共查询到19条相似文献,搜索用时 78 毫秒
1.
为解决在VHF和UHF频段内的紧耦合偶极子阵列(tightly coupled dipole array, TCDA)天线馈电网络设计困难、不利于工程化的问题,提出一款采用新型宽带同轴馈电的具有低剖面、双极化特点的TCDA天线设计方案. 该天线采用双偶极子单元结构,由二阶Wilkinson功分器和新型宽带同轴巴伦共同组成馈电网络,接地短路枝节抑制E面共模谐振,频率选择表面(frequency selective surface, FSS)层抑制H面扫描失配. 通过ADS-HFSS联合进行高效的电磁仿真,结果表明,该TCDA在110~500 MHz内电压驻波比(voltage standing wave ratio, VSWR)典型值<2,±45°扫描角度VSWR典型值<2.5,剖面高度小于0.1\t\t\t\t\t$ {\\lambda }_{\\mathrm{l}\\mathrm{o}\\mathrm{w}} $. 该天线具有剖面低、易于全金属化的特点,为超短波频段TCDA的工程实际化提供了一种可靠的方法. 相似文献
2.
3.
4.
提高相位干涉仪测向精度与改善测角范围的探讨 总被引:5,自引:0,他引:5
简单介绍单基线相位干涉仪测向的基本原理,针对其测向范围与测向精度的矛盾,利用多基线相位干涉仪即可解决这一矛盾,既能增大测向范围,又可以达到高的测向精度,关键在于如何解相位模糊问题,文章给出一种解模糊的方法。 相似文献
5.
分析了干涉仪的天线阵元极化差异导致测角误差的原理,指出该项误差是干涉仪在工程应用中最大的误差来源,提出使用基于数字处理的合成阵元代替常规阵元消除该误差的方法。合成阵元的权值表用离线方式生成,干涉仪工作时以测得的信号频率为依据在权值表中查找对应的权值实时进行阵元合成,消除阵元间的极化差异和测角误差。 相似文献
6.
本文详细地介绍了机载干涉仪测向系统使用的平面螺旋天线在2-8GHz频段人的相位特性的研究结果,还重点介绍了影响天线相位特性的关键部件-平衡器的相位特性和一组天线之间的相对相位差。 相似文献
8.
设计并加工测试了一款双面Vivaldi天线.通过结构优化, 提高了馈电效率和阻抗带宽, 并在组阵后显著降低了阵元间的互耦.实测结果表明该天线可以实现在2~8 GHz的频带内回波损耗(Return Loss, RL)小于-10 dB, 平均增益大于5 dBi.并采用“交错排列”的思路, 将所设计的双面Vivaldi天线组成超宽带阵列.此种方式可以有效解决天线尺寸和最佳阵列间距之间的矛盾, 进而抑制栅瓣, 增大波束扫描角范围.仿真分析表明, 在4~6 GHz时, E面交错阵列比普通一维阵列的扫描角范围提高20°左右. 相似文献
9.
相位干涉仪中均匀阵列测向精度研究 总被引:1,自引:0,他引:1
对相位干涉仪体制中所使用的两种均匀阵列进行了研究,对阵列的测向算法进行了改进,并用matlab软件进行了计算机仿真,仿真结果表明在同等条件下,虽然平面阵的算法较复杂,但是测量误差更小,测向精度更高,具有更好的性能。 相似文献
10.
11.
《Electronics letters》2008,44(21):1231-1233
A compact ultra-wideband printed planar antenna with tri-band notched characteristic is presented. Two different types of slots are used to obtain tri-band notched characteristic. By using a U-slot defected ground structure, a notched band, 5?6 GHz for WLAN, is achieved. An H-shaped slot is etched on the radiating patch to obtain another two notched bands at 3.3?3.7 GHz for WiMAX and 7.2 GHz for some C-band satellite communication systems. The proposed antenna yields an impedance bandwidth of 3.1?10.6 GHz with VSWR , 2, except the notched bands. The antenna is successfully simulated and measured, showing tri-band notched characteristic can be obtained by using two different slots. 相似文献
12.
单脉冲定向技术是目前最准确的电子定向技术之一, 被广泛应用于微波毫米波跟踪、监视、通信、测量、天文观测等系统.为了保护雷达天线免受环境的影响, 许多单脉冲天线都采用天线罩, 这会对单脉冲天线方向图的极化结构产生影响, 另外, 有意的电子欺骗干扰如交叉极化干扰会对定向性能产生较大影响.文章以雷达导引头普遍采用的X波段抛物反射面幅度比较单脉冲天线为对象, 分析了抛物面结构、初级馈源特性、天线罩引起交叉极化分量的机理, 建立了典型物理参数下的计算模型, 在Ludwig第三定义下对加入天线罩前后单脉冲天线交叉极化特性进行仿真, 综合考虑了天线几何形状、偏置结构、天线扫描等因素对极化特性的影响.结果表明:多种因素会引起单脉冲天线显著的去极化效应, 复杂的方向图极化结构使得单脉冲雷达导引头的定向精度敏感于电波极化方式, 这为进一步开展交叉极化对抗单脉冲跟踪技术研究提供了重要理论基础. 相似文献
13.
A simple and compact ultra-wideband microstrip-fed planar antenna with dual bandstop characteristic is presented. By using a U-slot defected ground structure (DGS) in the feedline, a stopband of 600 MHz (from 5.45 to 6.05 GHz) for band rejection of WLAN is achieved. To obtain another stopband, an arched slot is etched on the radiating patch. Experimental results show that the designed antenna, with a compact size of 30 times 24.5 mm, has an impedance bandwidth of 2.8-11 GHz for voltage standing wave ratio (VSWR) less than 2, except two frequency stop-bands of 3.5-4.25 GHz and 5.45- 6.05 GHz. Moreover, the antenna has good omnidirectional radiation patterns in the H-plane. 相似文献
14.
The characteristic polarization states and the equi-power curves 总被引:1,自引:0,他引:1
Jian Yang Yamaguchi Y. Yamada H. Czyz Z.H. Boerner W.-M. Mott H. Luneburg E. Yingning Peng 《Geoscience and Remote Sensing, IEEE Transactions on》2002,40(2):305-313
Characteristic polarization state theory is restudied for the symmetric coherent Sinclair scattering matrix case. First, the geometric relations of the characteristic polarization states on the Poincare sphere are derived. Based on these relations, simple formulas are given for all of the characteristic polarization states of this Sinclair matrix in Stokes vector form. From the formulation, it is clear that the CO-POL Nulls are fundamental characteristic polarization states for the symmetric coherent Sinclair scattering matrix case, in that the others can straightforwardly be obtained from the Stokes vectors of the CO-POL Nulls. For further study of the characteristic polarization state and the distribution of the received powers on the Poincare sphere, the authors introduce the concept of the equi-power curve. It is defined as the curve on the Poincare sphere on which the received powers in some defined channel have the same value. They deal with the characteristics of the equi-power curves for various special cases. In addition, they show how the characteristic polarization states are generated by the equi-power curves. It is demonstrated that the characteristic polarization states can usually be regarded as the points of contact of the Poincare sphere and a conicoid representing a power-related quadratic form. This leads to a new method to introduce the characteristic polarization states 相似文献
15.
A novel and compact ultra-wideband printed antenna with band-rejection characteristic is proposed. By cutting an L-shaped notch on the radiating patch, the impedance bandwidth of the proposed antenna can be enhanced. In addition, a C-shaped slot is introduced to obtain the band-rejection operation of the antenna. The antenna, with compact size of 15.5/spl times/21 mm including the ground plane, operates over 3.08-10.97 GHz and has the rejected band from 5.03 to 5.91 GHz. 相似文献
16.
E. V. Balzovskii Yu. I. Buyanov V. I. Koshelev 《Journal of Communications Technology and Electronics》2010,55(2):172-180
The results of investigation of a 4 × 4 ultra-wideband dual polarization receiving antenna array designed for investiagtion
of the polarization structure of nanosecond and subnanosecond electromagnetic pulses are presented. The elements of this antenna
array are the crossed dipoles whose arms are loaded with single-stage FET amplifiers. The results of measurements of the patterns,
the effective length, and the wave-forms of the recorded pulses are presented for different values of the array interelement
spacing and the directions of arrival of radiation. 相似文献
17.
18.
19.
《Electronics letters》2008,44(19):1106-1107
A compact ultra-wideband microstrip-fed planar antenna with dual band-notch characteristic is presented. Two notched frequency bands are achieved by embedding an E-slot in the radiation patch and a U-slot defected ground structure in the feeding line. Moreover, the two notched bands can be controlled by adjusting the length of the corresponding slot. Experimental results show that the proposed antenna, with compact size of 35 x 14 mm, has an impedance bandwidth of 2.87-10.91 GHz for a voltage standing-wave ratio less than 2, except two frequency notched bands of 3.49-4.12 and 5.66-6.43 GHz. 相似文献