Mutual coupling reduction of low-profile monopole antennas onhigh-impedance ground plane

The mutual coupling effects of flush-mounted (horizontal) monopole antennas on high-impedance ground planes (HIP) have been measured. Experiments of horizontal monopoles on HIP with a bandgap centred at 4.7 GHz show that the interference between two adjacent elements is stronger compared to those on a regular metal ground plane due to special properties of HIP. A technique using a combination of HIP and thin metal strip is proven to reduce the mutual coupling by ~6 dB. Similar results have been obtained for the horizontal monopoles on HIP with a bandgap centre at 17 GHz     

A low-profile planar monopole antenna for multiband operation of mobile handsets

A novel planar monopole antenna is proposed. It has a very low profile (antenna height less than 0.04 times the operating wavelength in free space) and is capable of multiband operation. The proposed antenna has a planar rectangular radiating patch in which a folded slit is inserted at the patch's bottom edge. The folded slit separates the rectangular patch into two subpatches, one smaller inner subpatch encircled by the larger outer one. The proposed antenna is then operated with the inner subpatch resonating as a quarter-wavelength structure and the outer one resonating as both a quarter-wavelength and a half-wavelength structure. The proposed antenna, 12 mm high and 30 mm wide, has been constructed, and the obtained bandwidths cover the global system for mobile communication (890-960 MHz), digital communication system (1710-1880 MHz), personal communication system (1850-1990 MHz), and universal mobile telecommunication system (1920-2170 MHz) bands. Details of the proposed design and obtained experimental results are presented and discussed.     

Planar monopole in wrapped structure for low-profile GSM/DCS mobilephone antenna

A novel planar monopole consisting of two sub-patches and wrapped into a compact structure with a height of 10 mm for 900 and 1800 MHz operation is presented. The antenna can be mounted on the top portion of a mobile phone housing a small distance (4 mm) from the ground plane, resulting in a low profile of 14 mm (about 4.2% of the wavelength at 900 MHz), and the obtained 10 dB return-loss impedance bandwidths cover the GSM (880-860 MHz) and DCS (1710-1880 MHz) bands     

Wide-band planar monopole antennas

The circular disc monopole (CDM) antenna has been reported to yield wide-impedance bandwidth. Experiments have been carried out on a CDM that has twice the diameter of the reported disc with similar results. New configurations are proposed such as elliptical (with different ellipticity ratios), square, rectangular, and hexagonal disc monopole antennas. A simple formula is proposed to predict the frequency corresponding to the lower edge of the bandwidth for each of these configurations. The elliptical disc monopole (EDM) with ellipticity ratio of 1.1 yields the maximum bandwidth from 1.21 GHz to more than 13 GHz for voltage standing wave ratio (VSWR)<2     

Stacking resonators to increase the bandwidth of low-profile antennas

A method of increasing the bandwidth of low-profile cavity-hacked slot and microstrip patch antennas without appreciably adding to the antenna dimensions is presented. This idea incorporates the stacking of structures which have close resonant frequencies. Energy is coupled between cavities via carefully placed slots in the common wall. An approximate two-and-a-half fold increase in input impedance bandwidth has been observed for a certain cavity-backed slot antenna.     

Patch antenna equivalent to simple monopole

Properties of a circular patch antenna with radiation characteristics similar to those of a resonant monopole are presented. The TM₀₁ mode excited patch on a small ground plane radiates a null on boresight and is easy to match to a 50 Ω line. Applications include mobile vehicle applications and wireless LANs     

A low-profile rectangular dielectric-resonator antenna

A rectangular dielectric-resonator antenna (DRA) with a very low profile (length-to-height ratio ≈6) is presented. This aperture-coupled antenna is almost perfectly matched to the 50 Ω input and radiates like a magnetic dipole at 11.6 GHz. It is also well matched at 13.0 GHz, but the pattern is more directional due to the influence of a higher order mode. Theoretical antenna patterns, obtained using the FDTD method, compare well with measured patterns in the E and H planes     

Multiband multiple ring monopole antennas

This paper proposes two novel designs of a multiband antenna using multiple rings. The first design consists of a set of self-similar circular rings. This is an alternative to the recently reported triangular fractal Sierpinski gasket monopole antenna, and comparison is made to this and the circular disk monopole antenna. The second design is realized by varying the shape of the circular structure to an elliptical one. Larger bandwidth and improved patterns are achieved. In comparison to the circular disk, improved radiation pattern control at higher operating bands, due to the discrete structure of the multiple rings, is shown by numerical and experimental results. The bandwidth is significantly larger than the Fractal Sierpinski gasket and Parany monopole.     

Retro-transceiver array using monopole antennas

In this paper, we show how a self-tracking antenna array constructed using λ/4 monopoles can be constructed, which is capable of receiving with gain over an entire 360° azimuthal cut. It is also shown how the self-tracking receive unit can be used in conjunction with a self-phased transmitter so that self-steered spatially selective receive and transmit functions can be formed simultaneously. The resulting array is capable of maintaining spatially selective receive and transmit functions to a roaming target without prior knowledge of its physical location     

Wideband double-fed planar monopole antennas

Planar monopole antennas with multiple feed points are proposed to improve pattern and impedance bandwidth. A square planar monopole antenna including two feed points and a bevelled variant are designed. These antennas exhibit an excellent performance compared to existing planar monopoles     

Optoelectronically reconfigurable monopole antenna

A monopole antenna is reconfigured for 200 or 375 MHz bands by optoelectronically switching two segments together. Light levels of much less than 1 mW significantly change the antenna pattern and gain.<>     

Wideband tri-plate monopole antenna

A novel wideband tri-plate monopole antenna comprising three folded rectangular plates spaced by 120/spl deg/ and connected together at the antenna's central axis is presented. The antenna occupies a small cross-sectional area of 10 mm in diameter and yet provides a large bandwidth of >10 GHz (about 2.7-12.9 GHz here). In addition, the antenna shows improved omnidirectional radiation patterns across the passband.     

宽带平面单极天线

提出了一种宽带平面单极天线,其辐射单元为底部具有斜切角的矩形铜片,馈电点偏离辐射单元的中心位置,斜切角和不对称馈电的应用有效地扩展了带宽.用Ansoft HFSS软件对天线尺寸、斜切角和馈电点位置等参数对天线特性的影响作了分析,给出了这些参数的最佳值,并根据这些最佳参数制作了天线样机.以电压驻波比小于3.5:1为标准,实测得到的天线带宽为70～3000 MHz.电压驻波比和方向图的测量结果与仿真结果吻合较好.     

Multi-circular loop monopole antenna

A novel multi-band multiple circular loop monopole antenna is presented. The three outer loops have a size ratio of 2 while the feed monopole is a disc, resulting in a quasi-log periodic performance. A method for controlling the radiation pattern, which gives better results than the circular disc monopole at higher operating frequencies, is presented. The proposed antenna performance is also compared with that of the fractal Sierpinski gasket monopole     

快速计算套筒单极子天线

利用矩量法分析计算套筒单极子天线的电性能参数。采用与实际天线较为接近的矩量法分析模型和一种新的粗圆柱线天线快速精确计算模型,大大提高了分析计算的精度;引入「Ｚ」矩阵插值法,提高了分析计算的速度。将该方法与最优化技术相结合,设计出一付工作在２００～７００ＭＨｚ频段、ＶＳＷＲ〈２．６、增益Ｇ〉５．１ｄｂ的实用套筒单极子天线,理论分析与实验测试吻合良好,从而说明了该方法的有效性和实用性。     

基于耦合加载的低剖面天线设计

设计了一种小型化双频天线。通过在单极子天线上引入寄生耦合的方法,即在单极子顶部引入耦合加载板,既保证了单极子天线的辐射全向性又减小了电小天线的分布电容,从而使该天线具有宽频带、低剖面特性。采用仿真软件Ansoft HFSS进行仿真和优化,优化结果表明:该天线工作频率为824～960MHz/1 710～2 690MHz(驻波比小于等于2)。根据仿真模型制作了一款天线,实测驻波带宽可达811～1 050MHz/1 580～2 660MHz,且在水平面内辐射全向方向图。该天线在限制尺寸的情况下有效地展宽了带宽。     

Spline-based geometry for printed monopole antennas

A novel Bezier spline-based geometry for printed monopole antennas is presented. Quadratic curves are used to describe the outline of the radiating element. The geometry is optimised by a genetic algorithm. A small number of control points are used to define the geometry, ensuring a small search space for the GA. The resulting antenna has an impedance bandwidth from 1.44 to 14.7 GHz     

UWB Metamaterial-based miniaturized planar monopole antennas

In this paper, ultra wide band (UWB) metamterial based compact planar antennas have been designed and experimentally verified. Four novel unit cells have been realized and each unit cell dispersion characteristics are numerically calculated which follows CRLH-TL properties. These four CRLH-TL unit cells are loaded into monopole antennas which result, four open-ended MTM antennas respectively. Further, a novel via free version of CRLH-TL unit cells have been designed, which increases the fabrication flexibility. The compactness has been achieved by realizing ZOR (zeroth order resonance) mode and its bandwidth is increased by realizing small shunt capacitance and large shunt inductance. Further, by optimizing CRLH-TL unit cells, two closely spaced zeroth-order and first-order resonance modes are merged into a single pass band, which gives wide bandwidth. The each proposed antenna has a compact dimension of 0.27 λ₀ × 0.19 λ₀ × 0.02 λ₀ (22 × 15 × 1.6 mm³), where λ₀ is a free space wavelength at 3.8 GHz. The four proposed antennas have S₁₁ < −10 dB impedance bandwidths of 8.4 GHz, 8.5 GHz, 8.2 GHz and 8.3 GHz respectively. The optimum gain, good efficiency, desired radiation characteristics in frequency domain analysis and less distortion of waves in time domain analysis have been achieved for proposed antennas, which are most suitable for UWB applications. The CST-MWS has been used for the parametric study of the proposed antennas. A good agreement has been observed between simulated and experimental results.     

Multiple meander strip monopole antenna

A novel multiple meander strip monopole antenna is presented. By iteratively meandering the vertical strip, compactness and broadband characteristics for the monopole antenna were achieved simultaneously. The designed monopole antenna with a radiation element volume of 14/spl times/14/spl times/14 mm/sup 3/ has the measured bandwidth ratio of 3.87:1, from 2.83 to 10.96 GHz for VSWR/spl les/2, with fairly frequency-insensitive omni-directional radiation characteristics.     

A CPW-fed dual-frequency monopole antenna

A new dual-frequency design of coplanar waveguide (CPW)-fed monopole antenna is proposed and experimentally studied. The proposed antenna utilizes the advantages of the CPW line to simplify the structure of the antenna into a single metallic level, thereby making easier the integration with the microwave integrated circuits. The two operating modes of the proposed antenna are associated with various lengths of two monopoles, in which the longer monopole works for the first resonant mode and the shorter monopole works for the second mode. Moreover, by increasing the width of the longer monopole, a broadband dual-frequency operation is demonstrated. Experimental results show that the impedance bandwidth, determined from 10-dB return loss, of the two operating frequencies can both be greater than 14%. Details of the experimental results are presented and discussed.