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     

The Application of Lumped Element Equivalent Circuits Approach to the Design of Single-Port Microstrip Antennas

A simple method for inverting negative resistances of nonphysical circuits generated from approximating rational functions through vector fitting is proposed. This technique is applied to three resonant antenna structures. The challenge of applying this method to these structures lies in the accurate modeling of the ways in which the different resonant modes are excited, some via coaxially feeding a rectangular patch along the diagonal, while others via capacitively coupling energy from the driven patch to a parasitic patch. The equivalent circuits of these designs produce scattering parameter results that are consistent with the fitted functions. This methodology of resistance invertibility is a great tool that can be used to model antenna designs with low order equivalent circuits, drastically reducing the design time. In addition, valuable information that could aid in the optimization of microstrip antennas can be quickly ascertained through these techniques.     

An aperture coupled microstrip antenna with a proximity feed on a perpendicular substrate

A new feeding configuration for microstrip antennas is described, where separate substrates are used for the radiating patch element and the microstrip feedline. The substrates are joined perpendicular to each other, and the patch is excited through an aperture in the antenna substrate ground plane by proximity coupling to the microstrip feedline, This design thus has a number of advantages over other feeding configurations, particularly when used in an integrated phased array application. These features, as well as the measured results from two experimental models, are described.     

A method for designing broad-band microstrip antennas inmultilayered planar structures

The narrow bandwidth of a microstrip antenna is one of the important features that restrict its wide usage. A simple and practical method for the design of broad-band microstrip antennas is presented in this paper. Utilizing this design technique, several two-layer microstrip antennas have been proposed. To confirm the applicability of the method for the designs of antennas at L-band, experiments have been carried out. The measured results show that the proposed antennas have a bandwidth of up to 25.7%. Also, the method proposed in this paper is applicable to the design of other types of multilayered planar antennas     

An asymmetric feeding X-band active frequency-scanning leaky-wave antenna

An asymmetric feeding X-band active leaky-wave antennas is developed, to excite the first high order mode of the microstrip leaky wave antenna. One is the asymmetric feeding leaky-wave antenna which integrated with a HEMT oscillator, and the other is the frequency-tuned leaky-wave antenna which integrated with a varactortuned HEMT VCO. The microstrip leaky-wave antenna is operated in the first higher mode. To excite the first higher mode, the microstrip leaky-wave antenna is fed asymmetrically. The dominant mode excitation has been successfully suppressed by adding a sequence of covered wire in the center of the microstrip leaky wave antenna. The design of these active leaky-wave antennas is discussed and the beam scanning phenomena of the antenna is presented. The HEMT oscillator frequency is controlled by tuning the varactor DC bias and the beam scanning is demonstrated. The measured scanning angle agree with prediction, it is close to 30° as the VCO frequency tuned from 8.06 GHz to 9GHz.     

有源集成天线的谐波平衡法分析

本文首先利用矩量法计算平面馈电型微带贴片天线的输入阻抗,并对其进行实验测量;其次,使用谐波平衡法分析了以Ｃｕｎｎ管为振荡源的有源微带天线电路。在求解谐波平衡方程时采用Ｐｏｗｅｌｌ优化法,得出整体电路的振荡频率和振荡电压;再次,仍使用谐波平衡法对肖特基二极管与微带贴片天线集成的接收型有源天线进行大信号的小信号分析,同样经过优化,得出其在本振电压作用下,非线性部分的谐波电压以及在小信号电压作用下的变频     

Compact microstrip-T coupled patch antenna for dual polarisation and active antenna applications

A novel way of feeding single-layer microstrip patch antennas using electromagnetically coupled microstrip-T junctions is proposed. The measured isolation and 10 dB bandwidth of an X-band dual polarised antenna are /spl sim/32 dB and 2.1%, respectively, on an /spl epsiv//sub r/ 3.0 substrate. Since both ports of the antenna are electromagnetically coupled, the proposed antenna eliminates the need for capacitors in the RF path for active antenna applications.     

Design and Experiment on Differentially-Driven Microstrip Antennas

Design and experiment is given of differentially-driven microstrip antennas. First, the design formulas to determine the patch dimensions and the location of the feed point for single-ended microstrip antennas are examined to design differentially-driven microstrip antennas. It is found that the patch length can still be designed using the formulas for the required resonant frequency but the patch width calculated by the formula usually needs to be widen to ensure the excitation of the fundamental mode using the probe feeds. The condition that links the patch width, the locations of the probe feeds, and the excitation of the fundamental mode is given. Second, the wideband techniques for single-ended microstrip antennas are evaluated for differentially-driven microstrip antennas. A novel H-slot is proposed for differentially-driven microstrip antennas to improve impedance bandwidth. Third, the effects of imperfect differential signal conditions on the performance of differentially-driven microstrip antennas are investigated for the first time. It is found that they only degrade the polarization purity in the -plane with an increased radiation of cross-polarization. Finally, both differentially-driven and single-ended microstrip antennas were fabricated and measured. It is shown that the simulated and measured results are in acceptable agreement. More importantly, it is also shown that the differentially-driven microstrip antenna has wider impedance bandwidth of measured 4.1% and simulated 3.9% and higher gain of measured 4.2 dBi and simulated 3.7 dBi as compared with those of measured 1.9% and simulated 1.3% and gain of measured 1.2 dBi and simulated 1.2 dBi of the single-ended microstrip antenna.     

应用于MIMO系统终端的腰带式可穿戴天线

提出一种应用于MIMO无线通信系统移动终端的腰带式可穿戴外置多天线.这一MIMO多天线系统利用合理的布局,可获取各种分集增益.天线单元采用开槽的电磁耦合微带贴片天线,减小了天线尺寸,也降低了人体吸收率.通过MIMO系统试验平台的外场测试,得到了多天线系统的相关性系数矩阵以及误码率等重要的实验数据.测试结果表明:在保持总发射功率不变的情况下,相较于传统的单发单收天线,这一多天线系统可显著降低传输误码率,进而有效提高通信系统容量与质量.     

Aperture-coupled microstrip antenna with a perpendicular feed

A new technique is described for feeding printed antennas. A microstrip antenna on one substrate is coupled through an electrically small aperture to a microstrip feed line on a perpendicularly oriented substrate. No direct connection is made to the patch. Such a geometry allows two separate substrates to be used for the antenna and feed functions. Measurements of a prototype design are presented.     

Circularly polarised microstrip antenna with a tuning stub

A simple circular polarisation (CP) design of microstrip antennas using a tuning stub is proposed and studied. It is also demonstrated that, by applying this CP design method to a circular microstrip patch with a cross slot having equal slot lengths, a compact circularly-polarised microstrip antenna can easily be implemented, with much more relaxed manufacturing tolerances as compared to the case of using a cross slot of unequal slot lengths. Details of the antenna designs are described, and experimental results are presented and discussed     

Center-fed microstrip patch antenna

A novel feeding scheme for microstrip patch antennas is presented, which consists of a coaxial probe and shorting pin separated by a narrow slot centrally cut at the radiating patch. The impedance and radiation characteristics of a conventional probe-fed microstrip patch antenna and the proposed microstrip patch antenna are experimentally examined and compared. The effects of the slot length on the antenna operation are also discussed.     

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     

一种微带开槽小型化飞行器天线设计

本文根据曲流原理,采用微带开槽技术,设计了一种基于传统半波微带贴片天线的小型化飞行器天线。对此 天线进行了天线与天线窗一体化仿真优化。该天线在主要性能指标不变情况下,明显减小了微带贴片尺寸。把这一设 计应用于实际微带天线调试过程中,发现了微带天线开槽调试法,实现了飞行器微带天线的双向调试,提供了一种新 的天线工程化设计思路。为飞行器小型化微带天线设计和调试提供理论参考,具有一定的理论价值和较高工程应用价 值。     

有源微带天线阵列的实验研究

本文提出了一种混和集成型有源阵列天线结构，并对这一结构进行了空间功率合成的实验研究。功率源采用微带型振荡电路；天线采用矩形微带贴片阵列，二者通过背馈相连。贴片天线阵间的互耦使振荡单元间实现注入镇定，各单元的辐射功率在空间实现合成。在Ｘ波段成功地实现了四单元有源阵列的互锁和空间功率合成。本文报导了实验结果并给出了一些有意义的结论     

Dual-band circularly-polarized square microstrip antenna

New designs of obtaining dual-band circular polarization (CP) radiation of a single-feed square microstrip antenna are proposed and experimentally studied. The proposed single-feed dual-band CP designs are achieved by inserting four T-shaped slits at the patch edges or four Y-shaped slits at the patch corners of a square microstrip antenna. From experiments conducted, a patch size reduction as large as 36% for the proposed design, compared to a conventional CP design without the inserted slits, has been obtained. Details of the design considerations of the proposed antennas are described, and experimental results of the obtained dual-band CP performances are presented and discussed     

Theoretical Investigation of the Input Impedance of Gap-Coupled Circular Microstrip Patch Antennas

In this paper, we have explored a simple theoretical input impedance computation technique for the two gap-coupled circular microstrip patch antennas by using circuit theory approach. The frequency characteristics of the input impedance of the two gap-coupled circular microstrip patch antennas with the gap-distance between the feed patch and parasitic patch is analyzed and simulated. The effect of feed location in the feed patch on the input impedance of proposed antenna is also studied. The theoretical results are compared with the simulated results as well as other reported literature. The simulation has been performed by using a method-of-moment based commercially available simulator IE3D.     

Microstrip patch array antenna

A microstrip array with mutual coupled rectangular patch radiators is described. By the avoidance of a corporate feeding network, advantages in the antenna performance and design are realisable. Experimental results are presented for both linearly and circularly polarised antennas which demonstrate the usefulness of this special antenna configuration.     

Circular polarised microstrip patch antennas for broadband and dual-band operation

A novel design of microstrip patch antennas for circular polarisation (CP) is proposed. As an example, two CP patch antennas are investigated: a broadband CP patch antenna and a dual-band CP patch antenna. The proposed structure can be achieved by embedding circular holes in the microstrip circular resonator. By changing the size and position of loaded holes, two orthogonal modes are simultaneously excited with equal amplitude and /spl plusmn/90/spl deg/ out of phase. Without any 90/spl deg/ phase-shifter, the proposed CP patch antennas are excited by single feed.     

Circuit model of microstrip patch antenna on ceramic land grid array package for antenna-chip codesign of highly integrated RF transceivers

This paper presents the circuit model of a microstrip patch antenna on a ceramic land grid array (CLGA) package for the antenna-chip codesign of a highly integrated radio-frequency (RF) transceiver. The microstrip patch antenna is fed by packaging interconnect components such as bond wires, signal traces, and vias in a ground-signal-ground (G-S-G) configuration from the carried chip. The circuit model that consists of RLC lumped elements of both microstrip patch antenna and feeding interconnect components has been developed with an emphasis on verifying existing or deriving analytical formulas. The RLC values of the microstrip patch antenna are calculated with our improvements to existing computer-aided design formulas, while the RLC values of the feeding interconnect components are calculated with more efforts. In particular the C values related to the vias and signal traces require to be calculated numerically and they are calculated here with the method of moments and the conformal mapping method, respectively. The circuit model is validated with numerical simulations (High Frequency Structure Simulator) and network analyzer measurements.