面向5G微基站的双频双极化电磁偶极子天线设计

文中提出并设计了一款应用于5G微基站的双频双极化电磁偶极子天线,工作带宽完整覆盖了长期演进（long term evolution,LTE）技术的主要频段和5G的全部中频段.该天线首先采用正交放置的渐变式Γ形馈电线对两个交叉放置的电磁偶极子馈电实现双频双极化,随后通过在电偶极子上添加H形缝隙有效扩展了低频段的带宽,最后创新性地引进具有电容性质的圆形寄生贴片将高频频点降低.此外,利用一款添加金属围栏的反射板来改善天线增益和辐射方向图的稳定性.测试结果表明:该天线S_11,22 < -10 dB的阻抗带宽为58.2%（2.11~3.84 GHz）和8.9%（4.72~5.16 GHz）,端口隔离度（|S₁₂|）高于25 dB,双频段内的平均增益分别为8.7 dBi和7.2 dBi;天线E面的半功率波瓣宽度在整个工作频带内的变化为61°±6°,交叉极化比高于20 dB.仿真与测试结果达到了良好的一致性.该天线结构简单、性能优良,可以作为LTE/5G室内基站天线的良好的候选.     

Dual-polarised wideband microstrip antenna

A dual-polarised aperture-coupled microstrip antenna with a wide bandwidth, a high isolation, low cross-polarisation levels and low backward radiation levels is presented. The square patch is fed at two corners via H-shaped apertures. The measured return loss exhibits a bandwidth of over 24.4% and the isolation is better than 30 dB over the bandwidth. The cross-polarisation levels and the front-to-back ratio are better than -23 and 22 dB, respectively     

基于圆形微带贴片谐振器的滤波跨接器设计

提出了一种基于圆形微带贴片谐振器的滤波跨接器,利用圆形微带贴片谐振器中简并模TM11A和TM11B模式的正交性来实现信号的交叉传输.在两个圆形微带贴片谐振器之间引入耦合槽和耦合桥,信号可以从一个圆形微带贴片滤波单元高效传输至另外一个圆形微带贴片滤波单元,亦即将两个圆形微带贴片谐振器级联,从而实现该滤波跨接器的滤波响应....     

A dual polarized aperture coupled circular patch antenna using a C-shaped coupling slot

The design and development of a dual linearly polarized aperture coupled circular microstrip patch antenna at C-band are presented. The antenna uses a novel configuration of symmetric and asymmetric coupling slots. Variations in isolation between orthogonal feedlines and antenna axial ratio with the position of coupling slots are studied and broadband isolation and axial ratio are achieved. The prototype antenna yields 7.6 dBi peak gain, 70/spl deg/ 3-dB beam width, 25 dB cross-polarization levels and an isolation better than 28 dB between the two ports. With an external quadrature hybrid coupler connected to the two orthogonal feedlines, the antenna yields 3-dB axial ratio bandwidth of more than 30% at 5.8 GHz.     

低损耗双模微带贴片带通滤波器研究

首先提出了一种新颖、简单的带有两个切角的双模微带带通滤波器结构。该结构使用单个贴片谐振器并且没有耦合缝隙,通带两端各有一个衰减极点,可以有效减小滤波器的辐射损耗。对该滤波器结构进一步改进,又提出了一种中心频率1.8GHz相互正交槽线的新型双模微带带通滤波器结构。该滤波器在中心频率1.8GHz处,回波损耗达到31.65dB,通带内最小插损为0.01dB,3dB带宽为19.44%。研究结果表明该结构可以进一步减小辐射损耗,并且可以减小滤波器的体积,有利于小型化。     

新型的平面双模椭圆函数带通滤波器

根据传统的方形贴片双模滤波器,提出了一种新颖的带有两个切角的平面双模带通滤波器结构.该结构使用单个贴片谐振器并且没有耦合缝隙,通带两端各有一个衰减极点,有效减小了滤波器的辐射损耗.对该滤波器结构进行改进,又提出了一种带有两个相互正交、长度不等槽线的双模椭圆函数带通滤波器结构.该滤波器在中心频率1.8GHz处,回波损耗达到31.53 dB,通带内最小插损达到0.01 dB,3 dB相对带宽为19.44%.采用Ansotf公司的En-sem ble 8.0仿真软件进行的仿真研究.仿真结果表明该结构可以更加有效地减小辐射损耗,增加带宽,且体积比传统滤波器减小了约40%,有利于小型化.     

Dual-polarized slot-coupled planar antenna with wide bandwidth

A new dual-polarized slot-coupled microstrip patch antenna is presented, which can achieve high-isolation, low cross-polarization levels, a wide bandwidth, and low backward radiation levels. The coupling slot is an H-shaped slot. For wide bandwidth and easy integration with active circuits, it uses slot-coupled stacked microstrip patches. The theoretical analysis is based on the finite-difference time-domain (FDTD) method. First, a parametric study on the input impedance of the antenna with a single input port is presented. Based on the results, a dual-polarized microstrip antenna is designed, fabricated, and then measured. The measured return loss exhibits an impedance bandwidth of over 20.9% and the isolation between two polarization ports is better than 36 dB over the bandwidth. The cross-polarization levels in both E and H planes are better than 22 dB. The front-to-back ratio of the antenna radiation pattern is better than 21 dB. Both theoretical and experimental results of return loss, isolation, and radiation patterns are presented and discussed.     

Wideband dual-polarised microstrip patch antenna

A dual-polarised microstrip antenna capable of achieving a wide bandwidth, a high isolation, low cross-polarisation levels and low backward radiation levels is presented. The H-shaped coupling aperture is used. For wide bandwidth and easy integration with active circuits, it uses the aperture-coupled stacked microstrip square patches. Measured return loss exhibits a bandwidth of over 20.9%, and isolation is better than 36 dB over the bandwidth. Cross-polarisation levels and the front-to-back ratio are better than 22 and 21 dB, respectively     

Broadband dual-polarized patch antennas fed by capacitively coupledfeed and slot-coupled feed

Designs of broadband dual-polarized patch antennas fed by promising feed structures of a capacitively coupled feed and a slot-coupled feed (antenna A), two capacitively coupled feeds of a 180° phase shift and a slot-coupled feed (antenna B), and two capacitively coupled feeds of a 180° phase shift and two slot-coupled feeds (antenna C) are proposed and experimentally studied. The first two feed designs are for the excitation of a single-element broadband patch antenna, while the last design is for a two-element broadband patch antenna. These proposed patch antennas have a thick air substrate, and the 10 dB return-loss impedance bandwidths obtained for the two polarizations are all greater than 13%. High isolation (<-30 dB for antenna A, <-32 dB for antenna B, <-35 dB for antenna C) between the two feeding ports for the entire impedance bandwidth of the proposed antennas can be obtained. Also, improved cross-polarization levels (>20 dB) in both E and H plane patterns for the two polarizations of antennas B and C are achieved     

High mutual coupling reduction between microstrip patch antennas using novel structure

In this paper, a novel parasitic configuration to reduce the mutual coupling between two adjacent microstrip patch antennas is presented. It is shown that mutual coupling between the antenna elements can be reduced significantly by two simple slots structure on the ground plane and several shorted simple conducting strips between patch antennas. The structure has been constructed and tested. Both simulated and measured results are presented. The results are shown that more than 7 dB reduction within operational frequency bandwidth with the maximum 41 dB mutual coupling at center frequency can be achieved. The measurement results prove the high efficiency of this configuration in multi antenna systems.     

小型化缝隙加载圆极化及宽带微带贴片天线设计

提出了一种十字形缝隙加载的小型宽带及圆极化微带贴片天线的设计方法。该天线通过在方形贴片上加载一个大尺寸的十字形缝隙实现天线的尺寸缩减,介质基片采用由FR4和空气层组成的层叠结构,在缝隙中嵌入L型枝节,只需通过调整枝节上同轴线馈电点的位置来获得圆极化或宽带阻抗匹配。ANSYS HFSS仿真分析表明,天线的圆极化带宽（AR≤3 dB）为1.7%,阻抗带宽（VSWR≤2）为5.8%,天线在宽带范围内具有稳定的增益,峰值增益为7.8 dB,同时贴片面积缩减了52.3%。改变馈电点的位置可调节两个谐振频率使天线阻抗带宽达到9.4%,比传统的微带贴片天线阻抗带宽提高了114%。     

基于H形缝隙耦合的宽带圆极化微带天线

制作并测量了一种基于H形缝隙耦合的宽带圆极化微带天线,并讨论了天线的各结构参数对天线性能的影响。测量结果表明：通过Wilkinson功分器馈电,可使天线驻波带宽达47.5％,轴比带宽达50％,方向图前后比达－21dB,实现了低后瓣宽带圆极化微带天线的设计。     

微带线馈电的宽带单层贴片天线

微带贴片天线已广泛应用于雷达系统,文中介绍了一种新型背腔式单层微带贴片天线,辐射贴片采用微带线馈电,为增加工作带宽,提供了两种不同的贴片形状,第一种是E形贴片,仿真及测试结果表明,此种单元在驻波比优于2的条件下可实现45%的阻抗带宽,但该单元的波瓣带宽较窄。为抑制交叉极化,通过在E形贴片上开四个槽,得到了第二种改进的E形贴片。该单元可实现14%的频带内驻波比优于1.5,同时交叉极化优于-15dB。对C波段8×16单元实验小阵的测试结果表明,该天线在17.9%的频段内具有良好的交叉极化性能及较高的工作效率。     

一种倾斜波束双极化天线

提出了一种具有倾斜波束辐射特性的新型双极化天线。该双极化天线由两个正交的纺锤形偶极子 组成,根据准八木天线原理,在偶极子两侧加载寄生振子作为反射器和引向器,用以实现倾斜波束辐射。这种纺锤 形偶极子可以增加电流长度从而减小天线的整体尺寸。同时在每个偶极子贴片上蚀刻两个梯形槽,以实现良好的 阻抗匹配。另外,通过连接到同轴线的金属短截线对纺锤形偶极子进行激励,简化了天线馈电结构。测试结果表 明,天线的阻抗带宽为3. 36~3. 69 GHz(S11 <-10 dB),两个极化端口之间的隔离度大于16 dB,波束倾斜度为30°,波 瓣宽度约为85°,可适用于单侧大角度扫描阵列。     

Analysis of a dual circularly polarized microstrip antenna fed bycrossed slots

A dual circularly polarized, wideband microstrip antenna fed by two perpendicular crossed slots is analyzed in this work. The cross shaped aperture in the ground plane provides coupling between the microstrip patch and a single microstrip line underneath the ground plane, traversing the four arms of the cross in a serial manner, thereby generating four coupling points in phase quadratures for both senses of circular polarization. The analysis of this antenna incorporates two stages: In the first one, the individual load impedances are computed via an integral equation based on reciprocity, assuming no interactions between the ports. The second stage employs a transmission line model where the four coupling points are considered as lumped loads along the feed line. An iterative scheme employs the transmission line model for the determination of the actual impedances of each coupling point, including the mutual interactions with the other coupling points. This procedure provides control over the overall level of radiated energy; hence it can be used in the design procedure of this antenna as a serial or parallel fed array element. The computed results agree very well with measurements. The antenna attains a -3 dB gain bandwidth of 13% to 15%, a 3-dB axial ratio bandwidth of 48%, and -15 dB return loss bandwidth of 60%     

一种H型缝隙和L型探针耦合双极化微带天线的设计

设计了一种宽带、低交叉极化、高隔离度的双极化微带天线结构,采用L型探针耦合和H型缝隙耦合两种方式相结合,结构简单.天线设计频率为2.4 GHz,两端口-10 dB阻抗带宽达到26.7%和30%,隔离度在整个带宽内低于-32 dB、交叉极化电平在60°方位角内低于-24 dB、在主瓣内低于-32 dB,理论仿真和实验测试结果吻合较好.     

Reduced size, dual-polarized microstrip patch antenna for wireless communications

A novel, compact, probe-fed microstrip patch antenna for operation in dual-polarization mode is proposed. The novel design is achieved by etching out a symmetric pattern of crossed slots from the surface of a square probe-fed patch. Reduction in patch size of up to 51% with respect to a traditional dual-polarized square patch operating at the same frequency is obtained. Results show linear polarizations in the +45 and -45/spl deg/ with a high isolation of 38 dB between the two ports. Moreover, the 50-/spl Omega/ feed position can be achieved by moving the feed point along the diagonal of the square patch, leading to ease in fabrication.     

Isolation enhancement for dual‐band MIMO antenna system using multiple slots loading technique

In this paper, a novel multiple slot loading technique is studied in detail for the isolation enhancement of the dual‐band MIMO antenna system. The proposed MIMO antenna design consists of the microstrip patch loaded with T‐shaped slots parallel to the non‐radiating edge of the patch. The frequency tuning could be achieved by varying the length of the T‐shape slot arm. The proposed MIMO antenna system is optimised for operation in WLAN and WiMAX applications. The isolation enhancement is achieved by providing simple multiple slots loaded in the ground plane between radiating elements. The length of the slots is λ/4 . The system is fabricated and tested using a vector network analyser and anechoic chamber. The reduction in mutual coupling up to ?29.16 dB and ?24.09 dB for the 2.4 GHz and 3.4 GHz, respectively, is achieved. The bandwidths are 62.3 MHz (3.33–3.39 GHz) and 55.5 MHz (2.37–2.42 GHz), respectively. The total gain obtained in this case is 1.8 dBi at 2.4 GHz and 1.2 dBi at 3.4 GHz, respectively. The dimensions of the proposed designed antenna are 70 mm × 60 mm × 1.6 mm. The results were also verified through mutual coupling parameters like envelope correlation coefficient (ECC) and channel capacity loss (CCL) at the desired frequencies.     

Improved feed-system for a printed antenna composed of strip dipoles and slots

A new H-shaped feed-network for CP-PASS (circularly polarised printed array composed of strip dipoles and slots) is presented which allows a wider axial-ratio bandwidth to be realised at 12 GHz band. By using the H-shaped feed-network, a 12*2 element-set CP-PASS gives a 3 dB axial-ratio bandwidth of 6%.<>     

Compact ultra-wideband antenna with tri-band notched characteristic

A compact ultra-wideband printed planar antenna with tri-band notched characteristic is presented. Two different types of slots are used to obtain tri-band notched characteristic. By using a U-slot defected ground structure, a notched band, 5?6 GHz for WLAN, is achieved. An H-shaped slot is etched on the radiating patch to obtain another two notched bands at 3.3?3.7 GHz for WiMAX and 7.2 GHz for some C-band satellite communication systems. The proposed antenna yields an impedance bandwidth of 3.1?10.6 GHz with VSWR , 2, except the notched bands. The antenna is successfully simulated and measured, showing tri-band notched characteristic can be obtained by using two different slots.