Ultra Wideband Co-planer Microstrip Patch Antenna for Wireless Applications

In this paper, a comparative study of co-planar gap coupled rectangular and elliptical microstrip patch antenna is presented. It is analyzed by using circuit theory concept. The proposed antennas show ultra wideband operations which depend on dimensions of the patches, gap between them as well as air gap thickness. It is observed that the performance of gap coupled elliptical patch antenna is better than that of rectangular patch antenna while the area of rectangular and elliptical patches is same. The bandwidth of proposed rectangular patch antenna is found to be 50.7 % with average gain of 6.5 dBi while for elliptical patch antenna the bandwidth and gain further improves up to 57.6 % and 9.5 dBi respectively. The theoretical results are in good agreement with the simulated results obtained from IE3D simulation software.     

A Compact Rectangular Dual Patch Antenna for Multiple Satellite Communication Applications

At present, with the advances in satellite communication systems and their increasing importance, wideband antennas are in great demand for both military and commercial applications. Most of the communication systems need a wideband antenna that operates on multi-octave frequencies. In patch antenna, diverse techniques played a vital role in enhancing the antenna parameters such as gain or bandwidth. A new design concept of a compact rectangular dual patch antenna has been developed for both high gain and wider bandwidth. In this work, a compact rectangular dual patch antenna is proposed as a wideband antenna for multiple satellite communication applications such as Global Positioning System, Global Navigation Satellite System, Indian Regional Navigation Satellite System, and S-Band Satellite Communication. The designed rectangular dual patch antenna is simulated and fabricated. Based on the performance, the fabricated antenna is compared with the simulated results in terms of VSWR, gain, axial ratio, and 3 dB beam width. Increased gain and wider bandwidth have been achieved with the developed rectangular patches and their energy distributed on the surface of the dual patches simultaneously. Finally, the proposed rectangular dual patch antenna shows improved performance for the multiple satellite communication applications.

     

Measurement and analysis of miniature multilayer patch antenna

Although the microstrip patch antenna has a number of advantages such as low-cost and light weight, its physical size is quite large at low microwave frequencies. The designs of multilayer miniature patch antennas with coaxial feed are presented. The first design is a rectangular two-layer patch antenna. Measured results and the results of a preliminary analysis are presented. The projection area of the two-layer patch antenna is kept the same as the single-layer rectangular patch antenna. The resonant frequency of the two-layer antenna is reduced by 50% and has bandwidth of 5%, which is wider than the single-layer rectangular patch antenna. In the second design, the upper patch is cut into a bow-tie shape. This results in a 60% reduction in resonant frequency and a 12% bandwidth. Both the two-layer rectangular and the two-layer bow-tie antennas have good radiation patterns, with cross-polarization level lower than the copolarization level by more than 20 dB     

A New Method for Measuring Dielectric Constant Using the Resonant Frequency of a Patch Antenna

An analytical expression is given for the resonant frequency of a rectangular patch antenna. It shows explicitly the dependence of the resonant frequency on the characteristic parameters of a patch antenna. Based on this result, a new method is developed for the measurement of the dielectric constant of a thin slab substrate. Basically, the test equipment consists of a rectangular microstrip antenna the patch of which is fed either by a microstrip line or coaxial line. From the measured resonance parameters of the rectangular patch antenna, the dielectric constant can be easily obtained. The measured values of the present method are in agreement with the precision standard cavity resonator method. Accuracy of the dielectric constant so obtained is satisfactory.     

Oscillator noise reduction in cavity-backed active microstrip patchantenna

A rectangular cavity-backed active microstrip patch antenna has been investigated Experimental results show that 25 dB oscillator noise reduction can be achieved for the active patch antenna at a carrier frequency of 4.1 GHz and an offset frequency of 8 kHz by using a rectangular cavity     

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.     

用于WLAN/WiMAX的双频紧凑型天线

提出了一种新型共面波导馈电的小型双频宽频带天线。天线由一环形单极子和一矩形贴片组合而成,矩形贴片嵌在环形单极子内部,使得天线结构紧凑。天线分别由矩形贴片和环形单极子辐射产生高低两个工作频段,实测高低频段带宽可覆盖无线局域网络(WLAN)和微波存取全球互通(WiMAX)全部通信频段。同时,天线在各工作频段内具有良好的全向辐射特性。实测和仿真的结果基本吻合,从而验证了这种设计方法的有效性。     

Compact CPW-fed dual-band antenna

A novel coplanar waveguide (CPW) antenna is proposed for dual-band WLAN applications. It comprises a rectangular patch, a rectangular notch cut at the lower edge of the patch and a CPW transmission line. The rectangular patch together with the ground plane of the coplanar waveguide radiates at the lower frequency band, 2.4 GHz for IEEE 802.11b/g, while the rectangular notch resonates in the upper band, 5.2/5.8 GHz for IEEE 802.11a. The designed antenna is only 32 × 5 mm, which can provide stable omnidirectional radiation patterns with an average gain of 2 dBi in both the bands. The antenna is very compact and suitable for 2.4 and 5.2/5.8 GHz WLAN operations.     

矩形贴片天线基模和高次模的研究和利用

对矩形贴片天线的基模和高次模进行了研究。研究表明,矩形贴片天线的基模和高次模都具有良好的辐射性能。据此提出了同时利用天线的基模和高次模来实现高性能的大频差双频段天线的思路。本文研究为实现性能优良的双频段大频差天线提供了一种新的思路。     

The Characteristics of Iris-Fed Millimeter-Wave Rectangular Microstrip Patch Antennas

The fabrication of various iris-fed millimeter-wave rectangular microstrip patch antennas is described. A mathematical model is proposed to describe the iris-fed antenna. An iris having 15 percent of the area of the patch is used to couple energy into the antenna. Resonance of the antenna is observed to be insensitive to the size of the iris for irises up to 115 percent of the size of the patch. A study is also made of the coupling to the antenna as a function of position of the iris with respect to the transverse plane of the waveguide, the iris always being centered with respect to the patch. In general, the antenna has a VSWR in the waveguide feed of roughly 5:1 at resonance, except for the fully open waveguide which gives rise to a VSWR of 2.9:1 at resonance. Far-field antenna power patterns are observed to be quite broad with H-plane beamwidths about 130°. Maximum antenna gain observed was 4.5 dB relative to an isotropic source (dBi), with 2 dBi typical. An initial study is made of the microstrip patch antenna fed from a longitudinal waveguide wall. Results indicate that this feed structure is likely to prove valuable for microstrip patch antennas, with coupling at least as good as for the transverse-fed patch, added to the possibility of feeding multiple patches from a single waveguide.     

Dual Band Dual Polarization Directive Patch Antenna Using Rectangular Metallic Grids Metamaterial

In this letter, a kind of metamaterial superstrate based on rectangular metallic grids is presented to enhance the directivity of patch antenna at two frequency bands for two orthogonal polarizations. According to the periodic boundary condition, the influences of its important geometry parameters are investigated in detail by simulating its unit cell. It is found that the transmission peak frequency is intimately related to the size of rectangular metallic grid. Then, a dual band dual polarization patch antenna with metamaterial is studied and compared with conventional patch antenna. It is demonstrated that by introducing the proposed metamaterial superstrate, the gain of the patch antenna is improved by 9.5 dB at 14.1 GHz for x polarization and 12 dB at 15.4 GHz for y polarization, respectively.     

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.     

Bandwidth enhancement of microstrip patch antennas using coupledlines

A novel single-layer rectangular patch antenna using a coupled line feed is described. This coupled line matching technique increases the bandwidth of the patch antenna by a factor of more than 2.5 as compared to the normal edge-fed patch with the same geometrical dimension     

短路针加载三角形微带贴片天线的研究

短路针加载微带贴片天线具有较低的谐振频率,特别适用于低频便携式通信设备(如手机)中.与短路针加载矩形和圆形贴片天线相比,短路针加载三角形贴片天线具有更低的谐振频率.本文基于腔模理论,利用未加载三角形贴片天线的静态模,提出了短路针加载三角形贴片天线的理论分析方法,给出了天线谐振频率、输入阻抗及反射损耗的计算公式.数值计算与实测结果相吻合,表明这种分析方法是有效的.     

Compact active integrated antenna with transistor oscillator andline impedance transformer

A novel oscillating antenna is realised by integrating a transistor oscillator and a line impedance transformer inside a rectangular opening in a rectangular patch antenna. This active antenna exhibits stable operation and a clean spectrum. The measured copolarisation radiation patterns are not affected by the modification of the patch while the cross-polarisation levels are low     

A broad-band rectangular patch antenna with a pair of wide slits

A new broad-band design of a probe-fed rectangular patch antenna with a pair of wide slits is proposed and experimentally studied. The proposed design is with an air substrate, and experimental results show that, simply by inserting a pair of wide slits at one of the radiating edges of the rectangular patch, good impedance matching over a wide bandwidth can easily be achieved for the proposed antenna. With an air substrate of thickness about 8% of the wavelength of the center operating frequency, the proposed antenna can have an impedance bandwidth of about 24%. For frequencies within the impedance bandwidth, good radiation characteristics are also observed, with a peak antenna gain of about 7.2 dBi     

Integrated push-pull oscillating antenna

A new integrated self-oscillating patch antenna is presented. Two bipolar transistors, operating in push-pull mode, are embedded in a rectangular opening inside a rectangular patch in order to increase the power radiated by the antenna. Measurements show a high radiated power and linear frequency change with bias voltage. The radiation patterns of the patch are not affected by the introduced modifications     

一种新型的多边形超宽带印刷天线

在矩形贴片天线的基础上进行改进设计出一种新型的超宽带印刷天线,该天线由八边形的贴片和一个具有凹形槽的金属接地板组成,使天线得到了良好的超宽带阻抗匹配特性。通过数值仿真和实验测量,该结构的印刷天线在3 GHz-11 GHz频段内驻波比小于2,覆盖了超宽带天线所要求的工作频段,在H面具有良好的全向性辐射,为室内短程超宽带通信系统提供了良好的前端部件。     

一种以空气为基板的圆极化微带天线的设计

设计了一种以空气为基板的超高频（UHF）圆极化矩形微带天线。该天线通过在微带贴片四周与中心开槽,减小了天线尺寸,实现天线圆极化的性能。进一步研究了天线的参数对圆极化性能的影响,通过天线参数的优化,使天线达到了良好的圆极化性能。     

Ultra-wideband antipodal slot antenna with improved radiation performance

A novel antipodal wide-slot antenna for ultra-wideband (UWB) applications is proposed and studied in detail. The antenna is fed by a microstrip line terminated with a rectangular tuning patch. An antipodal structure is employed to improve the radiation performances. The return losses, surface E-field, current distribution, radiation patterns and gains of the antenna are numerically and experimentally investigated. Results show that the proposed antipodal antenna has an impedance bandwidth from 0.79 to 4.0?GHz, which is about 5:1. Compared with conventional rectangular wide-slot antenna, more stable radiation pattern with lower cross-polarisation level and flatter gain variation over a 3:1 bandwidth can be obtained. Thus, the proposed antenna should be more suitable for future UWB-multiple-input multiple-output applications using polarisation diversity than conventional UWB rectangular slot antennas.