Design of a compact U-shaped slot triple band antenna for WLAN/WiMAX applications

This article presents a small, low-profile planar microstrip antenna that is applicable for both WLAN and WiMAX applications. The goal of this paper is to design an antenna which can excite triple-band operation with appreciable impedance bandwidth to combine WLAN/WiMAX communication specifications simultaneously in one device. The designed antenna has a compact size of 10 × 26 mm². The proposed antenna consists of an inverted U-shaped slot radiator and a defected ground plane. Overall the design method and parametric study found appropriate dimensions, which provides three distinct bands I from 2.40 to 2.52, II from 3.40 to 3.60 and III from 5.00 to 6.00 GHz that covers entire WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5) bands. Finally, a prototype antenna was fabricated and experimentally characterized to verify the design concept as well as to validate the simulation results. Thus the simulation results along with the measurements show that the antenna can simultaneously operate over WLAN and WiMAX frequency bands.     

Automotive communication applications based circular ring antenna with reconfigurability and conformal nature

This work presents a compact and conformal frequency reconfigurable antenna for automotive applications. The antenna is designed on a liquid crystal polymer substrate of footprint 40 × 30 × 0.1 mm³. The proposed antenna is having coplanar waveguide feeding with a circular ring radiating element and a pair of parasitic circular elements to obtain the multiband operation. The proposed antenna is studied for frequency reconfigurable characteristics by placing the PIN diodes as switching elements in the desired locations and obtained the reconfigurability in the 4.5–6.5 GHz region. Further, the bending effects of the antenna with respect to its operating bands and the conformal effects with PIN diodes for the reconfigurable performance make this study a trailblazing work. The simulated and measured results describe that the on-glass conformal antenna is covering 1.58–2.33 (GPS, PCS, GSM1800/1900), 3.22–3.7 (WiMAX), and 4.25–6.8 GHz (WLAN, DSRC, WAVE, V2X) bands for vehicular communications with various switching cases. The obtained gain varies from 3.2 to 4.1 dB in the boresight direction and 6.9 to 9.8 dB in the lateral directions of the vehicle with placement on the vehicle body. As per the obtained results, the antenna is suitable to use for conformal usage on the windshield glass of the vehicle for connected driving scenarios.     

Design and realization of low profile dual-wideband monopole antenna incorporating a novel ohm (Ω) shaped DMS and semi-circular DGS for wireless applications

In this paper, a compact microstrip line fed dual-wideband printed monopole antenna (PMA) for wireless communication applications is presented. The proposed antenna consists of an asymmetric rectangular patch via a microstrip-fed line, an ohm (Ω) shaped DMS loaded at the rectangular patch, and dual semi-circular shaped DGS embedded in the partial rectangular ground plane. The combination of an ohm shaped DMS and two semi-circular DGS is used to broaden the bandwidth of the two bands and improve the return loss for the desired antenna. The measured 10 dB bandwidth for return loss are achieved to be 21.52% (3.40–4.22 GHz) and 47.32% (5–8.1 GHz) in the lower and upper band, respectively which covers the bandwidth requirements of 5.2/5.8 GHz WLAN and 3.5/5.5 GHz Wi-MAX application bands. Furthermore, the proposed antenna has a very simple planar structure and occupies a small area of only 621 mm² (23 mm × 27 mm). The proposed antenna has a desirable VSWR level, radiation pattern, radiation efficiency and gain characteristics which are suitable for wireless communication applications.     

A dual-band multiple-input multiple-output microstrip antenna with metamaterial structure for LTE and WLAN applications

A method to enhance the gain of microstrip dual-band multiple-input multiple-output (MIMO) antenna using partially reflective surface (PRS) layer is introduced and investigated in this paper. The proposed antenna consists of two FR4 substrates. The lower substrate has two radiating patches with parasitic elements that are supplied independently and create the MIMO property of the antenna. The upper substrate which is known as superstrate is arrays of PRS unit cells. The PRS layer printed on either side of a dielectric substrate and causes the antenna gain to increase in both frequency bands. The proposed antenna is appropriate for LTE (2.4–3.1 GHz) and WLAN (5.1–5.8 GHz) applications. The measured values of S₁₁ and S₂₂ parameters of the antenna are less than −10 dB and its FBR and gain are 12.5 dB and 5dBi, respectively. The average half power beam-width (HPBW) is roughly 108^○.     

一款低不圆度WLAN 双频天线的设计与实现

提出了一种改进型的应用于无线局域网的双频印刷单极子天线。该天线可以覆盖IEEE 802. 11a/ b/ g (2. 4 ~2. 484GHz,5. 15 ~5. 825GHz)频段标准,其回波损耗小于10dB 的阻抗带宽在2. 4GHz 频段可达290MHz(2. 28 ~2. 57GHz),在5GHz 频段可达5. 53GHz(4. 34 ~9. 87GHz)。另外,在工作频带内,还获得了良好的全向辐射方向图 和天线增益。该天线的总体尺寸为22mm×44mm,结构紧凑, 且具有不圆度低、成本低和易于集成等优点, 因此具有 十分良好的应用潜质。     

应用于WLAN和WiMAX的双频带印刷天线设计

提出了一种新型的用于WLAN/WiMAX通信系统的双频带印刷单极天线。通过改进的叉子形的辐射贴片,使天线在2.4 GHz频带内谐振。同时,在介质基板背面的引入寄生辐射贴片,利用与正面的辐射贴片的耦合效应,使天线谐振在5 GHz频带内。最终使得天线可以覆盖2.4/5.2/5.8 GHz WLAN 和5.5 GHz WiMAX频带。对加工后的天线模型测试表明,天线在工作频带内具有较好的全向辐射特性和可观的增益。因此,该天线在无线多频带通信系统中具有广泛的应用前景。     

Design of band-notched antenna with DG-CEBG

Ultra-wideband (UWB) disc monopole antenna with crescent shaped slot for double band-notched features is presented. Planned antenna discards worldwide interoperability for microwave access (WiMAX) band (3.3–3.6 GHz) and wireless local area network (WLAN) band (5–6 GHz). Defected ground compact electromagnetic band gap (DG-CEBG) designs are used to accomplish band notches in WiMAX and WLAN bands. Defected ground planes are utilised to achieve compactness in electromagnetic band gap (EBG) structures. The proposed WiMAX and WLAN DG-CEBG designs show a compactness of around 46% and 50%, respectively, over mushroom EBG structures. Parametric analyses of DG-CEBG design factors are carried out to control the notched frequencies. Stepwise notch transition from upper to lower frequencies is presented with incremental inductance augmentation. The proposed antenna is made-up on low-cost FR-4 substrate of complete extents as (42 × 50 × 1.6) mm³.Fabricated sample antenna shows excellent consistency in simulated and measured outcomes.     

A high gain dual-band printed antenna for LTE base stations with a corner reflector

A high gain dual-band printed antenna is proposed for LTE base stations applications. The established 60 × 60 mm² broadband antenna structure is composed of two perpendicular U-shaped and L-shaped monopole antennas which are located vertically on ground plane printed on 1.6 mm thick FR4 substrate. A metallized wall is connected to the substrate which forms a corner reflector. A coaxial cable at the common center of the monopoles is adopted to excite the antenna. Wise implementation of the conductive elements and finely tuning of the monopoles dimensions yield the excitation of two resonances and dual band operation achievement. The presented antenna achieves bandwidths of 1.61–1.86 GHz and 2.25–2.45 GHz suitable for LTE applications. Stable radiation pattern, small size, cost effective fabrication, and high peak gain values of 10 dBi and 9.5 dBi at two operating bands are the prominent features of the proposed antenna topology.     

Design of a patch antenna with square ring-shaped-coupled ground for on-/off body communication

Bio-telemetry is an advanced area of research that enables the transmission of biomedical parameters from human body to external monitoring device. Wearable antennas showing robust performance are attaining attention for RF bio-telemetry. A square ring-shaped ground antenna with a truncated patch is investigated for dual mode, on-body and off-body communication. The proposed antenna structure is analysed and optimised on a multi-layered flat tissue phantom. Proposed design resonates at 2.6 GHz with |S11| ?22 dB and at 5.2 GHz with |S11| ?35 dB on the phantom gel. Wide bandwidth of 520 MHz (2.33–2.85 GHz) and 620 MHz (4.78–5.4 GHz) efficiently covers ISM, LTE and WLAN bands and enables the antenna to withstand frequency detuning due to different body postures. Antenna shows maximum radiation efficiency of 15% at 2.45 GHz band when placed close to the tissue. Low specific absorption rate (SAR) value of 0.459/0.523/0.303 W/Kg at 2.45/2.6/5.2 GHz ensures the tissue safety.     

Broadband sub-6 GHz flower-shaped MIMO antenna with high isolation using theory of characteristic mode analysis (TCMA) for 5G NR bands and WLAN applications

A small size neutralization line integrated flower-shaped MIMO antenna is designed and analyzed for sub-6 GHz type 5G NR frequency bands like n79 (4400–5000 MHz), n78 (3300–3800 MHz), n77 (3300–4200 MHz), and WLAN (5150–5825 MHz) applications. The novel approach of theory of characteristic mode analysis (TCMA) is introduced to provide physical insight of the designed structure and its characteristics behavior. Due to the suggested modifications in the geometry, the isolation among the patches is greatly increased. The overall miniaturized dimension of the MIMO antenna is 25 × 40 mm². The edge-edge spacing among the elements is 0.0233λ. The prototype antenna is fabricated and measured that shows good agreement compared with simulated results. The designed MIMO antenna without the presence of decoupling structure offers an isolation of 28 dB, gain of 3.6 dBi, and radiation efficiency of 69.7% at the resonant frequency. The proposed MIMO antenna covers a broad range of frequency band from 3.296 to 5.962 GHz with −10 dB impedance bandwidth of 2666 MHz and maintains a good isolation of greater than 50 dB for the entire operating band. The tested radiation efficiency and gain are 85.3% and 6.22 dBi at 3.5 GHz. Moreover, the diversity parameters of the neutralization line integrated MIMO antenna, that is, channel capacity loss (CCL) isolation, mean effective gain (MEG), total active reflection coefficient (TARC) diversity gain (DG), and envelope correlation coefficient (ECC), are analyzed and discussed in this article.     

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.

     

手持终端波束成形天线阵列的优化设计

设计了一款适用于移动手持终端的低剖面波束成形天线阵列。该天线阵列由八个结构相同的倒F天线组成,可以工作在GSM1900(1880~1920 MHz)、LTE2300(2300~2400 MHz)和LTE2500(2540~2620 MHz)三个频段。通过功率传输效率最大化理论,可以优化出该阵列在所需方向上的最佳激励。通过馈电电路板给8个天线单元提供优化的激励,可以将天线波束偏转到所需方向,并且保证天线在该方向上获得最大可能增益。天线阵列工作在2.45 GHz时,在x、y、z方向上的增益分别为7.80、6.03和7.20 dBi;相应地,在1.9 GHz时分别为6.67、5.27和6.05 dBi。     

A New Compact Microstrip-Fed Dual-Band Coplanar Antenna for WLAN Applications

A novel compact microstrip fed dual-band coplanar antenna for wireless local area network is presented. The antenna comprises of a rectangular center strip and two lateral strips printed on a dielectric substrate and excited using a 50 Omega microstrip transmission line. The antenna generates two separate resonant modes to cover 2.4/5.2/5.8 GHz WLAN bands. Lower resonant mode of the antenna has an impedance bandwidth (2:1 VSWR) of 330 MHz (2190-2520 MHz), which easily covers the required bandwidth of the 2.4 GHz WLAN, and the upper resonant mode has a bandwidth of 1.23 GHz (4849-6070 MHz), covering 5.2/5.8 GHz WLAN bands. The proposed antenna occupy an area of 217 mm² when printed on FR4 substrate (epsiv_r=4.7). A rigorous experimental study has been conducted to confirm the characteristics of the antenna. Design equations for the proposed antenna are also developed     

A compact wide slot antenna with dual band-notch characteristic for ultra-wideband applications

A new type of ultra-wideband (UWB) antenna with a dual-notched frequency band, compact size of 21?×?28?mm² and a coplanar waveguide (CPW) fed is proposed in this article. Two notched frequency bands are obtained by embedding two U-shaped slots in the radiation patch and a rectangle slot in the ground plane, which can be controlled by adjusting the length of the responding slots. The frequency domain characteristics are investigated and measured. Both the experimental and numerical results show that the proposed antenna has an impedance bandwidth ranging from 3.1?GHz to more than 11.0?GHz in which voltage standing wave ratio is less than 2, expect two notch frequency band, 5–6?GHz (WLAN) and 7.7–8.5?GHz (X-band for satellite communications in China).     

Low profile multiband rectenna for efficient energy harvesting at microwave frequencies

This paper presents the design and development of a multiband rectenna for ambient RF energy harvesting. The proposed rectifying antenna consists of fractal-based geometry to obtain GSM 0.9 GHz (0.8–1.2 GHz), GSM 1.8 GHz (1.6–2.1 GHz), WLAN 2.5 GHz (2.2–2.8 GHz), Wi-MAX 3.5 GHz (3.1–4.0 GHz), WLAN 5.5 GHz (5.3–6.4 GHz) and 7.35 GHz (7.0–7.8 GHz) resonating bands. The designed sensing antenna is low profile, lightweight and small in size with two circularly polarized bands at frequencies 1.8 and 2.5 GHz. In the proposed rectenna, a dual-stage voltage doubler rectifying circuit is utilized for converting surrounding RF signals into DC power. A matching network is connected between the fractal antenna and the rectifying circuitry for realizing a good impedance matching between them. To verify the proposed design, a prototype rectenna is fabricated and measured results are compared with the simulated results. The proposed rectifier provides an RF to DC conversion efficiency of 78%.     

一种适用于GSM DCS和ISM频段的PIFA天线

移动通信业务的多样化要求多种业务共用一副天线,以节省终端内的有限空间。在平面倒F天线(PIFA)的基础上加载一种新型的缝隙结构,得到一种适用于GSM900、DCS1800和ISMWLAN2.4GHz三个频段的小型宽带移动终端天线。仿真结果表明,该天线在三个频段上的相对阻抗带宽分别达到6.5%、7.5%和3.4%,尤其是在GSM900MHz频段的阻抗带宽比其他同类型天线展宽1倍。该天线具有较好的频率特性和辐射特性,完全适合多频移动通信终端应用。     

Small Internal Antenna Using Multiband,Wideband, and High‐Isolation MIMO Techniques

In this paper, a small internal antenna for a mobile handset is presented using multiband, wideband, and high‐isolation multiple‐input multiple‐output techniques. The proposed antenna consists of three planar inverted‐F antennas (PIFAs) that operate in the global system for mobile communication (GSM900), the digital communication system (DCS), the personal communication system (PCS), the universal mobile telecommunication system (UMTS), and wireless local area network (WLAN) bands with a physical size of 40 mm × 10 mm × 10 mm. A resonator attached to the folded PIFA creates dual resonances, achieving a wide bandwidth of approximately 460 MHz, covering the DCS, PCS, and UMTS bands; a meander shorting line is used to improve impedance matching. Additionally, a modified neutralization link is embedded between diversity antennas to enhance isolation, which results in a 6‐dB improvement in the isolation and less than 0.1 in the envelope correlation coefficient evaluated from the far‐field radiation patterns. Simulation and measurements demonstrate very similar results for S‐parameters and radiation patterns. Peak gains show 3.73 dBi, 3.77 dBi, 3.28 dBi, 2.15 dBi, and 5.86 dBi, and antenna efficiencies show 56.15%, 72.15%, 68.59%, 52.92%, and 82.93% for GSM900, DCS, PCS, UMTS, and WLAN bands, respectively.     

ACS-Fed e-Shaped Dual Band Uniplanar Printed Antenna for Modern Wireless Communication Applications

A printed small size (12×16.5 mm) ACS-fed e-shaped uniplanar antenna is proposed for dual band applications. The multiband operating characteristics have been achieved by integrating e-shaped radiating strips to the 50ΩACSfeed line. Two simultaneously operating wide bands have been generated by using optimized radiating branch strips for the multiband applications. For obtaining size reduction and wider impedance bandwidth, e-shaped meandered elements are chosen in the design. The proposed design features the bandwidth (VSWR < 2, reflection coefficient below–10 dB) of 100 MHz in 2.4–2.5 GHz, and 2100MHzin 4.0–6.1 GHz. The developed multiband antenna can be useful for several wireless communication applications, such as 2.4 GHz Bluetooth/RFID,WLAN(2.4/5.2/5.8 GHz), WiMAX (5.5 GHz), US public safety band (4.9 GHz), ISM band, radio frequency energy harvesting and internet of things (IoT) applications.     

A slot resonators based quintuple band-notched Y-shaped planar monopole ultra-wideband antenna

A Y-shaped ultra-wideband (UWB) monopole antenna containing modified ground plane with five stop bands is presented. An inverted U-shaped slot and a C-shaped slot are placed on Y-shaped radiating patch to achieve two notched bands while three pairs of C-shaped slots are placed at different positions on modified ground plane to achieve three more notched bands. The proposed antenna is designed, fabricated and experimentally tested. The designed Y-shaped antenna has overall dimensions of 36 × 38 × 1.6 mm³ (0.34λ_l × 0.36 λ_l × 0.016 λ_l) and has impedance bandwidth 2.86–13.3 GHz at |S₁₁| < −10 dB level. Measured band notches are achieved at 3.75/5.43/7.87/8.62/9.87 GHz centre notched frequencies to eliminate worldwide interoperability for microwave access (WiMAX) band (3.45–4.0 GHz), wireless local area network (WLAN) band (5.15–5.90 GHz), X-band for satellite communication (6.77–8.00 GHz), ITU-8 band (8.3–9.1 GHz), and radio navigation (RN) band (9.3–10.6 GHz), respectively. Variation of slot parameter on individual band notch is also investigated. Omnidirectional radiation pattern for XZ-plane and dipole-like radiation pattern for YZ-plane are observed. Stable gain, variation of phase response in linear fashion and group delay <1.3 ns for whole ultra-wideband except at band notches is achieved.