Dual‐band dual‐sense circularly polarized antenna based on crossed dipole structure for WLAN/WiMAX applications

This paper presents a new approach to design dual‐band antenna with dual‐sense circularly polarized (CP) operation. A principle for CP radiation is the use of two orthogonal dipoles and properly choosing their lengths can produce either right‐hand CP (RHCP) or left‐hand CP (LHCP) operation. In the proposed structure, the lower frequency band at 2.4 GHz is designed with RHCP radiation and LHCP is the operating mode of the higher band at 3.5 GHz. For verification, an antenna prototype is fabricated and measured. Measured data indicate that good performances over the RHCP and LHCP bands can be obtained with usable bandwidths of 2.9% (2.36‐2.43 GHz) and 1.7% (3.48‐3.54 GHz). Along with this, it also observes good unidirectional radiation patterns and the measured broadside gains are around 7.7 and 7.4 dBic across these frequency ranges.     

A novel millimeter‐wave dual‐band circularly polarized dielectric resonator antenna

In this article, a novel dual‐band circularly polarized (CP) dielectric resonator antenna (DRA) for millimeter‐wave (MMW) band is presented. The rectangular dielectric resonator with layered truncated corners is excited by a microstrip‐coupled cross‐slot. CP radiations in the lower band are realized by utilizing two quasi‐TE₁₁₁ modes operating at 21.7 GHz and 23.8 GHz, while CP radiations in the upper band are obtained by exciting a quasi‐TE₁₁₃ mode at 28.2 GHz. The dual‐band DRA is fabricated and measured. Due to the higher order mode, the average gain of the DRA in the upper band is about 3 dB higher than that in the lower band. The measured impedance bandwidths (|S₁₁| < ?10 dB) are 17.0% (20.5‐24.3 GHz) and 15.2% (26.1‐30.4 GHz), while the measured axial ratio (AR) bandwidths (AR < 3 dB) are 12.8% (21.2‐24.1 GHz) and 5% (27.4‐28.8 GHz). In addition, the peak gain values are 5 and 8 dBic.     

A high‐gain dual‐band directional/omnidirectional reconfigurable antenna for WLAN systems

A high‐gain dual‐band antenna for the wireless local area network system is presented in this article. Two symmetrical linear arrays can be dynamically reconfigured that could switch radiation pattern with a switchable feed circuit between direction and omnidirection. The antenna can also be used for a pattern diversity antenna for the multiple‐input–multiple‐output communication systems. The design process for the antenna system is given, and the parameters and characteristics of the antennas are achieved by the method. Measured return losses, isolation, and radiation patterns are in good agreement with the simulated ones, which illustrates that the method is valid and the antenna system can be integrated with pattern reconfigurable and pattern diversity applications. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Dual‐band dual‐polarized compact planar monopole antenna for wide axial ratio bandwidth application

In this article, a geometrically simple, microstrip line‐fed planar monopole structure with slanting edge ground plane is designed to realize the dual‐band dual‐polarized operation. The proposed antenna consists of a rotated U‐shaped patch and an electromagnetically coupled L‐shaped parasitic radiating element. Owing to the combination of microstrip line‐fed radiating patch and a slanting‐edge rectangular ground plane on the opposite side of the substrate, the proposed dual‐band antenna can generate broad axial ratio bandwidth (ARBW) in the upper frequency band. The overall dimension of the prototype is only 32 × 32 × 1.6 mm³. The measured results validate that the proposed antenna has two operational frequency bands, 29.84% (1.54‐2.08 GHz) for linearly polarized radiation and 71.85% (3.96‐8.4 GHz) for circularly polarized radiation. Measured result shows that 3‐dB ARBW of the proposed antenna is 73.54% (3.80‐8.22 GHz) in the higher frequency band. It shows that the higher frequency band exhibits a left‐hand circularly polarized radiation in the boresight direction.     

Dual‐band dual‐polarized hybrid aperture‐cylindrical dielectric resonator antenna for wireless applications

A dual‐band dual‐polarized hybrid aperture‐cylindrical dielectric resonator antenna (CDRA) is examined in this article. Inverted regular pentagon shaped aperture is not only used to launch two radiating hybrid modes (HEM_11δ and HEM_12δ mode) in CDRA but also act as a radiator. Out of two frequency bands, the lower frequency band is linearly polarized while upper frequency band is the combination of both circular and linear polarization. A circular polarization (CP) characteristic in upper frequency band is created by loading quarter annular stub with microstrip line. LHCP/RHCP can easily be controlled by alternating the position of quarter annular stub. It is operating over two frequency ranges i.e. 2.48‐2.98 GHz and 4.66‐5.88 GHz with the fractional bandwidth 18.31% and 23.14% respectively. Axial ratio bandwidth (3‐dB) is approximately 8.78% (4.9‐5.35 GHz) in upper frequency band. The proposed antenna design is suitable WiMAX (2.5/5.5 GHz) and WLAN (2.5/5.5 GHz) applications.     

Dual‐band circularly polarized dielectric resonator antenna for wireless applications

This letter investigates an integrated antenna configuration for WLAN/WiMAX applications. The proposed composite antenna configuration is simply the grouping of ring dielectric resonator along with reformed square‐shaped slot antenna. Three significant characteristics of proposed article are: (1) aperture act as magnetic dipole and excite HE_11δ mode in ring dielectric resonator antenna; (2) reforming of square aperture generates orthogonal modes in ring DRA and creates CP in lower frequency band; (3) annular‐shaped Microstrip line along with reformed square aperture creates CP wave in upper frequency band. With the purpose of certifying the simulated outcomes, prototype of proposed structure is fabricated and tested. Good settlement is to be got between experimental and software generated outcome. Experimental outcomes show that the proposed radiating structure is operating over 2 frequency bands that is, 2.88‐3.72 and 5.4‐5.95 GHz. Measured 3‐dB axial ratio bandwidth in lower and upper frequency band is approximately 9.52% (3.0‐3.4 GHz) and 5.85% (5.64‐5.98 GHz), respectively. These outcomes indicate that the proposed composite antenna structure is appropriate for WLAN and WiMAX applications.     

A Dual‐band and dual‐polarized antenna array for 2G/3G/LTE base stations

A dual‐band antenna array is proposed for the application of base station (BS) in 2G/3G/long term evaluation (LTE) mobile communications. This antenna consists of two independent ±45° dual‐polarized arrays, one of which operates from 1.71 to 2.17 GHz, and the other of which is designed from 2.5 to 2.69 GHz. The proposed BS antenna array has a high isolation of greater than 29 dB and high front‐to‐back ratio of more than 26 dB at the operating frequencies. The measured peak gain is 17.9 and 18.1 dBi for the lower and upper bands, respectively, and the cross polarizations isolation (CPI)(within ±60º of the mainlobe) is 16 dB lower than the broadside co‐polarization. It was confirmed that the proposed antenna array meets the communication standards in China. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:154–163, 2016.     

A dual‐band and wideband omnidirectional circularly polarized antenna based on VO2

In this article, a dual‐band and wideband omnidirectional circularly polarized (CP) antenna based on the vanadium dioxide (VO₂) is investigated. The operating bandwidth of such an antenna can be regulated by altering the outside temperature (T), which is attained by the insulator‐metal transition of VO₂. The omnidirectional CP antenna is based on a loop antenna‐dipole model, which is composed of four tilted metal and VO₂ resonant units that are loaded around a cuboid and a feeding network for broadening bandwidth. The simulated results show that when T = 50°C (State I), the 10‐dB impedance bandwidth is 45.7% (1.67‐2.66 GHz), and the 3‐dB axial ratio (AR) bandwidth is 40% (1.9‐2.85 GHz). When T = 80°C (State II), the 10‐dB impedance bandwidth is 13.8% (1.62‐1.86 GHz), and the 3‐dB AR bandwidth is 21.8% (1.68‐2.09 GHz). In order to further characterize the concept of the proposed antenna, the related parameters of such an antenna are studied using simulation software HFSS.     

A dual‐broadband circularly polarized halved falcate‐shape printed monopole antenna

A halved falcate‐shape dual‐broadband circularly polarized printed monopole antenna is proposed. To generate the equal amplitude orthogonal modes, two halved falcate‐shaped antenna are used. Also, to provide the 90° phase difference between the two modes, three stubs are used in the ground plane of the antenna. The proposed antenna provides 22.6 (1.36–1.72 GHz) and 44.4% (5.25–8.25 GHz) 3 dB axial ratio bandwidth over the lower and upper bands, respectively. By adjusting the parameters of the antenna, the lower and upper band center frequencies can be tuned individually. The proposed antenna is fabricated, and results are compared with those of the simulation. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

An inverted‐F antenna design for WLAN/WiMAX dual‐network applications

This study designed a compact size (45 mm × 9 mm × 1.6 mm) stand‐alone dualband inverted‐F antenna (IFA) printed on a low‐cost FR4 substrate for dual‐network WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5 GHz) operating bands. To achieve broad 10‐dB bandwidth of more than 45% and 31% for the lower and upper operating bands, respectively, the techniques of shorting the open‐end of the microstrip feed line to the driven monopole and loading a C‐shaped parasitic element with dissimilar arm lengths into the opposite side of the IFA were introduced. Further experimental results also show that the proposed IFA have efficiencies of more than 60% throughout the bands of interest. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:523–528, 2014.     

A dual‐band circularly polarized antenna with aid of dual cylindrical dielectric resonator blocks

In this communication, a dielectric resonator based circularly polarized antenna is designed and investigated. A modified aperture is used to excite dual cylindrical dielectric resonator (CDR) blocks. Two important characteristics of the proposed radiator that makes it all the more attractive are as follows: (i) excitation of dual radiating modes that is, HEM_11δ and TE_01δ mode in cylindrical DR along with the support of dual‐band circularly polarized (CP) waves; (ii) arrangements of dual CDR blocks to reduce the Q‐factor which is useful to enhance the impedance bandwidth of both frequency bands. Fabrication as well as experimental measurement of the antenna prototype has been done for verifying simulation outcomes. This antenna design operates over dual frequency bands, that is, 5.01‐6.41 GHz and 7.3‐7.9 GHz with the fractional bandwidth of 24.73% and 9.39%, respectively. It supports CP waves over the frequency range 6.1‐6.5 GHz and 7.4‐7.8 GHz. The proposed antenna backs right‐hand circularly polarized (RHCP) radiation with an average gain of 4.5 dBi. These characteristics make it well fitted for WLAN, WiMAX (5.2/5.5/5.8 GHz), and downlink defense purpose satellite communication (7.2‐7.7 GHz).     

Compact dual‐band ring dielectric resonator antenna with moon‐shaped defected ground structure for WiMAX/WLAN applications

In this article, compact ring‐shaped dielectric resonator antenna (DRA) along with moon‐shaped defected ground structure (DGS) was studied. The proposed antenna was fed by microstrip line shifted from center position, which excited TE_01δ mode in ring DRA. Moon‐shaped DGS was acting as a radiator and also reduced the size of proposed antenna by an amount of 14.87% (lower frequency band) and 48.77% (upper frequency band). The proposed antenna was designed to resonate at two different frequencies namely 2.24 and 5.82 GHz with a fractional bandwidth of 30.17% and 22.14%, respectively. Based on optimized design parameters, archetype of antenna structure has been constructed and measured successfully, which shows good agreement with simulated ones. The proposed antenna design was suitable for WLAN (2.4/5.2/5.8 GHz); WiMAX (2.5/5.5 GHz); AMSAT (5.6/5.8 GHz); and WAVE (5.9 GHz) bands. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:503–511, 2016.     

Integrated circular polarized microstrip antenna with dual‐mode‐polarization insensitive characteristics

A dual‐mode circularly polarized compact antenna with integrated left‐hand and right‐hand circular polarization (LHCP and RHCP) is presented in this work. A multilayer arrangement of a square patch and square ring structure with an irregular transmission line is analyzed for dual‐band, dual‐CP operation. To realize dual mode propagation the proposed structure is excited using electromagnetic coupling technique. Succeeding proximity feeding with T‐stub match is analyzed, which conveys impedance bandwidth of 180 and 300 MHz within |S₁₁| < ?10 dB at 3.5 and 5.5 GHz. The designed CP elements is suitably arranged with feed line for generating two orthogonal polarization of equal amplitude and a 90° phase difference at both the resonant modes (TM₁₀ and TM₀₁). Alterable LHCP and RHCP performance is realized by altering the compensated position and peculiar angle. Having both LHCP and RHCP polarization this design shows polarization insensitive characteristic. Each LHCP and RHCP antenna element accomplished a 3‐dB AR of 70 and 120 MHz with a gain up to 6 dBi. With a low profile of 0.27λ₀ × 0.27λ₀ × 0.04λ₀, the CP antenna is fabricated, and the performance is validated through experimental analysis. With all the viable characteristics, the antenna is proposed for Wi‐MAX/WLAN communication.     

A hexa‐band dual‐sense circularly polarized antenna for WLAN/Wi‐MAX/SDARS and C‐band applications

In this article, a compact single fed hexa‐band circularly polarized (CP) monopole antenna using split ring resonators (SRRs) on the partial ground plane is designed and experimentally investigated. The loaded SRR elements generate multiple circularly polarized bands along with a reduction in antenna size. The multiband can be controlled by changing the configuration of SRRs and their position on the ground plane without altering the monopole radiator. To illustrate the CP mechanism and multiband operation of the proposed configuration, the surface current density has been studied. The antenna is fabricated on RT Duroid 5880 substrate of permittivity 2.2 with a total size of 47 × 40 × 1.57 mm³. Compared with the existing antenna designs, the proposed structure is compact and demonstrates improved multiband performance with circular polarization.     

A dual‐band dual‐polarized end‐loaded quasi‐open‐sleeve dipole antenna with stable pattern for wireless local area network applications

This article presents a dual‐band dual‐polarized end‐loaded quasi‐open‐sleeve dipole antenna (ELQOSDA) with stable radiation patterns for WLAN applications. The ELQOSDA consists of an end‐loaded planar dipole and two parasitic strips. Dual polarization is obtained by two ELQOSDAs perpendicularly crossing, with some parts overlapped. The unidirectional stable radiation patterns are achieved by adding a square resonance ring between the ground plane and antenna. The ring has little influence on antenna performance at the lower frequency, but improves the coupling currents between the ground and antenna at the upper frequency. As a result, satisfactory dual band and broadside radiation performance is obtained. For demonstration, the proposed antenna is implemented. Measured dual‐band 10‐dB impedance bandwidths are 9.4% (2.33‐2.56 GHz) and 33.5% (4.23‐5.93 GHz) in the lower and upper bands, covering the entire WLAN 2.4/5.2/5.8‐GHz bands. Moreover, the measured antenna has a 6.7‐8.1 dBi broadside gain and stable radiation patterns over the whole operating band.     

A compact dual‐band filtering antenna for wireless local area network applications

A printed dual‐band filtering antenna with decent frequency selectivity at 2.45 and 5.2 GHz for wireless local area network (WLAN) applications is developed. The filtering antenna is compact, which comprises a tapped feed line, two dual‐band stub‐loaded open‐loop resonators, and a dual‐band bended monopole. It can be easily printed on a single layer PCB substrate with low profile and low cost. The entire structure is very simple compared with the previously reported dual‐band filtering antennas that requiring multi‐layer structures. The monopole functions as not only a radiator, but also the last resonator of a dual‐band filter. The developed antenna exhibits good frequency selectivity and out‐of‐band suppression. In addition, the two operation bands can be adjusted relatively individually. The proposed antenna is optimized and fabricated. The experimental results show it has good frequency selectivity at both 2.45 and 5.2 GHz, wide bandwidth 11.8% and 7.8%, and excellent out‐of‐band suppression.     

A dual‐band efficient circularly polarized rectenna for RF energy harvesting systems

A multilayered circularly polarized (CP), dual‐band, stacked slit‐/slotted‐patch antenna with compact size and with compact rectifier is offered for RF energy harvesting systems. The compact dual‐band CP antenna size is able to achieve by stacking slotted‐circular‐patch (SCP) on the substrate above the tapered‐slit‐octagon patch (TSOP). Dual‐band CP radiation is realized by stacking the SCP on the TSOP and the microstrip feedline with metallic‐via to SCP. Eight‐tapered‐slit with length difference of 6.25% are embedded along the octagonal directions symmetrically on the TSOP from the patch's center and two unequal size circular slots are embedded in diagonal axis onto SCP to produce dual‐orthogonal modes with almost equal magnitude for CP waves. The designed antenna is realized measured gain of greater than 5.2 dBic across the band (0.908‐0.922 GHz) with maximum gain of 5.41 dBic at 0.918 GHz and gain of greater than 6.14 dBic across the band (2.35‐2.50 GHz) with maximum gain of 7.94 dBic at 2.485 GHz. An overall antenna volume is 0.36λ _o × 0.36λ _o × 0.026λ _o (λ _o is free space wavelength at 0.9 GHz). A compact composite right‐/left‐handed (CRLH) based rectifier with dual‐band at 0.9 and 2.45 GHz is designed, prototyped, and measured. The right‐handed (RH) part of the CRLH transmission line (TL) is formed by a microstrip line. The left‐handed (LH) part of the CRLH‐TL is formed by lumped components. The measured RF‐DC conversion efficiency is 43% at 0.9 GHz and 39% at 2.45 GHz with rectifier size of 0.18λ _o × 0.075λ _o × 0.0002λ _o at 0.9 GHz.     

Semicircular shape hybrid reconfigurable antenna on Jute textile for ISM,Wi‐Fi,Wi‐MAX,and W‐LAN applications

This article presents the development of a conformal reconfigurable frequency circularly polarized jute textile antenna, working at 2.4, 3.5, 5.8, and 5.9 GHz in Wi‐Fi, Wi‐MAX, Industrial, Scientific and Medical radio bands and W‐LAN. The antenna topology is based on a semicircular structure as the main radiating component. The conductivity is realized by using copper paint, which was brush‐painted. The patch structure is rehashed in another side of the substrate against the ground with a rotation turn 180°. Two BAR64‐03 W PIN diodes switches are placed in between a semi‐elliptical structure and a rectangular structure on the bottom side of the ground plane. By governing the state of the switches, this antenna can operate at different operating frequencies. Furthermore, the antenna has an accomplished axial ratio (AR) of less than 3 dB for resonating frequencies at all four switching states. Other electromagnetic properties of the proposed jute textile antenna accomplished in simulations were confirmed through the measurement of the antenna in an anechoic chamber. The reconfigurable circularly‐polarized jute textile antenna shows a peak gain of 4.93, 5.67, 8.86, and10.07 dBi at 2.4, 3.5, 5.8, and 5.9 GHz (Wi‐Fi, Wi‐MAX, ISM, W‐LAN).     

Dual‐band circularly polarized antenna with harmonic suppression performance

A dual‐band circularly polarized (CP) antenna with harmonic rejection property is proposed in this paper. Four T‐shaped slits and two corner cuts are etched on the proposed microstrip patch antenna. Those structures can be used to tune the resonant frequencies of TM₀₁ mode and TM₀₃ mode of the antenna into the desired bands of 2.45 and 5.8 GHz with CP radiation. A shunt transmission line is employed not only to improve the impedance matching at 5.8 GHz but also to suppress the radiation at 4.9 GHz (second harmonic of 2.45 GHz). Meanwhile, two L‐shaped slits are etched on the feeding line to realize the harmonic rejection at 11.6 GHz (second harmonic of 5.8 GHz). The simulated and measured results show that this antenna has good dual‐band CP radiation property and harmonic suppression performance, which makes it a good candidate for the wireless energy harvesting system.     

Slot line fed dual‐band dipole antenna for 2.4/5.2 GHz WLAN applications

A printed slot line fed dual‐band coplanar dipole antenna having a dimension of 0.40λ_g × 0.20λ_g suitable for both 2.4 and 5.2 GHz (IEEE 802.11 b/g and 802.11 a) WLAN application is presented. The structure comprises of a slot line fed symmetrical L strips to achieve dual‐band operation. Design equations of the antenna are developed and validated on different substrates. The simulation and experimental results show that the proposed antenna exhibits good impedance match, gain, and stable radiation patterns in both the frequency bands. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2012.