Compact medium wave transmitting antennas

Increasing land costs, ever more restrictive land use regulations and the public's impression that towers are aesthetically distasteful, have led to a continuing interest in physically small transmitting antennas for use by broadcasters operating in the 535-1705 kHz medium wave band. In this paper, the author provides initial computational and empirical data for two new compact antenna system types which offer significant size reductions while providing reasonable radiation efficiency, bandwidth and stability when compared to a reference quarter-wave monopole with standard buried radial ground system consisting of 120, equally spaced, 1/4 wavelength radials.     

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.     

Compact broadband S-shaped microstrip antennas

A compact and broadband stacked S-shaped microstrip antenna with corner shorted square microstrip antenna is proposed. A broadband slotted S-shaped microstrip antenna is also proposed which does not require any parasitic patches.     

Compact uniplanar antenna for WLAN applications

A compact dual-band uniplanar antenna for operation in the 2.4/5.2/5.8 GHz WLAN/HIPERLAN2 communication bands is presented. The dual-band antenna is obtained by modifying one of the lateral strips of a slot line, thereby producing two different current paths. The antenna occupies a very small area of 14.5times16.6 mm² including the ground plane on a substrate having dielectric constant 4.4 and thickness 1.6 mm at 2.2 GHz. The antenna resonates with two bands from 2.2 to 2.52 GHz and from 5 to 10 GHz with good matching, good radiation characteristics and moderate gain     

Compact conical antennas for wide-band coverage

A broadband antenna with a vertically polarized, omnidirectional electric field is studied. The design of the antenna and its feeding system in the wide frequency range from 20 to 1000 MHz is described and the driving-point impedance determined. Also calculated are the voltage standing-wave ratio (VSWR) and the input impedance of a transmission line connected to the antenna. More efficient operation at low frequencies is obtained by adding a length of transmission line to form a resonant section with the antenna. The effect of the different properties of the earth's surface on the field pattern is treated in a companion paper     

Compact dielectric resonator antenna for WLAN applications

A new dielectric resonator antenna (DRA) with reduced size for WLAN applications is presented. The proposed antenna consists of a rectangular dielectric resonator with partial vertical and horizontal metallisations which is coupled to a microstrip line through a rectangular aperture in the ground plane. A 9.6 reduction coefficient is obtained compared to the volume of an equivalent isolated DRA. An experimental 12% bandwidth is also achieved in spite of the compact size.     

Compact low-cross-polarization horn antennas with serpentine-shaped taper

A compact horn with low cross polarization component less than -35 dB over 5% frequency bandwidth has been obtained by optimizing the taper configuration. To reduce the gain loss caused by spherical wavefront in a short length horn with a large flare angle, a serpentine-shaped taper successfully generates five higher-order modes. Such a taper configuration is represented by varying lengths of various uniform waveguides in stepwise approximation, while keeping the dimension of each step discontinuity constant. As a result, the computational time for obtaining the proposed horn is greatly reduced because scattering matrices of the step discontinuities are pre-calculated before the optimization. The verification of its high performance has been performed numerically and experimentally.     

Compact shorted variations of triangular microstrip antennas

Equilateral and triangular 30°-60°-90° microstrip antennas have been modified by shorting along the zero field to yield shorted 60 and 30°-sectoral microstrip antennas, respectively. Experimental results on these antennas are presented. The shorted 60 and 30°-sectoral antennas result in area reduction by factors of 2.5 and 5.0, respectively, compared to the equilateral triangular antenna with the same resonant frequency. The frequency is further reduced by partially shorting the curved edges of the sectoral antennas     

Compact shorted variations of circular microstrip antennas

A circular microstrip antenna has been modified by shorting along the zero field to yield shorted semi-circular and 90° sectoral microstrip antennas. Experimental results on these antennas are presented. The shorted 90° sectoral antenna results in a size reduction of four times without any significant change in performance. The area is further reduced by partially shorting one of the edges of the 90° sectoral antenna     

一种新颖的应用于无线局域网的小型化单极子天线

给出了一个新颖的三频工作的单极子天线,并可以应用于无线局域网。这个天线由对称结构和地板组成,它们分别印刷在介电常数为4.4、厚度为1.6 mm 的FR4 介质板的两面,并且采用微带线的馈电方式。这个天线有着小型化尺寸26 mm×20 mm×1.6 mm。测量结果显示,低频和高频的-10 dB 阻抗带宽分别为2.3-2.5 GHz 和4.7-6.8 GHz;这个 带宽覆盖了2.4/5.2/5.8 GHz 无线局域网工作频段。同时得到了较好的全向方向图。这个天线的低频和高频的平均增益分别为2dBi 和3.7dBi。     

Compact wideband antenna for 2.4 GHz WLAN applications

A novel compact wideband antenna for wireless local area network (WLAN) applications in the 2.4 GHz band is presented. The proposed low profile antenna of dimensions 15/spl times/14.5/spl times/1.6 mm offers 18.6% bandwidth and an average gain of /spl sim/5 dBi. The antenna can be excited directly using a 50 /spl Omega/ coaxial probe.     

一种适用于WLAN 的新型小型化双极化天线

设计了一种可工作于WLAN 2.4GHz频段的小型化双极化天线.该天线采用双层对称结构介质板,把辐射贴片四边分别切割成凸字形形状,实现了天线小型化和有效展宽天线带宽.同时在接地板开4个对称的十字形缝隙,进一步拓宽天线带宽和明显减小天线的整体尺寸并提高了天线辐射性能.由此设计制作的天线实验结果为:小于-10dB回波损耗的频段为2.37 ～ 2.59GHz,相对阻抗带宽达9.1％,端口隔离度达到了33dB,增益最大值约3.63 dBi,表明该微带天线具有宽频带和良好的辐射性能.此外,该天线结构简单紧凑,易于加工制作和集成,适合应用于移动终端.     

Compact vertical patch antenna for dual-band WLAN operation

A new compact patch antenna, which is arranged perpendicular to a circular ground plane, for WLAN operation is presented. The antenna consists mainly of one driven patch and one shorted parasitic patch, both of which wind along two concentric circles. A constructed prototype covering the 2.4 and 5 GHz WLAN bands is demonstrated. Good broadside radiation characteristics are obtained across the operating bands. Details of the proposed patch antenna 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 dual-band printed monopole antenna for WLAN application

A microstrip-fed dual-band antenna with omnidirectional radiation patterns in the azimuth plane is proposed. It can provide two separate impedance bandwidths of 0.25 GHz (2.3-2.55 GHz) and 0.85 GHz (5.1-5.95 GHz), so that it easily covers the required bandwidths for wireless local area network applications. The proposed antenna is composed of a rectangular monopole and a folded strip whose end is coupled to the monopole by a narrow gap. It occupies an area of only 6.5 times 14 mm when printed on an FR4 substrate with a thickness of 1.5 mm.     

Compact wide-band multimode antennas for MIMO and diversity

This paper presents broadband multimode antennas for multiple-input multiple-output (MIMO) and diversity applications. The antenna system is not based on spatial diversity, as usual MIMO systems, but on a combination of pattern and polarization diversity. Different modes of self-complementary, thus extremely broadband, spiral and sinuous antennas are used to decorrelate the signals. It is shown that only one antenna is necessary to receive three uncorrelated signals, thus the space required to place the MIMO antenna is very small. Simulation results and measurements of a typical indoor scenario are given.     

Mutual coupling between circular disc microstrip antennas

The mutual coupling between microstrip antennas is studied by applying the reaction theorem and the cavity model. A semianalytic formula is derived for disc antennas which takes into account the dependence on the relative angular position of the antennas, as well as on the angular feeding point poisition. Theoretical results are in good agreement with measurements.     

一种用于无线局域网的双频带印刷偶极子天线

介绍了一种运用于无线局域网的小型化印刷偶极子天线,它采用对偶极子两个臂开槽结构,使其获得双频带和小型化的特性。采用基于耦合馈电的巴伦馈电方式,使天线具有宽带匹配、结构简单、制作方便、易于集成到无线通信设备中的优点。仿真结果表明,在2.4 GHz和5.8 GHz两个频带的带宽分别为590 MHz(2.13~2.72 GHz约24.33%)和700 MHz(5.24~5.94 GHz约12.52%),而且方向图比较理想。该天线的主要优点是结构简单、体积小、低剖面、成本低、易共形,能够满足WLAN的需要。     

Compact triple band antenna for WLAN/ WiMAX applications

A low profile printed antenna with triple band operation is presented for simultaneous use in wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The antenna consists of a rectangular radiating element fed asymmetrically by a 50 Omega microstrip line and a shaped trapezoidal ground plane. Rectangular horizontal strips are attached to the radiation element to form different current paths which make the antenna resonate in WLAN and WiMAX frequency bands. The antenna operates in dipole configuration outlining overall dimensions of 38 times 30 times 0.8 mm³.     

Compact directional v.h.f. antennas

The prototype of a compact directional antenna for geophysical diagnostics from a borehole has been constructed and tested. The prototype consists of a wire monopole antenna placed next to a ferrite cylinder which loads the antenna thereby changing its characteristics. At its resonant frequency of 230 MHz, the ferrite-loaded antenna has an input resistance of 19 ?, and is physically shorter by a factor of 2.57 when compared to an unloaded monopole resonant at 230 MHz. The antenna radiation pattern is directional with a front/back ratio of 8.5 dB, and a?3 dB beamwidth of 146° at 249.6 MHz.