Broadband triangular microstrip antenna with U-shaped slot

The broadband design of a triangular microstrip antenna with a U-shaped slot is demonstrated. With a foam substrate of thickness ~0.08 λ₀, a slotted triangular microstrip antenna with an operating bandwidth of ~18% is obtained, which is ~1.8 times that of a corresponding simple triangular patch antenna. Details of the antenna design and experimental results are presented     

Single-feed circularly polarized microstrip ring antenna and arrays

An analysis is presented for a microstrip-feed proximity-coupled ring antenna and a four-element array. Interactions between the embedded microstrip feed and the radiating element(s) are rigorously included. Results demonstrate that circular polarization of both senses can be achieved with a ring antenna with proper design of two inner stubs located at angles of ±45° with respect to the feedline. Theory and experiment demonstrate an axial ratio 3-dB bandwidth of 1% and the voltage standing wave ratio (VSWR) <2 bandwidth of 6.1%. The axial ratio bandwidth is typical for a microstrip antenna with perturbations, while the VSWR bandwidth is larger than for the circular or rectangular patch with perturbations. A mutual coupling study between two elements shows that the axial ratio is less than 2 dB for interelement spacing greater than 0.55λ_eff, while the VSWR <2 for all spacings considered. A comparison between theory and experiment is provided for a 2×2 element array. The benefits of sequentially rotating the antenna elements in an array environment are presented. The axial ratio and VSWR bandwidths are both increased to 6.1% and 18% for a four-element array. A single-element antenna with two orthogonal feeds to provide both senses of polarization is demonstrated. The ring antenna is small (D/λ₀=0.325), the substrate thickness is thin (H/λ₀~0.035), and the microstrip feed produces a completely planar antenna system, which is compatible with microwave and millimeter integrated circuits (MICs), and monolithic microwave integrated circuits (MMICs)     

层状磁电复合基板微带天线设计及应用

 本文提出一种新的小型化、宽频带微带天线.采用以层状磁电复合材料为基板的微带天线形式,推导了设计公式并给出计算结果.与介质基板矩形微带天线相比,该磁电复合基板天线的尺寸缩小了40%多,而带宽约为6%,是介质基板天线4倍.     

A Single-Layer Ultrawideband Microstrip Antenna

A single-layer microstrip antenna for ultrawideband (UWB) applications, in which an array of rectangular microstrip patches was arranged in the log-periodic way and proximity-coupled to the microstrip feeding line, is presented. In order to reduce the number of microstrip patches in the UWB log-periodic arrays, a large scale factor ${rm k}=1.1$ was firstly reported and proved to be highly effective. Furthermore, instead of using an absorbing terminal loading, a novel loss-free compensating stub was proposed. Detailed parameters study was also presented for better understanding of the proposed antennas. The impedance bandwidth (measured ${rm VSWR}≪2.5$ ) of an example antenna with only 11 elements is from 2.26–6.85 GHz with a ratio of about 3.03:1. Both numerical and experimental results show that the proposed antenna has stable directional radiation patterns, very low-profile and low fabrication cost, which are suitable for various broadband applications.      

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     

Compact broadband E-shaped microstrip antennas

A broadband E-shaped microstrip antenna is discussed. Its bandwidth is further increased by cutting a pair of tapered slots. Using the even-mode symmetry of an E-shaped microstrip antenna, a compact single slot loaded rectangular microstrip antenna is proposed, which reduces the antenna size by half.     

宽带毫米波微带天线的设计与分析

根据微带天线的设计技术要求,介绍了微带天线带宽的影响因素。在矩形毫米波微带天线设计与分析的基础上,分别设计出 C 型和 W 型两种宽带毫米波开槽微带天线。利用仿真软件对3 种天线的输入回波损耗、驻波系数、相对带宽和方向性等技术参数进行仿真优化和比较分析。仿真与实验结果表明,3 种天线的设计均满足技术要求,C 型和 W 型开槽微带天线较矩形微带天线的相对带宽大幅提高,且具备良好的定向辐射特性。     

Broadband circular microstrip antenna with embedded reactiveloading

A novel broadband design for a circular microstrip antenna with reactive loading integrated within the circular patch is proposed and studied. The reactive loading is provided by a microstrip structure of cascaded microstrip-line sections embedded inside a slot cut in the circular patch. The proposed broadband design has been implemented, and the experimental study shows that an antenna bandwidth ~3.2 times that of a conventional circular microstrip antenna can be obtained. Details of the proposed design are described, and experimental results of the antenna performance are presented and discussed     

Novel Broadband Circularly Polarized Cavity-Backed Aperture Antenna With Traveling Wave Excitation

A novel broadband circularly polarized aperture antenna is presented that uses traveling-wave excitation as the design concept. The antenna configuration consists of a circular radiating aperture, a backed cavity, and an equiangular tapered strip outer-fed by a microstrip transmission line. Operating with a traveling wave excitation, the proposed antenna contains inherent broadband characteristics in terms of the impedance, axial ratio, and gain performances. The presented antenna is comprehensively investigated, including the working principles, design consideration, and parametric studies. In addition, the research interests are extended to a 2$,times,$ 2 antenna array. Promising results from the experimental 2$,times,$2 array are achieved, including the 10-dB return loss bandwidth of 70%, the 3-dB axial ratio bandwidth of 50%, and the half-power (3-dB) gain bandwidth of 40% with a maximum gain about 11 dBi. The measured and simulated results are well complied with each other.      

On a Broadband Elevated Suspended-Plate Antenna with Consistent Gain

A design concept for elevating suspended-plate radiators is presented in this paper. The proposed antenna comprises two radiators connected by a folded feeding structure. The folded structure suppresses the occurrence of higher-order modes when the height of the antenna is elevated beyond 10% of the free-space wavelength, lambda₀ . The broadband radiating mechanism is explained. Both the simulation and measurement results show that a consistent gain of 7.2 dBi to 8.5 dBi is achieved over a frequency range of 2.3 GHz to 3.6 GHz, namely within a 44% impedance bandwidth for |S₁₁|< -10 dB. The concept is used to design two cost-effective broadband antennas covering both WLAN and WiMAX operations.     

Bandwidth enhancement of inset-microstrip-line-fedequilateral-triangular microstrip antenna

By embedding a pair of properly-bent narrow slots in an equilateral-triangular microstrip patch, broadband operation of microstrip antennas with an inset microstrip-line feed can be achieved. With the proposed antenna design, the impedance bandwidth can be as large as ~3.0 times that of a corresponding simple triangular microstrip antenna. Some simple design rules for the proposed antenna have also been determined experimentally. The design rules and experimental results are presented and discussed     

Broadband circularly-polarised Spidron fractal slot antenna

A broadband circularly-polarised fractal antenna is proposed, designed, and tested. The concept of a novel Spidron fractal system is employed to achieve both broadband and circular-polarisation characteristics. Presented is the first known application of a Spidron fractal to antenna design. A simple 50 ω microstrip line is used to excite the Spidron-shaped slot. The total dimensions of the fabricated antenna are 40 X 40 X 1.52 mm³. The measured -10 dB return loss bandwidth and the 3 dB axial ratio bandwidth are 78.3 and 15.2%, respectively. The peak gain of the antenna is 4.3 dBi.     

Metamaterial-based compact zeroth-order resonant antenna

A metamaterial-based compact one-unit-cell antenna realised on a microstrip line is presented. The size of the proposed antenna is only 6 X 13.5 mm (or 0.05 X 0.13 λ₀) at 2.7 GHz owing to zeroth-order resonance. The design procedures with closed-form solutions are provided using transmission line theory considering radiation loss. The measured antenna bandwidth is 15 MHz and total gain is 1.22 dBi.     

Slotted rectangular microstrip antenna for bandwidth enhancement

With the loading of a pair of right-angle slots and a modified U-shaped slot in a rectangular microstrip patch, novel bandwidth enhancement of microstrip antennas is demonstrated. The required dimensions of the right-angle slots and modified U-shaped slot for bandwidth enhancement with good radiating characteristics have been determined experimentally in this study and the obtained antenna bandwidth can be as large as about 2.4 times that of a corresponding unslotted rectangular microstrip antenna. Details of the antenna design and experimental results are presented and discussed.     

一种新型布局的圆极化微带天线阵优化设计

提出了一款高增益低副瓣新型圆极化微带天线阵。单元天线采用叠层切角圆极化微带结构,通过八边形边界布局和顺序旋转交叠组阵技术,实现了天线阵方向性图的对称性和圆极化辐射性能的最优化;馈电网络采用威尔金森功分器和最大平坦式阻抗变换器实现不等功分宽带阻抗匹配,通过改进馈电方向寻求对称结构,简化了馈电网络的设计。制作了天线阵实物并进行了测量。测试结果表明:天线在3.2~4.6 GHz频段内S₁₁<-10 dB,阻抗相对带宽36%;在3.8~4.5 GHz频段内顶点轴比小于3 dB,圆极化相对带宽17%;在4~4.4 GHz频段内天线增益均在15 dB以上,最高增益达17 dB。     

A Novel Compact Printed Antenna Used in TPMS or Other Complex and Variable Environments

A novel compact printed antenna used in tire pressure monitoring system (TPMS) is proposed and analyzed in this paper. The proposed antenna is printed on both sides of the dielectric substrate and the upper side consists of four parts: (1) the meandered radiating sections; (2) the additional strip line, which is used as a shorting connector and an additional radiating portion; (3) the feed microstrip line; and (4) the loading meandered sections, which are mainly used to improve the impedance bandwidth. The lower side consists of a meandered ground plane, which can also act as a balun choke and the extended parallel strap, which acts not only as a shorting connector but also as an impedance-tuning strap. A prototype of the proposed antenna with 0.17 lambda₀ in length, 0.017 lambda₀ in width and 0.0021 lambda₀ in height has been fabricated and tested. The relative impedance bandwidth of the proposed antenna reaches 22% (VSWR < 3.0) and 12% (VSWR < 2.0), and the antenna has an acceptable relative gain and its performance is relatively stable. Therefore, it also can be used in other complex and variable environments besides TPMS. When the length of the antenna is reduced to 0.098 lambda₀, the relative impedance bandwidth exceeds 28% (VSWR < 2.0). But the antenna's performance will become less stable, which may be the same as that of the conventional compact monopole antenna. Design details of the proposed antenna and the results of both simulations and experiments are presented and discussed.     

基于HFSS的无线传感器网络节点微带天线设计与仿真

根据微带天线的辐射原理,设计一种谐振频率为2.47 GHz的矩形微带天线,并对微带天线频带的展宽方法进行了研究。通过附加贴片来修改等效谐振电路,使其具有多个谐振点,从而扩展阻抗带宽,仿真结果表明该天线的阻抗带宽达到了12%(300 MHz)。该天线具有体积小、宽频带和低抛面等特点,可作为无线传感网络节点的终端天线,具有一定的工程应用价值。     

L-probe proximity-fed annular ring microstrip antennas

A broadband single-layer annular ring microstrip antenna fed by an L-shaped probe is studied. It achieves, for the TM₁₁ mode, an impedance bandwidth of about 24% [standing wave ratio (SWR) ⩽2], a 3-dB gain bandwidth of 33%, and a maximum gain of 7.5 dBi. For the TM ₁₂ mode, an impedance bandwidth of about 27% (SWR ⩽2), a 3-dB gain bandwidth of 15.5% and a peak gain of 10.3 dBi are obtained. A foam substrate of thickness around 10% of the operating wavelength in free-space is used as the supporting substrate. The far-field radiation patterns are stable across the passband     

Broadband semicircle-fed flower-shaped microstrip patch antenna

A new wideband flower-shaped microstrip antenna patch, semicircle-fed, is investigated. The broadband characteristic is achieved by introducing flower petals at the four sides of a rectangular patch. The proposed antenna is able to achieve an impedance bandwidth of 63% for VSWR less than 2. Using the same excitation mechanism, a comparison between the proposed antenna, a similar-size rectangular-shaped patch antenna and a diamond-shaped patch antenna is given.     

Small broadband disc-loaded monopole antenna with probe feed and folded stripline

A small broadband disc-loaded monopole antenna with a probe feed and folded stripline is presented. The antenna is composed of a rectangular disc with multiple shorting pins and a probe feed with a folded stripline that are coupled electromagnetically. The dimensions of the proposed antenna are 12/spl times/12/spl times/10 mm, and it has a measured impedance bandwidth of 700 MHz for VSWR <2 with a centre frequency at 2.54 GHz, which is approximately 27.5% of a fractional bandwidth.