This is an animation from a simulation of a coplanar waveguide cpw done in ansys high frequency structural solver hfss. Using hfss for simulation and adk 7 for postprocessing. Wu microstriplines microstrip structure inhomogeneous structure. Techniques for analyzing antenna lattice structures. However, in practical circuits, the differential signal pairs may accompany unwanted common. Currents about the symmetry line are equal in value and opposite in sign. L wi for i 1, 2 are the inductances per unit length of the appropriate micriostrips, having widths w 1 and w 2, respectively. Aggressor separation microstrip routing requires a separation of 6h and 7h to properly manage the crosstalk coupling to less than 1% for next and fext, respectively. Apr 09, 2018 this video compares the sparameter results for the differential pairs after solving the printed circuit board in ansys siwave with and without hfss regions. The end goal of this example is to run a transient circuit analysis or lna simulation. Eecs 117a demonstration 4 hfss simulation of a transmission line. Hfss results create report im or re z11 or 1y11 and find at which frequency the line could be used as a resonator. Training and tutorial material are available for both a broad range of ansys products and users experience. In the lumped element model we have a pair of differential equations to describe the voltage and current along the line under the limiting argument which converts the circuit to distributed element form, we now have a pair of partial differential equations, which when.
Click on the image to open in a new window the left and right drive gears have teeth on their sides. The acronym stands for high frequency structure simulator. Again, the exact number may be less, depending on the speed of the interface. Differential via two singleended vias used for differential signaling the minimum via pitch size is determined by the manufacturing specification the coupling overlap of e,h field lines changes the differential impedance, zdiff20. A novel method to reduce differential crosstalk in a high. Emiemc and coexistence simulation methodology xavier lecoq. But, depending on the application, the differential pairs will most likely need to be relative to the length of other differential pairs in the same group. Much of the material of chapters 26 and 8 has been adapted from the widely. Ansoft high frequency structure simulator v10 users guide 5. The larger the coupling tight coupling is, the lower the differential. Due to the fields within two guidedwave media, the microstripdoes not support a pure tem wave. Then essential simulation parameters include 3 figure 6. Transceiver link design guidelines for highgbps data. Consider two differential pairs routed on the same signal layer as shown in figure 9 with a height h from the reference plane.
Compute the reflection and transmission coefficients of a frequency selection surface. It shows the electric and magnetic vector fields at 10ghz as well as. New editions of this manual will incorporate all material updated since the previous edition. An903a comparison of differential termination techniques. Often, this feature is used to calculate a step response or timedomain reflectometry tdr plot of the. How to model vias of highspeed differential pairs with. Figure 3 compares an optical module driver in both singleendeda and differential b modes. Sep 24, 2015 a differential amplifier has two inputs, one inverting and one noninverting.
As a concrete example, we look into the design of an inter layer connection represented by a differential pair of vias built within a 18 layer pcb stackup. Business business, international computers and office automation circuit printing design and construction printed circuit boards. An ideal differential ramped step source with a magnitude of 1 v and a rise time t r of 50 ps is now driving the dsdml. Problem description getting started create the 3d model analysis setup plot sparameters vs. Numerical example of 15 signal viapairs and 20 ground shielding vias in 6 layer board.
Hfss is one of several commercial tools used for antenna design, and the design of complex radio frequency electronic circuit elements including filters, transmission lines, and packaging. I have done the impedance calculations to figure out the. When the longitudinal components of the fields for the dominant mode of a microstrip. Differential amplifier basics, usage and differences. It consists of a square patch, a via, and a square block of substrate as shown in fig. Magnetic nearfield map of a digital interface with 4 differential pairs 3 data lanes and 1 clock figure 7. I have a question about the differential pair definition in hfss driven terminal simulation. Ansys hfss tutorial simulate and analyze an example of trace and via. Often, this feature is used to calculate a step response or timedomain reflectometry tdr plot of the structure being simulated. The differential pair in hfss driven terminal simulation. Included in these notes are links to short tutorial videos posted on youtube. The objective is to provide a very thorough introduction to hfss as applied to antenna design, which may be followed stepbystep in.
Tools options hfss options general tab check use wizards for data input when creating new boundaries check duplicate boundariesmesh operations with geometry click ok. Aggressor separation microstrip routing requires a separation of 6h and 7h to properly manage the crosstalk coupling to. Single ended and differential operation basic differential. Broadsidecoupled routes one trace exactly over the other on 2 separate layers as dual stripline. Getting started with hfss v9 for antenna design october, 2003 this getting started training material is intended for new users of hfss. It was originally developed by professor zoltan cendes. Position and dimensions enter the position and the dimensions of the created cylinder as shown in the gure below. Window functions and timedomain plotting in hfss and. I am trying to get the results of the paper attached. Base specification and design guide for serdes highspeed electrical signaling document version. A differential amplifier has two inputs, one inverting and one noninverting. Differential pair use early applications for differential pairs mecl i 1962 mecl ii 1966 mecl iii 1968 mecl 10k 1979 mecl 10kh 1981 ansitiaeia6441995 is the generic physical layer standard for lvds.
Ansys hfss tutorial simulate and analyze an example of trace and via tianjian lu 02014 tianjian lu ece 546. Introduction antenna definitions w what is an antenna. Hfss is a commercial finite element method solver for electromagnetic structures from ansys. The objective is to provide a very thorough introduction to hfss as applied to antenna design, which may be followed stepbystep in hfss with the investment of only a few hours of time. Within the wave port dialog, the differential pairs tab controls the creation. Layout driven assembly in ansys electronics desktop. Next, the unitcell of the sievenpiper mushroom structure has to be drawn in hfss. Design a differential via pair and investigate the signal. Let ports 1, 2, 5, 6 denote the first pair and ports 3, 4, 7, 8 denote the second pair. Considerations for pcb layout and impedance matching design. Najmabadi, ece102, fall 2012 1933 differential mode circuit.
Differential amplifiers single ended and differential operation basic differential pair commonmode response differential pair with mos loads hassan aboushady university of paris vi b. But in driven terminal the sheet is defined as port and we just need to. In hfss, you can directly obtain the modal responses and characteristics of a multiconductor. In the lumped element model we have a pair of differential equations to describe the voltage and current along the line under the limiting argument which converts the circuit to distributed element form, we now have a pair of partial differential equations, which when solved yield a solution that is a 1d traveling wave 23.
Pdf how to model differential pairs on different layers with tline models. However, it may not be clear when transmission line techniques are appropriate. Hybrid simulation of a reflector antenna lecture 9. However, the simulation results show that the differential impedance is 116. Design a differential via pair and investigate the. This slide refer the paper from ansofts an, differential pair analysis by j. Can i make differential excitation direct in cst or hfss. They are attached directly to the end of the left and right output. Much has been written about terminating pcb traces in their characteristic impedance, to avoid signal reflections. Search the hundreds of courses available and improve your.
Considerations for pcb layout and impedance matching. Signal integrity analysis of highspeed interconnects. Hfss and siwave allow for timedomain plotting of sparameters. One hfss 3d model of a connector, one hfss 3d layout project of a package design with two differential pairs of nets, and one hfss 3d layout project of a section of a board with two. Emiemc and coexistence simulation methodology xavier. Hfss is an interactive simulation system whose basic mesh element is a. It is essential for the design of high frequency and highspeed component design 4. Ansys high frequency structure simulator hfss tutorial. Hfss ansys hfss is a 3d electromagnetic em simulation software for designing and simulating highfrequency electronic products such as antennas, antenna arrays, rf or microwave components, highspeed interconnects, filters, connectors, ic packages and printed circuit boards. Although the dual backtoback vtcts do not introduce a length. Can i make differential excitation direct in cst or hfss or.
Differentials open, locked, limited slip, edl, quattro. The part of the left is the differential part on right is a viscous coupling anyway, ill explain and you can look at the diagram. Inside the microchip or pair of discrete transistors, the positive and negative signals are added and the resultant becomes the single output. Differential signals transmission ideally maintains good signal integrity and exhibits low electromagnetic emission or electromagnetic interference. Mos differentialpair basic configuration two matched mos transistors common current bias differential signls applied to v g1 and v g2 equal amplitude but opposite sign differential outputs are produced at v d1 and v d2 note in differential configuration, v gs is fixed for both q 1 and q 2 i d1 i d2 i 2 i 2 k n 2 v gs. This video compares the sparameter results for the differential pairs after solving the printed circuit board in ansys siwave with and without hfss regions. Most of the available toolbars are displayed in this illustration of the ansoft hfss initial screen, but your ansoft hfss window probably will not be arranged this way.
Signal transmission analysis of differential pairs using semicircleshaped via structure r a b fig. Hfss high frequency structure simulator hfss is an industrystandard simulation tool for 3d fullwave electromagnetic field simulation. An903a comparison of differential termination techniques abstract the purpose of this application report is to remove some of the confusion that may surround signal termination. Ee105 fall 2015 microelectronic devices and circuits. Find the quality factor of the resonator by sweeping the magnitude of impedance of a short line and observing the 3db bandwidth. Ansoft hfss online help provides assistance while you are working. This discussion will focus attention upon signal termination only as it applies to differential data transmission over twisted pair cable. Aug 07, 2017 this is an animation from a simulation of a coplanar waveguide cpw done in ansys high frequency structural solver hfss. To get help about a specific, active dialog box, click the help button.
Window functions and timedomain plotting in hfss and siwave. How to use hfss to simulate the coupled striplines or make even. Razavi, design of analog cmos integrated circuits, mcgrawhill, 2001. It was approved in november of 1995, and first published in march of 1996. A simple twinrod model for a differential via transition, consisting of a uniform differential pair, can be used to describe a differential via using simple coupled transmission lines as illustrated in figure 3. Differentials open, locked, limited slip, edl, quattro the.
Preface these are notes for the lecture course \di erential geometry ii held by the second author at eth zuric h in the spring semester of 2018. Department of electrical engineering national taiwan university prof. Differential equations department of mathematics, hkust. This book is an emphasis on engineering practice hfss electromagnetic simulation design tutorials. It is essential for the design of high frequency and highspeed component design. I am wondering is the differential terminal port impedance equal to the odd impedance and the common terminal port impedance equal to the even mode impedance in the couple line. Signal transmission analysis of differential pairs using. Since each trace is more tightly coupled to its adjacent reference plane than the opposite reference plane, any noise on the planes will not be common to both traces and thus, will not be cancelled at. We can model differential vias with hfss and combine the model with siwave transmission line models to achieve a tradeoff between accuracy and simulation speed. May 12, 2010 classified document the information in this document is ibmintel confidential and is protected by a confidential disclosure agreement when disclosed to other individuals of other corporations or entities. Investigations have been led to define the appropriate cutout clearance rules. Base specification and design guide for serdes highspeed. First we must configure hfss to use its eigenmode solver.
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