外 文 翻 译毕业设计题目：GPS抗干扰天线技术多频带高增益微带天线单元的仿真与设计原文1：H-MRTD simulation of dual-frequency miniature patch antenna译文1：双频微型贴片天线的H-MRTD模拟原文2：A Novel Method for Designing Dual-Frequency Slot Patch Antennas with Two Polarizations译文2：新的双频双极化开槽微带天线的设计方法H-MRTD simulation of dual-frequency miniature patch antennaYU Wen-ge1 , 2, ZHONG Xian-xin1, LI Xiao-yi1, CHEN Shuai1(1. The Key Lab for Optoelectronic Technology &Systems of Ministry of Education ,Chongqing University , Chongqing 400044 , China ;2. Basic Logistical Engineering University , Chongqing 400016 , China)Abstract: A novel MEMS dual-band patch antenna is designed using slot-loaded and short-circuited size-reduction techniques. By controlling the short-plane width , f10 and f 30 , two resonant frequencies, can be significantly reduced and the frequency radio ( f30/ f10) is tunable in the range 1.72.3.The Haar-Wavelet-Based multiresolution time domain (H-MRTD) is used for modeling and analyzing the antenna for the first time. In addition , the mathematical formulae are extended to an inhomogenous media. Numerical simulation results are compared to those achieved using the conventional 3-D finite-difference time-domain (FDTD) method and measured. It has been demonstrated that , with this technique , space discretization with only a few cells per wavelength gives accurate results , leading to a reduction of both memory requirements and computation time.Key words : dual-frequency antenna; H-MRTD method ; FDTD method ; MEMS; UPML absorbing boundary conditions1 Introduction1Recently, patch antenna research has focused on reducing the size of the patch, which is important in many commercial and military applications. It has been shown that the resonant frequency of a microstrip antenna can be significantly reduced by introducing a Short-circuited plane or a partly short-circuited plane where the electric field of the resonant mode is zero1-3 , or a short-pin near the feed probe4 . Using two stacked short-circuited patches, dual-frequency operation has been obtained5 . However, the use of a stacked geometry leads to increases in the thickness and complexity of the patch. In this paper, we demonstrate that by short-circuiting the zero potential plane of a slotted patch excited with a dominant mode (TM10), the resonant frequencies , f 10 and f 30 , of the two operating modes can be approximately halved and can even be significantly reduced by decreasing the shorted-plane width. This indicates that a large reduction in antenna size can be obtained by using the proposed design , as compared to that of a regular slot-loaded patch.The finite-difference time-domain ( FDTD )method6 is widely used for solving problems related to electromagnetism. However , there still exist many restrictive factors , such as memory shortage and CPU time , etc. we first adopted the method of the Haar-Wavelet-Based Multiresolution Time Domain ( H-MRTD)7-9with compactly supported scaling function for a full three-dimensional (3-D) wave to Yee s staggered cell to analyze and simulate the dual frequency microstrip antenna. The major advantage of the MRTD algorithms is their capability to develop real-time time and space adaptive grids through the efficient thresholding of the wavelet coefficients. Using this technique, space discretization with only a few cells per wavelength gives accurate results , leading to a reduction of both memory requirement and computation time. Associated with practical model , a uniaxial perfectly matched layer (UPML ) absorbing boundary conditions10 was developed , a three-dimensional formulation of the discrete difference equations arising from the Maxwell s system is first extended to an inhomogenous medium , it is applied to the analysis of dual-frequency miniature patch antenna.2 Dual-frequency slot-loaded patch antenna2. 1 Design of slot-loaded patch antennaThe lay out of the slot-loaded patch antenna designed in this paper is shown in Fig. 1. A single slot with dimensions L W is cut in a rectangular patch with dimensions a b with a short-circuited plane of width placed at its other side. The parameters of the antenna are a = 38mm , b = 25mm , L = 36mm ,W =1mm , d = 2mm , h = 3mm , r = 1mm , respectively. Owing to being compatible with standard IC technology , and prone to integration with other components ,silicon wafer (r = 11.7) was selected as a layer of microstrip substrate. Between the ground plate and the wafer there is a layer of foam ( r = 1.07) , which could suppress surface wave induced in the wafer substrate , as a result , the efficiency and the bandwidth of the antenna were increased , and the radiation pattern improved.Fig.1 Geometry of dual-band slot-loaded microstrip antenna2. 2 Measured resultsThe parameters of the slot antenna are selected as above mentioned. The measurements carried out on an Agilent 8720C vector network analyzer. It is then found that, by con