Study of miniaturized E‐patch antenna loaded with novel E‐shape SRR metamaterial for RFID applications

A new design of compact micro strip antenna, based on a newly structure "E"SRR of metamaterial is proposed and designed using CST Microwave Studio. It has been found that the characteristics of new micro strip antenna with novel designed metamaterials placed in the same plane as the radiating element are comparable to the conventional patch antennas, whereas its gain, directivity, and radiating efficiency are remarkably improved. For the design and fabricated antenna, it shows that with the addition of split ring resonator, the frequency has been shifted from 2.38 GHz to 2.4 GHz. The return loss of this antenna increased from ?60 dB to ?70 dB. The realized gain increased from 7.1 dbi for the antenna alone to 7.31 dbi for the meta‐material antenna. Prototype for all antennas are fabricated and measured. Good agreement between the measured and simulated results is achieved.     

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.     

An SRR based miniature implantable antenna with a slit loaded ground at MedRadio and ISM bands for biotelemetry applications

A miniaturized implantable microstrip split‐ring antenna (IMSRA) is proposed for wireless biotelemetry. The IMSRA takes up a miniaturized volume of 153.35 mm³ (10.5 × 11.5 × 1.27) and provides a dual‐band operation in 360 to 620 MHz and 2.32 to 2.54 GHz that covers The Medical Device Radiocommunications Service (MedRadio) (401‐406 MHz) and Industrial, Scientific, and Medical (ISM) (433‐434 MHz and 2.4‐2.48 GHz) bands. The principal part of the radiator consists of three homocentric split‐ring elements. In addition, three conductor paths located between the split rings are used for precise adjustment of the frequency. In order to reduce the antenna size, a shorting pin is appropriately inserted between one of the metallic rings and the ground plane. The impedance matching of the antenna is improved by the use of a hook‐shaped slit placed on the ground plane. For verification of the in vivo operation, the proposed IMSRA was measured in two separate skin‐mimicking gels for MedRadio and ISM bands. A prototype was also tested in the skin tissue sample of a donor rat. The proposed antenna offers 53% (360 ~ 620 MHz) bandwidth at 490 MHz and 9% (2.32 ~ 2.54 GHz) bandwidth at 2.43 GHz. The IMSRA exhibits well‐behaved radiation patterns and SAR values at the respective bands.     

一种新型加载超材料的卫星导航天线设计

设计了一款工作在1.575 GHz的单频天线和一款在1.2 GHz~1.4 GHz表现磁负特性的超材料结构单元。对单频天线接地板加载两个超材料结构单元,可以使天线工作在1.268 GHz和1.575 GHz。其中,较高的谐振频率是由天线自身产生,较低谐振频率是由超材料结构单元的加入激发产生。该天线具有结构紧凑、频带宽、体积小、易于加工等特点。单频天线加工了实物,仿真结果与实测结果基本一致。     

High performance microstrip monopole antenna with loaded metamaterial wire medium superstrate

A novel design of printed monopole antenna loaded with wire medium is developed for radar applications. The advocated design aims to simultaneously enhance the gain and bandwidth of the proposed geometry. The proposed antenna is composed of a circular patch etched with double C‐shaped slots and the ground is defected to achieve wide bandwidth. Wire medium superstrate and a metal reflector are implemented to provide high gain. The promising tunable wire medium superstrate consists of a periodic array of parallel metallic wires arranged in a rectangular pattern that mimic the behavior of epsilon‐near‐to‐zero (ENZ) metamaterial. This medium is suspended at a distance of a quarter‐wavelength in air above the antenna to provide the optimum gain and reduce the side lobes level. Prototype of the optimized antenna is fabricated using Rogers's substrate to offer ?10 dB bandwidth over the entire frequency range (900 MHz to 2.85 GHz). Details of the design process are investigated through full wave electromagnetic simulations performed by CST software. Experimental results of the fabricated prototype are presented and also compared with simulation results where an appreciable agreement between them is demonstrated.     

Planar UWB antenna with modified slotted ground plane

A compact coplanar waveguide‐fed (CPW) monopole antenna for ultra‐wideband wireless communication is presented. The proposed antenna comprises of a CPW‐fed beveled rectangular patch with a modified slotted ground. The overall size of the antenna is 30 mm × 27 mm × 1.6 mm. The lower edge of the band is attained by properly decoupling the resonant frequencies due to the extended ground plane and the beveled rectangular patch of the antenna. The upper edge of the radiating band is enhanced by beveling the ground plane corners near the feed point. Experimental results show that the designed antenna operates in the 2.7–12 GHz band, for S₁₁ ≤ ?10 dB with a gain of 2.7–5 dBi. Both the frequency domain and time domain characteristics of the antenna are investigated using antenna transfer function. It is observed that the antenna exhibits identical radiation patterns and reasonable transient characteristics over the entire operating band. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

Miniaturized omni-directional ZOR antenna with its co-equal circuit for 5G applications

Microsystem Technologies - This paper presents a hexagonal-shaped omni-directional Zeroth Order Resonator (ZOR) antenna for 5G application. 5G which is 1000 times faster than 4G technology, works...     

Equilateral triangular patch antenna for UHF RFID applications

This article proposes an equilateral triangule‐shaped patch antenna for radio frequency identification (RFID) applications in the 900 MHz (902–928 MHz) ultra high frequency (UHF) band. To achieve optimal impedance matching and 10‐dB operating bandwidth at the desired band, the L‐shaped probe‐feed technique was used as the feeding structure of the proposed antenna. Furthermore, a near semicircular notch was also loaded into the patch so that good circularly polarized (CP) radiation can be generated from the proposed patch antenna. By simply shifting the position or radius of this notch, the CP frequency can be varied with ease. Here, 10‐dB impedance bandwidth and 3‐dB axial ratio bandwidth of 25 and 3% were achieved. Furthermore, stable gain variation of approximately 6 dBi was also exhibited across the RFID UHF band. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:580–586, 2014.     

A novel wideband circularly polarized modified square‐slot antenna with loaded strips

In this article, a novel inverted L‐shaped microstrip‐fed wideband circularly polarized (CP) modified square‐slot antenna is designed. By cutting a pair of triangle chamfers and introducing a pair of triangle patches at the square‐slot, the antenna achieves a wideband CP radiation. Moreover, CP performance of the antenna can also be remarkably enhanced by protruding an L‐shaped strip and embedding a tuning rectangle slot into the slot ground. The measured results demonstrate that the axial‐ratio bandwidth for AR < 3 is 75.1% (from 4.45 to 9.8 GHz) and the impedance bandwidth (|S₁₁| < ?10 dB) reaches 65.8% (from 4.95 to 9.8 GHz). In addition, surface current studies are performed to illustrate the operating mechanism of CP operation, and the antenna has bidirectional radiation characteristics with an average gain of ~4 dBic within the CP band.     

A circular patch antenna with parasitic element for UHF RFID applications

This article initially proposes a directly‐fed circular patch antenna with L‐shaped ground plane for Radio Frequency Identification (RFID) applications in the 900 MHz (902?928 MHz) ultrahigh frequency (UHF) band. To achieve circularly polarized (CP) radiation, two arc‐shaped notches are loaded into the main patch. To enhance the CP bandwidth so that the proposed antenna can also cover the UHF RFID band for Europe (866?869 MHz), a parasitic element is printed besides the main patch. Experimental measurements show that the 10‐dB return loss bandwidth of the proposed antenna was 30.95% (833?1138 MHz) and its corresponding 3‐dB axial ratio bandwidth was 8.95% (865?946 MHz). Good gain and radiation efficiency of more than 7 dBic and 90%, respectively, were also exhibited across the two desired UHF RFID bands. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:681–687, 2015.     

A modified fractal‐shaped slotted patch antenna with defected ground using metasurface for dual band applications

A novel modified fractal‐shaped slotted patch antenna employing metasurface at bottom plane along with partial ground has been proposed in this work for dual band applications with significant gain. A 4 × 5 order metasurface has been formed in the ground plane by introducing a periodic combination of two L‐type patches with centered C‐type shaped patch. The top conductor and the ground plane are designed on a 1.6 mm thick FR4 dielectric with the dimension of 28 × 28 mm². The antenna is designed in such a way that it operates over the dual frequency ranges viz., 1.80 to 5.70 GHz and 10.38 to 10.94 GHz. The maximum return loss of 21 dB has been achieved over 2.60 GHz while the maximum realized gain of 7.16 dBi has been obtained at 10.92 GHz. The designed antenna offers omnidirectional radiation characteristics in the first band while directional radiation characteristics have been observed in the second band. The proposed antenna can be utilized for WiMAX 3.5/5.5 GHz, mobile, radio astronomy, and microimaging in medical analysis.     

Miniaturized frequency reconfigurable pentagonal MIMO slot antenna for interweave CR applications

In this article, a miniaturized 4‐element frequency reconfigurable multiple‐input‐multiple‐output (MIMO) antenna system is presented. The proposed design is low profile with planar configuration. The design consists of pentagonal slot‐based frequency reconfigurable antenna elements. Varactor diodes are used to change the capacitive reactance of the slot. The MIMO antenna system can be tuned over a frequency band covering 3.2 to 3.9 GHz with at least 100 MHz bandwidth within each band. The proposed antenna covers several commercial standards including WiMAX (3.4‐3.6 GHz), TDD LTE (3.6‐3.8 GHz), and Wi‐Fi 802.11y (3.65‐3.7 GHz), along with several other bands. The proposed design was realized on a board of dimensions 60 × 120 mm². The isolation between adjacent antenna elements is improved using slot‐line based defected ground structures (DGS). The antenna maintains a minimum isolation of 10 dB in its entire covered operating bands. The antenna is also analyzed for its far‐field characteristics and MIMO performance parameters. The proposed design is suitable to be used in mobile handsets for cognitive radio (CR) platforms.     

A novel differential filtering patch antenna with high selectivity

A novel differential filtering antenna with high selectivity is proposed. The antenna is mainly composed of three different‐size patches, a slot, a pair of differential feeding lines, and a line resonator. An air gap is adopted to improve the impedance bandwidth and the filtering performance. The line resonator helps to generate high common‐mode (CM) rejection. Owing to the parasitic concave and convex patches, the filtering performance and the bandwidth of the antenna are enhanced. The parasitic concave patch affects the lower band‐edge selectivity while the parasitic convex patch influences the upper band‐edge selectivity. In addition, the frequencies of two radiation nulls can be controlled independently to achieve two high sharp roll‐off rates by adjusting the lengths of the parasitic patches. Considerable impedance matching bandwidth is achieved through an aperture coupling. Finally, a prototype of the differential filtering antenna is fabricated and tested. The measured results are in good agreement with the simulated results, showing an impedance bandwidth of 9.9% and an average realized gain of 7.5 dBi. Besides, two filter zero transmissions located at 3.40 and 3.84 GHz produced two radiation nulls.     

Planar nested square fractal patch antenna for multi-band wireless applications

Microsystem Technologies - In this paper, a nested square ring-shaped antenna is presented for multi-band operation. The proposed patch antenna consists of a center square with outer rings shaped...     

Design of circular patch antenna with a high gain by using a novel artificial planar dual‐layer metamaterial superstrate

This study presents a new dual‐layer metasurface structure proposed to enhance the performance of a circular patch antenna. A novel unit cell planar metasurface is characterized by nearly equal enhanced effective permeability and permittivity ε_r ? μ_r > 1 at the resonant frequency. In addition, a 5*5 array of these unit cells are used as a superstrate over a circular patch antenna which is fed by 50 Ω microstrip line and operating at 2.45 GHz for improving the antenna performance. The patch antenna gain is increased by creating an in‐phase electric field area on the top surface of the metasurface. The obtained results showed that the maximum gain of the antenna increased from 2.31 dBi to 7.5 dBi. A 30% increase in the bandwidth is also remarked. The proposed antenna with metasurface occupies an overall volume of 1.01λ_g ×1.01λ_g ×0.025λ_g . The simulation analysis and measured results were performed using the microwave studio, high frequency structure simulator software, and vector network analyzer. The proposed antenna prototype has been fabricated. The measured results indicate that the antenna has a good impedance matching in the desired operating band (2.37‐2.49 GHz) with the resonant frequency of 2.44 GHz which make the proposed antenna appropriate for microwave applications.     

Integrated Vivaldi antenna for UWB/diversity applications in vehicular environment

This article presents the design of a three‐port diversity antenna capable of producing three‐directional radiation pattern for vehicular communications. The proposed antenna consists of three uncorrelated Vivaldi antennas that are interconnected and developed on a single printed circuit board. Unlike many other antennas reported for the vehicular environment, the proposed antenna offers ultra‐wideband characteristics with end‐fire radiation pattern leading to high realized antenna gain. The integrated antenna has a footprint of 65 × 40 × 1.6 mm³ and offers 6 GHz impedance bandwidth extending from 5 to 11 GHz. The port‐to‐port isolation is greater than 20 dB within the operating bandwidth. Furthermore, the diversity performance of the proposed three‐port antenna system is evaluated and presented. The calculated envelope correlation coefficient, diversity gain, and mean effective gain are well above the minimum requirement. The prototype antenna is fabricated and the experimental results are presented.     

A metamaterial hepta‐band antenna for wireless applications with specific absorption rate reduction

Present article embodies the design and analysis of slotted circular shape metamaterial loaded multiband antenna for wireless applications with declination of SAR. The electrical dimension is 0.260 λ × 0.253 λ × 0.0059 λ (35 × 34 × 0.8 mm³) of proposed design, at lower frequency of 2.23 GHz. The antenna consists of circular shape rectangular slot as the radiation element loaded with metamaterial split ring resonator (SRR) and two parallel rectangular stubs, etched rectangular single complementary split‐ring resonator (CSRR) and reclined T‐shaped slot as ground plane. Antenna achieves hepta bands for wireless standards WLAN (2.4/5.0/5.8 GHz), WiMAX (3.5 GHz), radio frequency identification (RFID) services (3.0 GHz), Upper X band (11.8 GHz—for space communication) and Lower K_U band (13.1 GHz—for satellite communication systems operating band). Stable radiation patterns are observed for the operating bands with low cross polarization. The SRR is responsible for creating an additional resonating mode for wireless application as well as provide the declination in SAR about 13.3%. Experimental characteristic of antenna shows close agreement with those obtained by simulation of the proposed antenna.     

A novel dual‐mode patch antenna with pattern diversity and beam‐tilting for aircraft applications

A dual‐mode patch antenna with pattern diversity that is beam‐tilted in a specific direction is presented. By placing a rectangular metal cavity below the circular patch and simultaneously shorting one end of the patch, the antenna produces tilted beams for dual‐mode radiation patterns. One pattern is excited using a proximity‐fed L‐shaped probe that generates a beam with a tilt angle of 25° from the broadside direction. The second pattern is excited using a coplanar waveguide (CPW)‐based feeding network that generates two beams with a tilt angle of θ_max = ±45° in the directions of ?_max = 70° and ? 70°. The tilt angle can be varied by adjusting the metal cavity's length. A prototype antenna for operation at 2.38 GHz was fabricated and measured. The results indicate that the overlapped bandwidth (|S₁₁| < ?10 dB) for the two patterns is 330 MHz (2.22‐2.55 GHz). The measured peak gains for the two patterns are 6.74‐6.94 dBi and 5.82‐6.74 dBi, respectively. The isolation between the two ports is 18 dB.     

Eccentric annular slot patch antenna with frequency agility for UHF RFID reader applications

The design of a simple ultrahigh frequency RFID (radio frequency identification) reader antenna that can operate within the North America RFID band (902–928 MHz) is studied. To generate circular polarization (CP) radiation in this band, a novel method of loading two narrow open‐ended slots (slits) into an eccentric annular slot patch is proposed. To allow optimum impedance matching with enhanced CP bandwidth, the radiating patch is loaded to an L‐shaped ground plane. From the experimental results, the proposed antenna can yield an impedance bandwidth (10‐dB return loss) between 650 MHz to 1125 MHz, while good CP bandwidth (3‐dB axial ratio, AR) from 901 MHz to 930 MHz is also attained. Furthermore, gain level and efficiency of more than 7.8 dBic and 90%, respectively, were also measured. By simply removing one of the slits, this proposed antenna can also be modified to operate within the China (840–846 MHz) and European (865–868 MHz) RFID band.     

Wide bandwidth microstrip antenna with defected patch surface for low cross polarization applications

A simple and single element wide slot dipole loaded shorted rectangular microstrip antenna has been proposed and investigated experimentally for broad impedance bandwidth and improved cross polarized (XP) radiation compared to maximum co‐polarized (CP) gain without changing the co‐polarized (CP) radiation pattern. Around 23‐35 dB isolation between CP and XP radiation along with 25% impedance bandwidth is achieved with the proposed structure. The measured gain of the antenna is around 6.2 dBi over the entire band. The present antenna is very simple and easy to manufacture. Unlike the other structures, the present one is free from back radiation in terms of XP fields. The design of the antenna structure is theoretically justified and rigorously analyzed. The present investigation provides an insightful, clear visualization‐based understanding of the concurrent improvement in both the impedance bandwidth and XP performance with the present structure.