Efficient analysis of microwave passive structures using 3-D envelope-finite element (EVFE).pdf
《Efficient analysis of microwave passive structures using 3-D envelope-finite element (EVFE).pdf》由会员分享,可在线阅读,更多相关《Efficient analysis of microwave passive structures using 3-D envelope-finite element (EVFE).pdf(7页珍藏版)》请在三一文库上搜索。
1、IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 50, NO. 12, DECEMBER 20022721 Efficient Analysis of Microwave Passive Structures Using 3-D Envelope-Finite Element (EVFE) Hsiao-Ping Tsai, Student Member, IEEE, Yuanxun Wang, Member, IEEE, and Tatsuo Itoh, Fellow, IEEE AbstractA three-dimens
2、ional envelope-finite element (EVFE) technique is proposed to solve the transient responses of general microwave passive structures. EVFE simulates the signal envelope rather than the original signal waveform by de-embedding the carrier from the time-domain wave equation. The sampling rate of the ti
3、me-domain waveform is only governed by the Nyquist rate of the envelope, rather than that of the carrier in traditional time-domain simulators. Compared to traditional finite-element time-domain (FETD) methods, the computational cost can be dramatically reduced when the signal envelope-to-carrier ra
4、tio is very small. It also provides much higher computational efficiency than frequency-domain finite-element methods for simulating frequency responses over certain bandwidth. This technique is applied to solve a waveguide structure with a dielectric post discontinuity and a microstrip patch antenn
5、a. The accuracy and efficiency is demonstrated and compared with traditional unconditionally stable FETD methods. Index TermsEnvelope simulation, finite-element time-domain method, full-wave approach, time-domain modeling. I. INTRODUCTION A S THE COMPLEXITY of microwave circuits and operating freque
6、ncies increase, development of com- puter-aided design (CAD) tools to efficiently and accurately predict performance of high-frequency circuits is in higher demand. Most commercial design tools are based on a circuit approach, in which the-parameter matrix and the har- monic-balance method are appli
7、ed by dividing the circuit into small elements and cascading the characteristic of each element to obtain the overall system performance. Consequently, the electromagnetic (EM) effects such as surface wave leakage, coupling between closely spaced components or subsystems, and packaging effects are i
8、gnored or approximated at best. Successful high-frequency circuit design requires full-wave analysis, which includes electromagnetic effects by solving Maxwells equations and taking into account the above EM interaction. Most full-wave numerical methods for characterizing EM effects require extensiv
9、e computer resources. In the last few years, there has been a significant improvement in both com- puter resources and EM simulation techniques so that the use of full-wave EM simulators becomes economically viable. Commercially available EM simulators consist mainly of two Manuscript received April
10、 5, 2002; revised August 21, 2002. H.-P. Tsai is with Mindspeed Technologies, Newport Beach, CA 92660 USA (e-mail: hsptsaiieee.org). Y. Wang and T. Itoh are with the Department of Electrical Engineering, Uni- versity of California at Los Angeles, Los Angeles, CA 90095 USA (e-mail: ywangee.ucla.edu;
11、itohee.ucla.edu). Digital Object Identifier 10.1109/TMTT.2002.805190 types: frequency domain and time domain. The first includes the 2.5-D solvers based on the method of moments and the three-dimensional (3-D) solvers based on the finite-element method (FEM). However, with the increasing size of sys
12、tems with complex spectral behavior, solving problems at many discrete frequency points with sufficient resolution can be very time consuming. The second type of EM simulator is the finite-difference time-domain (FDTD) technique. The FDTD method, first introduced by Yee 1, has been the most popular
13、method for the simulation of the transient EM wave phenomena for the past few decades. The FDTD method shows great promise in its flexibility in handling a variety of circuit configurations, such as filters, microstrip transitions, bond wires, bridges, etc. 2, 3. It was later successfully implemente
14、d to solve several nonlinear microwave circuits, including crosstalk and packaging effects 4, 5. The most important benefit of time-domain analysis is that a broad-band pulse can be applied as the excitation so that broad-band fre- quency-dependent scattering parameters can be calculated from a sing
15、le computation. Despite its programming simplicity, it has suffered from the staircase approximation when the method is applied to geometries with curvature and/or fine features 6. Although less popular, the finite-element time-domain (FETD) method has some important advantages over the standard FDT
16、D method. Since the grid is unstructured, it offers superior versatility in modeling complex geometries. Furthermore, the use of vector elements 7 provides a very natural way of enforcing tangential continuity to the electric field and normal continuity to the magnetic flux density at material inter
17、faces, thus further enhancing modeling accuracy. Several variants of FETD have been proposed and implemented in 813. Wongs technique 12 has been extended by Chang et al. 14 and provided solutions of a microwave amplifier and an injection-locked oscillator. Among those FETD techniques, the time deriv
18、atives were approximated by a difference scheme, resulting in an explicit time-domain scheme. Therefore, the methods described above are only conditionally stable with time steps which are typically equal to, or smaller than, those imposed by the FDTD technique. An implicit time-domain scheme, on th
19、e other hand, involving one-time matrix inversion and field updating of every time step, has been developed by Gedney and Navsariwala 15 for the solution of the second-order electric-field Maxwells equations. For the field approximation, the use of the one-form Whitney element 7 gives degrees of fre
20、edom associated with its edges because it only enforces tangential continuity of vector fields. The second-order differential time-dependent formula employs a time-integration method based on the NewmarkBeta method 0018-9480/02$17.00 2002 IEEE 2722IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
21、, VOL. 50, NO. 12, DECEMBER 2002 16. With appropriate values of the parameters controlling the accuracy and the stability of the scheme, the Newmark method yields an unconditionally stable scheme with second-order accuracy 15, 17. The extended technique, called the un- conditionally stable extended
22、(USE) FETD method 18, was implemented to solve a microwave amplifier and illustrated a significant improvement in computational efficiency over the conditionally stable FETD method in terms of CPU time. The envelope finite-element (EVFE) technique recently proposedby Wang etal. 19 isaneven moreeffic
23、ient full-wave time-domainmodelingscheme.Whentheunconditionallystable FETD scheme is applied to solve a problem which has a much narrower signal bandwidth than the carrier frequency, the time step is still constrained by the maximum operating frequency, andmuchcomputationtimeisunnecessarilywasted.By
24、adapting the concept of envelope simulation, this computation expense can be saved. The circuit envelope technique has been recently introduced in 20 and exploited in HP EEsofs ADS and MDS circuitdesignsoftware.Bydiscretizingandsimulatingthesignal envelopesonthedefinedcarrier,theenvelopewaveformhast
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- Efficient analysis of microwave passive structures using 3-D envelope-finite element EVFE envelope
链接地址:https://www.31doc.com/p-3655644.html