共查询到20条相似文献,搜索用时 15 毫秒
1.
Jiahui Fu Wan Chen Changfei Zhou Lei Zhu Qun Wu 《Applied Physics A: Materials Science & Processing》2014,116(1):327-332
In this paper, a circular polarized electronically-controlled scanning microstrip antenna array is designed, which is based on composite right left-handed transmission line (CRLH TL) and is realized by varactor diodes. Proposed electronically-controlled antenna arrays till now are always linear-polarized as the axial ratio (AR) may be spoiled by the DC feed line, especially in the CRLH TL based case. A more separated CRLH TL integrated with active lumped elements is utilized to solve the problem. The antenna array is composed of the CRLH microstrip transmission line structure and circular polarized microstrip antenna. The direction of the main lobe varies from ?1° to ?20 ° by continuously modifying the varactor diodes bias voltages from 0 to 20 V with 5 V as a step. The AR remains below 3 dB in the scanning range. The simulation and experimental results show a good consistence. 相似文献
2.
V. E. Lyubchenko V. D. Kotov E. O. Yunevich 《Radiophysics and Quantum Electronics》2003,46(8-9):717-721
Continuous electromagnetic emission from a Gunn diode built in a microstrip log-periodic antenna in the frequency range from 25 to 60 GHz is studied experimentally. The microstrip antenna was located on an insulating substrate with a thickness of about a quarter of the wavelength and with a metallized back side. It is shown that the output radiation power of such an antenna reaches 5 mW, which is over 50% of the power received from similar diodes in the waveguide cavity. The oscillation regime was varied from single-mode to noise-like, depending on the dielectric thickness and could be synchronized by external emission. Such a quasi-optical structure based on a Gunn diode is convenient for summing up powers from individual oscillators in an open resonator and is of great interest for the terahertz frequency band. 相似文献
3.
Design and prototyping of a low profile, compact square loop microstrip line fed miniature patch antenna on 1.9 mm thick ceramic-polytetrafluoroethylene (PTFE) high dielectric composite material substrate is presented in this paper. The measured ?10 dB return loss bandwidths of the antenna are 300 MHz (0.75–1.05 GHz) and 800 MHz (2.4–3.2 GHz) with 3.4 dBi, 8.86 dBi and 7.42 dBi at 900 MHz, 2.5 GHz and 3.0 GHz, respectively. The measured symmetric and almost stable radiation pattern makes the proposed antenna suitable for RFID, GSM, ZIGBEE, WBAN, LR-WPAN etc. integrated mobile devices. 相似文献
4.
5.
《Waves in Random and Complex Media》2013,23(2):235-242
AbstractThis paper presents dual-band wearable antenna using split-ring resonator (SRR). The SRR is placed near patch and feed line. SRR makes a major contribution to the first operating band (2.32 GHz), but it has a minor effect on the second operating band (3.5 GHz). The wearable antenna at 3.5 GHz (without using SRR) is also presented for comparison sake. The simulation results are analyzed and compared with the measured results, which shows that there is a good agreement between them. 相似文献
6.
M. Habib Ullah M. T. Islam J. S. Mandeep N. Misran 《Applied Physics A: Materials Science & Processing》2013,110(1):199-205
The design and prototyping of a new double L-shaped patch antenna on substrate of available low cost polymer resin composite material is presented. The designed microstrip line fed compact antenna consists of a planar double L-shaped slotted radiating patch, 1.6 mm thick substrate and ground plane. The proposed small antenna was designed and analyzed using a finite-element method-based, commercially available, high frequency structure simulator, and fabricated on a printed circuit board. The measured ?10 dB return loss bandwidths were 220 MHz and 650 MHz at 4.85 GHz and 8.10 GHz center frequencies. The corresponding symmetric and almost steady radiation patterns have peak gains of 7.6 dBi and 4.1 dBi, making the proposed antenna suitable for C and × band wireless applications, especially for WLANs, mobiles and satellites. The radiation efficiency, input impedance and current distribution of the proposed antenna were also analyzed. 相似文献
7.
针对通信与雷达系统对双极化与宽带天线的要求,提出了一种基于带状线馈电的双极化蝶形天线。通过两对互相正交的蝶形阵子实现了天线的双极化,并采用一种新型的微带线转异面带状线的巴伦给两对正交蝶形阵子平衡馈电。异面带状线为平衡传输线,满足了蝶形阵子对于平衡馈电的要求。在馈电点处由同轴线对微带线馈电,经渐变微带线转化为异面带状线,最后由两组异面带状线给两对正交蝶形阵子馈电。测得该天线实现了69.23%的阻抗带宽,在6.8~14GHz频带内电压驻波比(VSWR)小于2。为使天线单向辐射且改善天线增益,将天线放置于反射吸收腔内。测得天线在6.8~18GHz的频宽内VSWR基本小于3,天线增益在8~12GHz频带内大于0.11dB,天线前后瓣比大于15dB。因此,所提出的双极化蝶形天线可用于宽带通信系统中。 相似文献
8.
Shunlian Chai Demiao Yao Naichang Yuan Junjie Mao 《International Journal of Infrared and Millimeter Waves》1997,18(6):1299-1306
A novel conical microstrip antenna with uniform substrate is investigated. The far field radiation patterns of wraparound
microstrip antennas mounted on such a structure are studied theoretically. Results for a wraparound antenna of half-wavelength
in width excited by TM01 are given, which are verified accurate and efficient by the ones of wraparound cylindrical antennas when the cone angle is
very small. 相似文献
9.
In this paper, spirals are arranged periodically on the surface of the substrate, making a left-handed material (LHM) with a near-zero index of refraction. A radiation patch is etched on the surface of this substrate, making an antenna. The finite difference time domain method is used to study the effect of this LHM with a near-zero index of refraction on the microstrip. At f=13.78 GHz, the equivalent permittivity and permeability of the proposed spiral materials are both negative; at f=28.02 GHz, the equivalent permittivity and permeability are both negative and the refraction index is near zero. Compared with conventional microstrip antenna, the radiation gain of the antenna is much higher and the return loss is much lower due to the near-zero-index effect. 相似文献
10.
C. F. L. Vasconcelos M. R. M. L. Albuquerque G. M. F. Freitas A. G. D’Assunção 《Applied Physics A: Materials Science & Processing》2013,111(4):1085-1089
The annular ring microstrip antennas on metamaterial substrates are modeled and analyzed using full-wave analysis in conjunction with Ansoft HFSSTM. The influence of the permeability tensor of the split ring resonator medium on the resonant characteristics of the antenna is considered. Numerical results for typical resonant frequency behavior and return loss are presented as function of the metamaterial properties and antenna structural parameters. 相似文献
11.
A. Ye. Svezhentsev 《Radiophysics and Quantum Electronics》2008,51(3):200-209
We consider the problem of excitation of a cylindrical microstrip antenna fed by a cylindrical microstrip line. The problem
has been solved by the moments method in the spatial domain using a new representation of the Green’s function. In the model
proposed, a cylindrical microstrip line of finite length is attached to the patch and is considered as its part. The so-called
lumped delta generator is chosen as the excitation source. At the first stage, current distributions on the patch and in the
microstrip line are found by solution of the integral equation. Then using the well-known relations of the transmission-line
theory and the equivalent-scheme method, we calculate the reflection coefficient in the microstrip line and the antenna input
impedance. Patches of different shapes are discussed.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 3, pp. 223–233, March 2008. 相似文献
12.
《Waves in Random and Complex Media》2013,23(2):218-226
A quarter wavelength high-Q resonator based on the well-known split-ring resonator (SRR) element in series configuration on a microstrip line is proposed in this letter. The small size is achieved by working at the quasi-static resonant frequency of the SRR. A relatively high value of unloaded-Q of 137 is achieved, which is considerably higher than other microstrip resonators like closed-loop resonators. An equivalent lumped-element circuit model for this new resonator and the ground plane influence in the unloaded-Q particle are studied. A good agreement between simulation, equivalent circuit, and experimental results is shown and discussed, leading to a simple and effective design. 相似文献
13.
Giuliano F. Bastista Oliveira José Elesbão C. Neto Humberto C. Chaves Fernandes 《International Journal of Infrared and Millimeter Waves》2003,24(7):1159-1169
For the microstrip patch resonator, as a planar antenna of a microstrip, a set of equations that represents the electromagnetic fields in the x and z direction as function of the electric field in the y direction are obtained applying the TTL method. This method is very suitable at microwave and antenna applications, and gives accurate complex resonant frequency, which contributes definitively to obtain higher precision antenna parameters. For each type of array is calculated the array factor, considering the excitation, phase and the relative displacement between the elements as well as the dimensions and number of elements. 相似文献
14.
《Waves in Random and Complex Media》2013,23(1):19-34
We have reported multiband meandered truncated square microstrip patch antenna loaded with metamaterial in this paper. The patch is meandered at edges and truncated at corners. Metamaterials are composite materials that provide some unique characteristics, which are not available in nature. The inclusion of these structures allows simultaneous operation over several frequencies. The antenna is designed to function in multiple bands in the frequency range of 0.5–2.0 GHz. The antenna has five working frequency bands and its center frequencies are 660, 950, 1330, 1580, and 1750 MHz for design 1. We have obtained design 2 by changing the slit size and the design has five working frequency bands. Design results are obtained by a high frequency structure simulator which is used for simulating microwave passive components. 相似文献
15.
基于树枝状金属结构单元模型的电磁特性,设计了一种双面刻有树枝状金属结构单元阵列的负磁导率介质材料,并将这种介质材料作为微带天线的基板,制备了中心工作频率为2.64GHz的树枝状负磁导率材料微带天线.仿真和测量结果都表明:相比普通微带天线,树枝状负磁导率材料微带天线的性能得到了明显改善,定向性得到了提高,E面和H面的3dB角分别收缩了18°和13°,增益提高了2.19dB,相当于有效辐射功率提高了65%.说明利用负磁导率材料作为微带天线的基板,可以明显改善微带天线的性能.
关键词:
树枝状结构
微带天线
负磁导率
增益 相似文献
16.
Xiao-Jun Tang Shao-qiu Xiao Bing-Zhong Wang Jianpeng Wang 《International Journal of Infrared and Millimeter Waves》2007,28(4):275-281
This paper proposes a new wideband W-band substrate integrated waveguide (SIW) cavity-backed slot (CBS) antenna. The SIW cavity
suppresses the backward radiation and ensures this antenna have a very low profile (only about 4% of the operating wavelength).
Several techniques, such as slot resonator with semicircular end, quarter-wavelength microstrip resonator, are introduced
to improve impedance matching. The studied results demonstrate that this antenna has wide operating bandwidth in 54.3–67 GHz
(about 20.9% of the fractional bandwidth), unidirectional radiation pattern and good linear polarization characteristic. These
properties are very suitable for RF front-end system-on-package (SoP) design in millimeter wave wireless communication systems.
This work was supported by the National Nature Science Foundation of China (60501011, 90505001), the Specialized Research
Fund for the Doctoral Program of Higher Education of China (No. 20060614005) and the Creative Research Team Program of UESTC. 相似文献
17.
设计了一种简单的双面单方环结构左手材料,在4.8–5.25 GHz频率范围内该材料的等效介电常数和等效磁导率同时为负.将此单方环左手材料作为覆盖层,置于中心工作频率为5.0 GHz的微带天线之上. 仿真和实验研究表明:相对普通微带天线而言,覆层微带天线的性能得到了明显改善, E面和H面的半功率波束宽度分别收缩了25°和20°,定向性得到了提高, 5 GHz处的增益提高了3 dB, -10 dB带宽增加了600 MHz.
关键词:
单方环结构
左手材料
微带天线 相似文献
18.
设计了一种工作于X波段的基于共享孔径Fabry-Perot(F-P)谐振腔结构的宽带高增益磁电偶极子微带天线,并设计了三种不同尺寸的双层频率选择表面(FSS)单元,通过共享孔径布阵组成了超材料覆层.利用三种FSS单元的相位补偿特性,有效拓展了覆层天线的增益带宽.实测和仿真结果均表明,加载超材料覆层后,磁电偶极子天线在7.8—12.3 GHz内S_(11)-10 d B,相对带宽达到44.7%,覆盖整个X波段.天线增益在7.9—12.1 GHz内均有明显的提高,最大提高了7 d B.相较于传统的F-P谐振腔结构覆层天线,设计的基于共享孔径的F-P谐振型超材料覆层天线能够明显拓展天线增益带宽,在新型宽带高增益天线设计方面具有广阔的应用前景. 相似文献
19.
设计了一种高吸波率、宽入射角、无表面损耗层的超材料吸波体, 并将其用于微带天线的带内雷达散射截面(radar cross section, RCS)减缩.实验结果表明: 设计的吸波体的厚度为0.3 mm, 吸波率达99.9%, 相比普通微带天线, 加载该吸波体后的天线在工作频带内法向RCS减缩都在3 dB以上, 最大减缩16.7 dB, 单站RCS在-30°–+30° 角域、双站RCS在-90°–+90°角域减缩超过3 dB, 且天线辐射性能保持不变. 证实了该吸波体具有良好的吸波效果, 可以应用于微带天线的带内隐身.
关键词:
超材料吸波体
微带天线
雷达散射截面 相似文献