Active Integrated Antenna Design Using a Contact-Less, Proximity Coupled, Differentially Fed Technique

A novel contact-less, differential feeding technique suitable for integrated active antenna design is demonstrated. This technique utilizes an odd mode signal to generate fringing fields on either side of a microstrip gap under the antenna. This allows electromagnetic energy to be efficiently coupled from the transmission lines to the radiating antenna. In a balanced integrated antenna amplifier configuration, the proposed non-contact feeding method removes the need for any balun or power combining network. Hence in theory, a compact RF front-end design with lower losses can be realized. This feeding method has been successfully applied to the design of simple passive microstrip patch antennas and active integrated antennas (AIA). Simulated and measured results are also included to validate the proposed feeding concept and antenna designs. The performance of the proposed differential feeding technique on a simple microstrip patch antenna has been systematically studied. The study suggests that the proposed proximity method is broadband in nature, allowing antennas operating at different resonant frequencies to be swapped without the need to change the feed dimensions and without degrading the matching performance     

Novel compact circularly polarized square microstrip antenna

A novel compact circular-polarization (CP) operation of the square microstrip antenna with four slits and a pair of truncated corners is proposed and investigated. Experimental results show that the proposed compact CP design can have an antenna-size reduction of about 36% as compared to the conventional corner-truncated square microstrip antenna at a given operating frequency. Also, the required size of the truncated corners for CP operation is much greater than that for the conventional CP design using a simple square microstrip patch, providing a relaxed manufacturing tolerance for the proposed compact CP design. Details of the experimental results are presented and discussed     

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     

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     

折叠短路式小型化双层微带天线

微带天线在各种内置天线通讯系统中有非常重要的应用.为满足便携式设备小型化的需要,该文介绍一种折叠式双层正方形微带贴片天线.此天线根据曲流原理,把常规的微带天线进行折叠.与常规微带天线相比,折叠式微带天线的尺寸减小了60%以上.折叠天线结构紧凑,便于加工制作.文中给出了天线的详细设计方案以及仿真结果.仿真结果证明该设计完全可以满足工程要求.     

Compact circularly polarised microstrip antenna with bent slots

By embedding a group of four bent slots in a corner-truncated square microstrip patch, a single-feed compact circularly polarised microstrip antenna can easily be obtained. Results show that for a given circular polarisation (CP) operation, the proposed antenna can have an antenna size reduction of more than 50% as compared to the conventional CP design using a corner-truncated square patch without the slots. Moreover, the 50Ω feed position and truncated-corner size for achieving CP operation are found to be nearly independent of the bent slots introduced in the patch, which makes the proposed antenna easy to implement     

MAMA: a new methodically designed broadband microstrip antenna using off-the-shelf components

The current paper proposes a new, simple, methodical approach to broadband microstrip antenna design. The approach relies on a reformulation of the antenna-design problem as an impedance-matching problem, in which the antenna is considered to be the matching device required to match the feed line to air. Thus, impedance-matching techniques, such as Chebyshev transformers and a Klopfenstein taper, are employed to determine the antenna parameters necessary to satisfy a set of specifications. Simulation results as well as measured results show that the proposed matched-to-air microstrip antennas (MAMAs) qualify as a new class of broadband microstrip antennas, which have the advantages of relying on a systematic approach (as opposed to the usual trial-and-error procedures that are now prevalent), as well as being very easy to fabricate, using inexpensive off-shelf components.     

Analysis and design of broad-band single-layer rectangular U-slot microstrip patch antennas

A wide operating bandwidth for a single-layer coaxially fed rectangular microstrip patch antenna can be obtained by cutting a U-shaped slot on the patch. This antenna structure has recently been found experimentally to provide impedance bandwidths of 10%-40%, even with nonair substrates. However, design rules for this antenna have not yet been presented. This paper develops principle design procedures through examination of the structure's multiple resonant frequencies as well as the radiation and impedance properties of different antenna geometries. The approximate design rules are derived by analysis of former experiments, method of moments (MoM) simulations, and measurement results. Simulations and measurements of several antennas designed using these new rules are presented and directions for further study are discussed.     

Small slot-coupled circularly-polarised microstrip antenna withmodified cross-slot and bent tuning-stub

A novel design of small slot-coupled circularly-polarised circular microstrip antenna with a modified cross-slot cut in the patch and a bent tuning-stub aligned along the patch boundary is proposed and experimentally studied. Results show that, for fixed circular polarisation (CP) operation, the antenna proposed can have an antenna size reduction of ~80%, as compared to a regular-size CP design. The significant size reduction of the proposed antenna is due to the novel modified cross-slot cut in the patch, and CP operation is obtained using a bent tuning-stub incorporating a properly oriented coupling-slot in the ground plane of the microstrip feed line     

Compact design of single-feed circularly polarised microstrip antenna

A compact design of a single-feed circularly polarised (CP) microstrip antenna with relaxed manufacturing tolerances is presented. The CP operation of the microstrip antenna is achieved using a cross slot embedded on the radiating patch. By cutting an additional cross slot on the ground plane, not only the CP operating frequency can be decreased but also the slot-length ratio of the cross slot on the radiating patch can be considerably increased. In addition, the performance of the proposed design, such as CP bandwidth and peak gain, have no significant reduction.     

Single-feed slotted equilateral-triangular microstrip antenna forcircular polarization

Novel designs of single-feed equilateral-triangular microstrip antennas for circular polarization (CP) are proposed and studied experimentally. It is demonstrated that by embedding a narrow slot or a cross slot of unequal slot lengths in the triangular patch, circularly polarized radiation of microstrip antennas can easily be achieved using a single probe feed. Furthermore, results show that for the design with a cross slot, the proposed antenna can perform CP radiation with a reduced antenna size at a given frequency (denoted as compact CP operation here); that is, the required antenna size is smaller for the proposed antenna for performing CP radiation as compared to a conventional circularly polarized triangular microstrip antenna at a fixed operating frequency. Details of the proposed CP designs are described, and typical experimental results are presented and discussed     

Single-feed circularly polarized equilateral-triangular microstripantenna with a tuning stub

Novel circular polarization (CP) designs of single-feed equilateral-triangular microstrip antennas are proposed and experimentally studied. The proposed CP designs can easily be achieved by loading a narrow tuning stub at the triangle tip or at the center of the bottom edge of the triangular patch. Moreover, by embedding a cross-slot of equal slot lengths in the triangular patch, a compact CP operation can easily be obtained, with an antenna size reduction up to about 22%, as compared to the CP design of a regular triangular microstrip antenna without cross-slot at a fixed frequency     

一种新型双极化口径耦合微带天线单元的研究

本文在比较了一些微带天线实现双极化思路后,提出了一种新型高极化隔离度和低后向辐射的双极化微带贴片结构:即在口径耦合单元的馈线上增加一对对称寄生微带线调节枝节,进行匹配阻抗和实现高极化隔离度,并利用H形口径耦合,减小贴片单元的后向辐射,提高天线的辐射效率。该结构简单,调节简便,馈线网络占有面积较小,且易做成更大规模的双极化天线阵,非常适合现在高分辨率双极化合成孔径雷达和抗多径干扰高的移动通讯系统的需要。文中给出了仿真和实测结果,吻合较好,从而证明了设计的有效性。     

Design of aperture-coupled annular-ring microstrip antennas for circular polarization

The design of an aperture-coupled annular-ring microstrip antenna for circular polarization (CP) is presented. The CP radiation of the annular-ring microstrip antenna is achieved by a series microstrip-line-feed configuration through the coupling of a ring slot in the ground plane. The key parameters of the proposed design are investigated using a commercial simulation software based on the Method of Moments to show how to obtain the 50 /spl Omega/ input impedance and optimum axial ratio. The proposed design can be applied to the annular-ring microstrip antennas with different inner radii and substrate thickness, and several antenna prototypes are constructed and measured. Details of the experimental results of the CP performance are presented and discussed.     

Novel dual-frequency and broad-band designs of slot-loadedequilateral triangular microstrip antennas

By loading properly arranged slots in an equilateral-triangular microstrip patch, novel dual-frequency and broad-band operations of a single-feed triangular microstrip antenna are presented. For dual-frequency operation, the proposed design is achieved by loading two pairs of narrow slots in the triangular patch, one embedded close to the side edges of the patch and the other inserted at the bottom edge of the patch. The obtained two operating frequencies are of same polarization planes and by varying the positions and lengths of the inserted slots at the bottom edge of the patch, a tunable frequency ratio of the two frequencies ranging from about 1.16 to 2.06 is obtained. Furthermore, it is found that by protruding a narrow slot out of the embedded slots close to the side edges, broad-band operation of the triangular microstrip antenna near its fundamental resonant mode can be achieved. Results show that the antenna bandwidth of the proposed broad-band design can be greater than 2.6 times that of a conventional triangular microstrip antenna. Details of the proposed dual-frequency and broad-band designs are described and typical experimental results are presented and discussed     

一种新型宽波束圆极化微带天线的设计

设计了一种新型宽波束圆极化微带天线,该天线采用四探针馈电,馈电网络由威尔金森功分器和传输线移相器组成,使四个馈电探针的相位依次相差π/2,实现了右旋圆极化辐射。通过Ansoft HFSS仿真结果表明：该微带天线结构简单、极化纯度高、全向性能好、轴比小于3dB的圆极化带宽达到27.7%,高于一般的微带圆极化天线（轴比小于3dB带宽约为15%）。天线可以很好地满足GPS通信的技术要求,也可用于无线局域网。     

Square-ring microstrip antenna with a cross strip for compactcircular polarization operation

A novel design of square-ring microstrip antenna with a cross strip for achieving compact circular polarization (CP) operation is proposed and experimentally studied. The cross strip can be placed in the centerlines or diagonals of the square-ring patch. Either design can make its excited fundamental mode patch surface current path much longer than that in a conventional square microstrip antenna with same antenna size. By incorporating a small tuning stub for splitting the fundamental mode into two near-degenerate resonant modes with equal amplitudes and 90° phase-difference compact CP operation for the proposed design can he obtained     

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 dual-frequency rectangular microstrip antenna withsquare slot

By cutting a square slot at the centre of a rectangular microstrip patch, both compactness and dual-frequency operation can be achieved. Several designs have been implemented. From the experimental results obtained, the required antenna size using the proposed design method can be reduced by ~17% compared to that of the conventional design method using a simple patch without the slot. Typical experimental results are presented and discussed     

矩形微带天线的一种快速优化设计方法研究

针对矩形微带天线优化设计主要依赖经验和反复试验的现状,研究提出了一种矩形微带天线的快速优化设计方法。分析了传输线理论对矩形微带天线分析时的准确性,并将传输线理论成功地与改进的量子遗传算法(IQGA)相结合,应用于矩形微带天线的优化设计之中。利用该方法优化设计了一款矩形微带天线,通过将设计分析的结果与有限元软件HFSS计算结果比较,说明该算法的高效性及准确性。为方便该方法的应用,开发了一款矩形微带天线的快速优化设计软件包。