一种应用于微波探测的双频天线的设计

为增加火灾探测天线频带范围,基于微带贴片天线,采用凹槽加载技术,设计了中心频率在Ku(12.4～18.0 GHz)波段的双频微带单元天线.利用HFSS软件对其建模、仿真及优化,结果表明,该单元天线在14.8 GHz和16.1 GHz时回波损失达到最小值,且回波损失小于-10 dB的带宽分别为600MHz和390 MHz.利用该单元天线,进而设计了一款2×2阵列天线,实测结果表明:该阵列天线具有很好的双频谐振特性,在14.3～14.9 GHz和15.7 ～16.1 GHz频带内既保留了原单元天线好的回波损耗特性,又提高了增益,使两个频段最大增益分别达到13.7 dBi和11.3 dBi.     

一种微带天线RCS减缩方法研究

针对微带天线辐射性能提高和RCS减缩这一矛盾,寻求一种对辐射性能影响较小的微带天线RCS减缩新方案.分析了几种RCS减缩方法对微带天线辐射性能及其散射特性的影响,给出了一种综合利用微带贴片上缝隙加载、短路针加载及接地板开缝的微带天线RCS减缩新方法.实现了在天线的工作频率保持不变,增益、带宽损失很小的情况下.微带天线RCS在较宽的频带内得到较大幅度的减缩.仿真实验表明该综合方法是一种较好RCS减缩方法,对微带天线隐身技术有重要的借鉴作用.     

基于缝隙耦合的微带天线设计

能够同时适用于射频识别、全球微波无线互联网和无线局域网这几大主流物联网通信技术标准的宽频天线的设计要求越来越高,比如体积小、成本低等,而微带天线体积小、剖面低且可集成化程度高,适合大批量生产,但其频带较窄,使用范围受到限制。为此,提出了一种紧凑型宽频带微带贴片天线。该天线引入了L型缝隙和三角形缝隙,仿真结果表明,天线-10 dB阻抗带宽可达到100%,其工作频带为1. 5 GHz～4. 3 GHz;轴比带宽为3. 4 GHz～3. 8 GHz,圆极化带宽为11%;在该范围内的增益都在3 dB以上;整个工作频带范围内都实现了宽频带、高增益等特性,适用于射频识别、蓝牙、WLAN等频段。     

一种宽频带四单元微带天线阵设计*

综合运用了H型缝隙耦合馈电技术和引入空气层技术展宽了天线的频带,设计出一个工作在Ku波段的宽频带微带天线单元并组成四单元阵列。该天线由两层介质板构成,并利用180°反相馈电抑制了高次模的耦合激励,降低了交叉极化电平。使用三维电磁场仿真软件(Ansoft HFSS)对微带天线进行仿真优化,仿真结果表明,天线单元性能良好,相对阻抗带宽(S11≤-10 dB)为8.5%,增益为8.05 dB。四单元天线阵列相对阻抗带宽(S11≤-10 dB)达到16.6%,增益为13.7 dB。天线阵列性能良好,设计方法具有很好的可扩展性。归纳总结出的介电常数计算式也具有普遍性。     

一种用于FOD检测系统的V波段波导缝隙阵列天线

提出了一种适用于跑道异物（Foreign Object Debris, FOD）检测系统的V波段波导缝隙阵列天线。所提出的阵列天线工作频带为74～79 GHz,阵面包含2 048个单元。天线采用多模波导缝隙阵列天线形式,并设计了波导功分网络,具有高增益、低剖面等优良特点。天线整体结构厚度10 mm以内,辐射效率50%以上。天线的实测结果表明,理论结果和测试结果吻合,具有较高的工程实用性。     

一种新型EBG低剖面的微带基站天线设计

设计了一种工作在LTE及5G频段的新型微带基站天线,该天线通过在反射背板上加载新型EBG的方法,既满足天线的工作带宽及辐射增益,还达到了降低天线剖面高度的作用,将天线的高度从40 mm降低至22 mm。该基站天线的工作频带为1.65～3 GHz,阻抗带宽达到了1.351 GHz,阻抗带宽达到58%,在2.1 GHz频率上天线的方向性系数为8.13 dBi。研究证明,贴片在反射背板上加载EBG结构可以有效降低天线高度。     

一种宽频带复合天线设计

针对多系统载体天线数量多的问题,提出了一种基于印刷振子结构的宽频带共口径复合天线设计方法;通过两种不同形式的印刷偶极子进行共口径设计：采用平面印刷偶极子结构完成宽带高增益线极化天线,通过宽带定向耦合器实现了天线和差方向图辐射;采用十字印刷偶极子实现低增益天线的圆极化辐射;两种天线单元印刷在同一微波介质上,通过优化天线单元布局,相对位置关系和增加金属隔离环等措施,降低天线之间的相互影响,实现共口径复合天线性能满足工程应用要求;加工了天线样机,测试结果表明线极化天线在工作频带1.2～1.8 GHz范围内和差通道电压驻波比小于1.8,和通道增益大于13.5 dBi,方位差波束零值深度小于-25 dB,圆极化天线在工作频带1.2～1.8 GHz范围内电压驻波比小于1.6,增益大于6.5 dBi,轴比小于2.5 dB,与计算结果基本一致;复合天线可以满足多种无线通信系统的需求,减少了天线数量,有效节省载体平台空间,同时具有结构简单紧凑、剖面低、易于工程实现等特点,具有广阔的应用前景。     

一种具有双陷波特性单极子超宽带天线的设计

提出了一种基于C/U形槽、具有双陷波特性的平面超宽带单极子印制天线。其天线的组成部分包括椭圆球拍形辐射贴片、微带馈电线和矩形地板。通过在球拍形辐射贴片蚀刻C形槽、馈电线蚀刻U形槽的方法,使天线在WiMAX(3.3~3.7GHz)和WLAN(5.15~5.825GHz)频段内具有双陷波性能。仿真和测量结果表明,这种新型天线在通频带(2.5~10.6GHz)内电压驻波比小于2,在2.9~3.9GHz和4.9~6.0GHz两个频段内电压驻波比大于5,阻带的频率可通过蚀刻槽的长、宽来调节。该天线的测试结果与仿真结果吻合良好,且尺寸小巧、结构简单、成本低,可应用于超宽带通信系统。     

应用于WSN的小型化微带天线的研究

基于目前对WSN(无线传感器网络)的需求,本文设计了一种工作在2.4GHz的小型化的矩形开槽微带贴片天线,由于采用了曲流技术,该天线比一般微带天线要小,当工作在2.4GHz时,其导波波长为70mm,天线尺寸为29mm×29mm,长宽均为导波波长的0.4倍。仿真与测试结果表明,实验结果与仿真结果基本吻合。天线的-10dB带宽为24MHz(2.38GHz-2.404GHz),天线的辐射特性较好,在-10dB带宽内,辐射增益均大于0dBi,而且在中心频率2.4GHz处达到最大值6dBi。     

一种宽频带单臂螺旋天线的设计

设计一种带反射腔的宽频带单臂螺旋天线,在反射系数S11<-10 dB标准下,频带范围为0.686GHz-3.15 GHz,天线结构尺寸为半径59.5 mm,厚度3.2 mm。相比于传统的平面螺旋天线,该天线结构紧凑、不需要巴伦、加工制作简单方便,适合于有宽频带圆极化应用需求的电子设备。     

A wideband circularly polarized antenna array with sequential rotation feed

A novel wideband circularly polarized (CP) antenna array is designed, which consists of a horizontally placed wideband phase shifting feed network and four vertically placed linearly polarized dipole antenna elements, and the circular polarization is realized based on sequential rotation feeding technology. By placing two parasitic strips and two grounding strips on the top and side of each T‐shaped dipole antenna element, the impedance bandwidth and circular polarization performance of the antenna can be further improved. The simulation results show that the 10‐dB impedance bandwidth of the antenna is 93% (1.56‐4.27 GHz) and the 3‐dB AR bandwidth is 80.7% (1.7‐4.0 GHz). The measured results are in good agreement with the simulation results. Due to the use of orthogonally placed wideband feed network and wideband array elements, the proposed antenna array has a wider circular polarization bandwidth than the similar antenna arrays reported.     

Microstrip patch antenna feed for offset reflector antenna for dual band application

In this article, details of a dual band microstrip patch antenna (MPA) array feed for an offset reflector antenna is presented. The main objective of the proposed structure is to achieve low cross‐polarization at Φ = 90° plane in the reflector pattern. Low cross‐polar levels in the reflector pattern are achieved by illuminating the reflector with fields of the proposed dual band feed structure. A centered circular array as the dual band feed structure is proposed in which the central radiating element is a dual mode circular MPA operating at 6 GHz and the surrounding circular ring of eight circular MPA elements operating at 4 GHz in the dominant mode. The dual mode central antenna uses the concept of conjugate field matching for cross‐polarization reduction. TM₂₁ mode is excited at an appropriate ratio with the TM₁₁ mode to achieve the proper field matching at 6 GHz. The radius of the surrounding circular array is varied to obtain cross‐polarization better than ?30 dB at both the resonant frequencies. The offset reflector gain is found to be better than 37 dB with a 2.5 m parabolic reflector and F/D = 0.8 at both the operating frequencies.     

Dual‐polarized textile‐based two/four element MIMO antenna with improved isolation for dual wideband application

This article presents the designs of dual‐polarized dual wideband textile‐based two and four elements multiple‐input multiple‐output (MIMO) antennas for WLAN (IEEE 802.11a/b/g/c/n) and WiMAX (IEEE 802.16d) applications. These MIMO antennas cover the frequency spectra from 1.5 to 3.8 GHz (87% bandwidth) and 4.1 to 6.1 GHz (40% bandwidth). The characterization of the textile jeans substrate is determined experimentally using a vector network analyzer and dielectric assessment kit. These antennas provide near about 70% radiation efficiency with around 4 dBi peak gain in desired frequency ranges. The diversity performance is improved noticeably by printing meandered line structures on both planes. The proposed MIMO structure has a very low envelop correlation coefficient (ECC) <0.1 and high diversity gain (DG) >9.9. The Medium effective gain (MEG) also lies within a satisfactory value of ±3 dB. The two elements MIMO Antennas provide linear polarization at all desired frequency band while the four‐element antenna provides circular polarization at 2.4 GHz and linear polarization at 5.2 and 5.8 GHz application bands. The antenna also depicts good performance in wearable condition with safe specific absorption rate < 1.6 W/kg in all desired frequencies.     

Wideband cavity‐backed log‐periodic‐slot end‐fire antenna with vertical polarization for conformal application

A 6–18 GHz wideband cavity‐backed log‐periodic‐slot end‐fire antenna with vertical polarization for conformal application is presented. The log‐periodic folded slots and parasitic slots with 10 slot elements are applied to cover 6–18 GHz frequency band and the log‐periodic metallic cavity is placed under each slot element to keep wideband performance and prevent the effects of large metallic carrier on radiation patterns. The ground plane etched with log‐periodic slots is reversed and touched directly to the backed cavity and a dielectric cover is added to the antenna, to further improve the antenna performance. Meanwhile, a broadband microstrip‐coplanar waveguide transition is inserted in the antenna for measurements. With these designs, the proposed antenna shows good impedance matching (|S₁₁|<27 dB) and end‐fire gain (>4 dBi) performances in 6–18 GHz. The proposed antenna also keeps low‐profile and easy flush‐mounted characteristic which is suitable for conformal applications of high speed moving carriers.     

Design of hexagonal circularly polarized antenna array using paralleled dynamic minimum lower confidence bound

This article presents a hexagonal circularly polarized microstrip antenna (HCPMA) array design using paralleled dynamic minimum lower confidence bound. The HCPMA array is fed by a hybrid feeding network composed with “H” type apertures coupling network and 45° slots which are loaded on the hexagonal patch. It is designed to be compatible with ISM band which achieves a 2.56 GHz impedance bandwidth (S11<–10 dB) and a 0.6 GHz Axial ratio (AR) bandwidth (AR < 3 dB). Given the heavy computational burden and limited computation resources of the electromagnetic analysis, the improved algorithm using MLCB in conjunction with paralleled finite element model and Kriging metamodel achieves two times speed enhancement for the antenna optimization than the traditional MLCB optimization. The multi‐objective optimization is introduced to solve the polarization, impedance, and radiation pattern of the HCPMA element and array. The antenna optimization results show that the proposed strategy can not only obtain an optimal solution, but also significantly improve the calculating efficiency.     

Low‐profile omnidirectional circularly polarized antenna based on substrate integrated waveguide technology

A substrate integrated waveguide (SIW) circularly polarized (CP) antenna with omnidirectional radiation in the azimuthal plane is proposed. The antenna consists of five identical end‐fire CP antenna elements in a pentagonal array configuration, which is loaded on a circular substrate. Each element contains an H‐plane horn antenna in SIW structure and a printed dipole antenna. Five parasitic curve elements are introduced to improve the omnidirectional property of the antenna. Combined with complementary dipoles theory and SIW technology, prototype antenna is designed, fabricated and measured. With a low profile of 0.024λ₀, the antenna has a 10‐dB return‐loss impedance bandwidth of 4.08% (2.4～2.5 GHz) and a 3‐dB axial‐ratio (AR) bandwidth of 5.76% (2.36～2.50 GHz). The antenna works well in the 2.45 GHz ISM band, with good cross‐polarization and excellent omnidirectional property.     

High gain flexible liquid crystal polymer based 8‐element printed antenna for millimetric wave applications

In this article, an offset fed printed dipole antenna 2‐element, 4‐element, and 8‐element arrays are developed and analyzed for millimeter wave applications. The 8‐element array antenna is of compact size with dimensions 43.6 × 25.1 × 0.25 mm³. It achieved a broad impedance bandwidth (S₁₁ < ?10 dB) of 15.7 GHz from 24.7 to 40.4 GHz. The mutual coupling between array elements is less than ?35 dB in the operating band. The antenna achieved a gain of 12.62 to 13.1 dB. The 8‐element array antenna is fabricated on liquid crystal polymer material and tested. Impedance matching, far field radiation characteristics, co‐polarized and cross‐polarized patterns and group delay are analyzed in simulation and experimental measurement. The investigated results are in good agreement and hence, the developed array antenna is attractive for wideband millimeter wave applications.     

A high gain wideband circularly polarized antenna with asymmetric metasurface

An asymmetric‐metasurface based wideband circularly polarized (CP) microstrip antenna using a coaxial probe is proposed for L‐band applications. The antenna involves a stacked asymmetric‐metasurface, a radiating rectangular‐patch and a coaxial feed. An asymmetric‐metasurface is designed using rectangular unit cells and smaller size unit cells along one of the diagonal lines. The asymmetric‐metasurface is placed above a radiating rectangular‐patch with support of foam layer to achieve a wideband CP radiation. The measured performance of the prototype antenna achieves an impedance bandwidth (?10 dB return loss bandwidth) of 15.7% (1.58‐1.85 GHz) with CP bandwidth (3‐dB axial ratio) of 13% (1.58‐1.80 GHz) and gain of ≥9 dBic.     

一种高增益宽频带圆极化微带阵列天线的研制

针对微带天线阻抗匹配带宽一般较窄的自身缺陷,基于相控阵雷达天线的应用背景,设计了一种工作在X波段的双层圆极化微带天线结构,且优化发现,其各电磁参数良好。为提高其增益,还在此基础上设计并最终制作了双层2×2结构的微带天线阵列,其实测性能与设计值相符,增益达到10.7dB,带宽1.2GHz,相应轴比为4dB,符合圆极化要求。     

Design and evaluation of a wideband reflectarray antenna using cross dipole with double‐ring elements

This article reports the design and analysis of a wideband, single layer, and dual‐polarized microstrip reflectarray for Ku‐band applications. The array element is constructed using a crossed dipole enclosed by two cross dipole loops. The element is optimized to exhibit a linear phase response and wide reflection phase range. The reflection characteristic of the unit cell is analyzed using an infinite array approach and the results are presented. A 324‐element Ku‐band microstrip reflectarray antenna of size 20 × 20 cm² is simulated, fabricated, and experimentally evaluated. The 2.9‐dB gain‐bandwidth and aperture efficiency of the reported reflectarray are 45.3% and 35%, respectively. The reflectarray operates in the frequency range of 10.6 to 16.8 GHz.