2 GHz and 8.3 GHz respectively. The optimum gain, good efficiency, desired radiation characteristics in frequency domain analysis and less distortion of waves in time domain analysis have been achieved for proposed antennas, which are most suitable for UWB applications. The CST-MWS has been used for the parametric study of the proposed antennas. A good agreement has been observed between simulated and experimental results.