Equivalent circuit model-based design and analysis of microstrip line fed electrically small patch antenna for sub-6 GHz 5G applications

In this paper, an equivalent circuit model-based electrically small patch antenna is designed for sub-6 GHz 5G application (3.5 GHz) using 50-Ω microstrip line feed. The overall size of the proposed antenna is 0.33λ₀ × 0.4λ₀ × 0.019λ₀ (28 × 34 × 1.6 mm³) at 3.50 GHz frequency. The proposed antenna has a tilted Y-shape slot, two rectangular shape slots, and two rectangular shape notches in the radiating patch. The proposed antenna is resonating from 3.21 to 3.74 GHz covering the entire sub-6 GHz 5G band (3.3–3.8 GHz). The impedance bandwidth (simulated) of the proposed antenna has been obtained 530 MHz resonating at 3.50 GHz frequency. The good return loss of −23.62 dB is also obtained at 3.50 GHz resonant frequency. The simulation results and geometry of the proposed antenna are validated with equivalent circuit model and experimental measurement of prototype antenna using vector network analyzer (VNA) and anechoic chamber. In the whole operating frequency range, the measured findings show reasonable agreement with the simulated ones. The measured impedance bandwidth of the proposed antenna has been obtained 480 MHz (3.21–3.69 GHz) resonating at 3.48 GHz frequency with a return loss of −21.61 dB, while the theoretical impedance bandwidth of the proposed antenna has been obtained 720 MHz (3.18–3.90 GHz) resonating at 3.58 GHz frequency with a return loss of −21.5 dB. The peak gain of 3.39 (simulated) and 3.2 dB (measured) is obtained at 3.50 GHz frequency. Moreover, the antenna shows 97% (simulated) and 95% (measured) efficiency at 3.50 GHz frequency.     

一种新型圆极化UHF通用型RFID读写器天线

面向超高频(UHF)通用型射频识别(RFID)读写器天线的应用需求,设计了一款完全覆盖全球UHF(840-960MHz)频段的RFID圆极化读写器天线。天线采用平面缝隙贴片结构,以共面波导(CPW)馈电方式实现宽频带圆极化特性。测试结果表明,天线的阻抗带宽为735-1014MHz(S11<-10dB),相对带宽31.9%,并且在840-960MHz频段内S11<-20dB,3dB轴比带宽为838-1134MHz,相对带宽30.0%,工作频带内有大于3.5dBi的平坦增益。仿真结果与测试结果基本吻合,天线结构精简,易于加工,满足全球UHF RFID读写器天线的应用需求。     

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.     

Indirect coupling method for RFID tag antenna design

Proposed is an indirect coupling method for designing an RFID tag antenna, which can not only achieve broadband operation, but can also conveniently implement a complex conjugate impedance match between an antenna and an RFID chip. An equivalent circuit model of the proposed coupling method is presented to characterise the performance of the antenna. An example is included to demonstrate the coupling method for an antenna with half-power bandwidth of approximately 16% (840-985 MHz), and which covers the entire UHF RFID frequency band. Estimated and simulated results are shown to be in good agreement with measured ones.     

A narrow-frame antenna for WWAN/LTE/WiMAX/WLAN mobile phones

In this paper, we present a novel narrow-frame antenna with a size of 75 × 8 × 5.8 mm³ for 5.7 in. mobile phones. The antenna mainly consists of a monopole with four branches that are coupled to a two-branch grounded strip. Our antenna is able to cover more bands than other narrow-frame antennas by excitation of several resonant modes. The improved range of the antenna covers the following eleven bands: LTE700, GSM850, GSM900, DCS, PCS, UMTS, LTE2300, LTE2500, LTE3400 (3400–3800 MHz)/WiMAX3.5 GHz (3400–3650 MHz), WLAN5.2 GHz (5150–5350 MHz) and WLAN5.8 GHz (5725–5875 MHz). Another advantage of the proposed antenna is that it does not need any lumped element to match the antenna. The working principles of the proposed antenna are thoroughly studied. A prototype of the proposed antenna is fabricated and measured, with the results in good agreement with the simulation results.     

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.     

一种超高频射频识别读写器天线

本文提出了一种适用于我国UHF RFID读写器的宽带圆极化叠层微带天线,通过选用廉价FR4板、空气层介质和对角线切角的正方形贴片组成叠层结构,采用S型水平蜿蜒带条激励主辐射贴片的馈电方式,展宽了天线的阻抗带宽和轴比带宽.所提出的S型水平蜿蜒带条馈电技术,实现了对称的辐射方向性图.给出了天线设计思路,并利用电磁仿真软件分...     

一种新型UHF RFID阅读器圆极化天线

传统的圆极化阅读器天线采用单馈电微带天线方式设计,频带窄、极化特性较差。在单馈电微带天线的基础上,采用探针馈电曲线贴片的方式,在圆形铁片上开了4个对称的方形缝隙,最终设计出一种新型的UHF RFID圆极化阅读器天线。天线的结构尺寸为167.5 mm×167.5 mm×3 mm,阻抗带宽为870~936 MHz,3 dB轴比带宽为900~918 MHz,最大增益为3.5 dB。与传统的圆极化阅读器天线相比,设计的天线频带宽,且极化特性得到良好改善,能够满足工程上的应用需求。     

一种面向卷烟包装新型超高频rfid标签天线设计

本文设计了一种新型的抗金属无源UHF射频识别(RFID)印刷标签天线.该天线可以应用在卷烟包装上,仿真和实测数据证明,在915MHz处天线的阻抗为(20+j149)Ω,能和Alien Higgs -2芯片很好的实现共轭匹配.该标签天线的工作带宽为31MHz,通过RFID阅读器实测表明,所设计的标签天线读取距离可达到0.8m.     

超高频RFID小型化读写器天线设计

提出了一款应用于超高频段(Ultra High Frequency,UHF)(912 ~935 MHz)的射频识别(RFID)读写器圆极化单层结构微带天线,基板采用FR4 板材达到价格低廉、辐射贴片采用开槽的结构实现小型化、接地板采用开槽结构提高天线的增益,该天线实现了小型化设计,满足了天线的设计要求。利用三维电磁仿真软件对天线模型进行了分析,仿真与测试结果吻合良好。天线测试结果表明:回波损耗小于-10 dB 的阻抗带宽为25 Hz(910 ~ 935 MHz),轴比(AR)小于3 dB的带宽为21 MHz(914 ~935 MHz);在UHF 频段内,读写器天线的最大增益为-1.2 dB,所以本天线能满足我国射频识别读写器的应用要求,具有良好的应用前景。     

Design of a wideband Y-shaped antenna for the application in IoT and 5G communication

A small wideband Y-shaped antenna is presented in this paper. A monopole of Y-shaped with two rectangular-shape frequency shifting strip is used to produce a compact dimension of 10 mm × 12 mm on a 1-mm-thick FR4 substrate. The antenna has an impedance bandwidth (measured below ?10 dB from 39.57 to 44.63 GHz), a gain more than 4.9 dB, radiation efficiency of 81%, and voltage standing wave ratio (VSWR) < 2, within the bandwidth of interest, making it a viable option for 5G applications. The use of a (01.7850 × 2.6775 × 00.02) mm³ metallic strip located above the feed line is also shown to efficiently increase the antenna bandwidth to values greater than 5 GHz without affecting the other antenna parameters. Additionally, the measured results in comparison with the simulated results reveal negligible changes, confirming that the proposed antenna is also suitable for the applications of 5G with Internet of Things.     

A dual-band semi-circular patch antenna for WiMAX and WiFi-5/6 applications

A semi-circular patch antenna (SCPA) is designed for WiMAX and WiFi-5/6 communications. The footprint of the proposed SCPA is only 30 × 40 × 1.575 mm³, which is composed of a semi-circular patch and a partial ground plane. The main strength of this work is that the estimated wide dual-frequency span of 2.39–3.75 GHz and 5.39–7.18 GHz are contributed with two sharp resonances at 2.77 and 6.46 GHz, respectively. The proposed SCPA has been practically tested after fabrication. The measured results confirm that the designed antenna achieved the bandwidth necessity for WiMAX 1.5 (2.5–2.69 GHz), WiMAX 2 (3.4–3.6 GHz), WiFi-5 (5.15–5.85 GHz) and WiFi-6 (5.925–7.125 GHz). In the two resonance frequencies of 2.77 and 6.46 GHz, the designed antenna achieved a gain of 2.558 and 4.109 dB, respectively. In addition, the SCPA also manifests good radiation properties and achieves an average efficiency of more than 90%. A professional version of the 3D electromagnetic simulator is utilized to examine the effect of diffident parameters and model the tested antenna.     

基于二元偶极子阵的边射端射可重构RFID阅读器天线设计

基于射频识别应用场景中存在的一些T型结构，如楼内、地下矿井等存在的一些T型通道，为做好这些场景中的信号覆盖，本文提出了一种新颖的边射端射可重构的RFID阅读器天线。天线由可重构的馈电网络和两个相距半波长的偶极子组成，天线边射和双向端射的可重构特性通过控制馈电网络中的开关状态实现。为了验证天线性能，对其进行了加工测试。测试结果表明，天线在边射和端射状态下的阻抗带宽和增益分别为2.7%(900～925 MHz),4.15 dBi和1.9%(905～923 MHz),2.10 dBi,与仿真结果基本一致。该天线具有结构简单、小型化、低剖面等优势，在射频识别系统中有一定的应用价值。     

A new wideband planar antenna with band-notch functionality at GPS,Bluetooth and WiFi bands for integration in portable wireless systems

Empirical results are presented for a novel miniature planar antenna that operates over a wide bandwidth (500 MHz to 3.05G Hz). The antenna consists of dual-square radiating patches separated by two narrow vertical stubs to reject interferences from GPS, Bluetooth and WiFi bands. Radiating patches and stubs are surrounded by a ground-plane conductor, and the antenna is fed through a common coplanar waveguide transmission line (CPW-TL). The two vertical stubs generate pass-band resonances enabling wideband operation across the following communications standards: cellular, APMS, JCDMA, GSM, DCS, PCS, KPCS, IMT-2000, WCDMA, UMTS and WiMAX. Embedded in the ground-plane conductor is an H-shaped dielectric slit, which has been rotated by 90°, whose function is to reject interferences from GPS, Bluetooth and WiFi bands. Measurements results confirm the antenna exhibits notched characteristics at frequency bands of GPS (1574.4–1576.4 MHz), Bluetooth (2402–2480 MHz) and WiFi (2412–2483.5 MHz). The impedance bandwidth of the antenna is 2.55G Hz for VSWR < 2, which corresponds to a fractional bandwidth of 143.66%. Measured results also confirm that the antenna radiates omnidirectionally in the E-plane with appreciable gain performance over its operating frequency range. The antenna has dimensions of 15 × 15 × 0.8 mm³.     

Shorted Microstrip Patch Antenna Using Inductively Coupled Feed for UHF RFID Tag

A very small patch‐type RFID tag antenna (UHF band) using ceramic material mountable on metallic surfaces is presented. The size of the proposed tag is 25 mm×25 mm×3 mm. The impedance of the antenna can be easily matched to the tag chip impedance by adjusting the size of the shorting plate of the patch and the size of the feeding loop. The measured maximum reading distance of the tag at 910 MHz was 5 m when it was mounted on a 400 mm × 400 mm metallic surface. The proposed design is verified by simulation and measurements which show good agreement.     

一种共面波导馈电的圆极化天线的设计

RFID系统在当今社会应用广泛,天线在RFID系统中的作用尤其重要,圆极化天线的设计大大提高了系统的灵活性和可靠性。给出了一款通用频带的特高频RFID 阅读器天线。该天线通过共面波导馈电,在介质层顶部的接地平面刻蚀方形槽,为了增加天线阻抗带宽,将共面波导馈线弯折设计;为了提升天线的圆极化性能,在槽内适当添加L 型连接线。该天线实现了410 MHz的阻抗带宽和488 MHz的轴比带宽,天线尺寸为115 mm*115 mm*0.3 mm。     

On the behaviour of a compact antenna system with non-resonant elements in the presence of the human head

A novel handset antenna technique to solve the increasing demand of mobile bands, the loading effects (mismatching and efficiency losses) and the power absorption introduced by the head is analysed in terms of bandwidth, efficiency and SAR (specific absorption rate). The technique proposed integrates non-resonant elements and its results are compared with those obtained by a planar inverted-F antenna. The main antenna parameters (bandwidth, efficiency in free-space, efficiency regarding the human head presence and SAR) are compared in terms of electromagnetic simulation and measurements. The study concludes that the novel antenna architecture achieves multiband operation from 824–960 MHz and 1710–2170 MHz and become robust to human loading while occupying a reduced volume of just 250 mm³ in a typical handset phone.     

A Compact Plus Shaped Carpet Fractal Antenna with an I-Shaped DGS for C-band/X-band/UWB/WIBAN applications

This article presents the design and development of a compact broadband “+” shaped aperture coupled carpet fractal antenna with a defected ground structure (I shaped slot in the ground) for broadband/ultra wideband (UWB) and a multiband characteristics. The antenna has overall dimensions of 8.4 cm?×?5.5 cm?×?3.2 mm and is fed using aperture coupled feeding mechanism. It shows an impedance bandwidth (<?10 dB) of 4460 MHz from 6.93 to 11.39 GHz with fractional bandwidth of 0.48 at the center resonant frequency of 9.16 GHz. A multiband behavior is also exhibited by this antenna from 3.9–4.08 GHz, 4.8–5.06 GHz and 6.1–6.4 GHz with impedance bandwidths of 180 MHz, 260 MHz and 300 MHz respectively. It therefore supports the wireless applications of Wi-MAX (3.8–4.1 GHz), Wi-BAN/long distance radio telecommunication (4.8–5.06 GHz), wireless sensor networks (6.1–6.4 GHz), satellite (7.4–7.8 GHz) and UWB (6.9–11.03 GHz). The antenna is designed as a ‘+’ shaped patch with fractal rectangular slots cut out from it up to iterations of second order that allow the antenna to support multiband characteristics. The bandwidth at these bands is improved by using I shaped defected ground structure (DGS) and a parasitic feeding method i.e. aperture coupled feeding (Karur et al., in: ICMARS (IEEE), Jodhpur, India, pp. 266–270, 2014).The antenna has a compact structure with two layers of FR4 substrate, the ‘+’ shaped carpet fractal printed on the upper substrate layer and the lower substrate has a ground layer printed on its top and feed line on its bottom layer respectively. It shows a simulated peak gain of 4 dB at an operation frequency of 7.95 GHz. The antenna design and simulations are done using CST MWS V14. The Simulation results in terms of impedance bandwidth, smith chart, gain are presented in this article. To validate the impedance bandwidth results, the proposed carpet fractal antenna is experimentally tested using a vector network analyzer and the measured results are found to be closely matching with the simulated ones, allowing the antenna to be practically suitable for the afore mentioned wireless applications.

     

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.