*The structure may propagate in 3 modes: coplanar waveguide, coupled slot lines and microstrip. Differential Microstrip Impedance Calculator | Differential Microstrip Impedance Calculator (Using Zo) | Embedded Microstrip Impedance Calculator | Microstrip Width Calculator | Transmission Line Mitred Bend Calculator ; Radar Calculators:Differential Impedance Differential Impedance: the impedance the difference signal sees ( ) ( ) 2 2( ) Z 0 small I V I V diff Z diff one one = = ≈ − Differential impedance decreases as coupling increases +1v -1v I one x I two How will the capacitance matrix elements be affected by spacing? C 12 C 11 C 22 Eric Bogatin 2000 Slide -18. 4, that's why there is a difference in impedance values of microstrip and stripline. The amount of the voltage reflected back is given by the following equation. 3. Where. The impedance Z 0 of a transmission line consisting of a circular signal conductor having a diameter d and centered between parallel ground planes separated by a distance h is given by: Eq. THESE FORMULAS ARE. w (trace width) = d (trace separation) = t (trace thickness) = h (dielectric thickness) =. The initial voltage launched into the transmission line is A . Microstrip Mitred Bend Calculator. Line length Lz = 5 inches Task3. It was found that the microstrip showed more benefit than the CBCPW when comparing a smooth copper to a rough copper surface for insertion loss. Coplanar Waveguide Calculator. Compatible with Flex PCBs and Turnkey PRO service. Increasing W decreases Zo. Impedance (Ω): The desired impedance. where Z 0,surf can be computed as specified in Eq. 3: Normalized characteristic impedance and normalized effective permittivity of a microstrip line as a function of u = w / h. Radio Frequency Engineering Calculator. Relative Dielectric Constant ( εr ): Track Width (S): mm. com To use the Microstrip Differential Impedance Calculator, follow these simple steps: Input the known values into the corresponding fields: Characteristic Impedance (Ω) Height of Dielectric Substrate (m) Width of Microstrip Trace (m) Leave one field blank, as this will be the variable you want to calculate. Ground. The finished layout is shown in Figure 5. Maximum Unambiguous Range Calculator. When driven differentially the impedance is ~100 ohms; and when driven signal-ended (SE), the impedance is ~ 56 ohms. The allegro calculator gives a value of 56. This paper is part 2 in the Ultra-Fine Line Design Guide series. W1: Width of the bottom surface of the trace. 7 Ω lines, using both length and width values for a quarter wave transformer will yield the best results. This section presents formulas for the effective permittivity and characteristic impedance of a microstrip line. 3 Design Formulas for a Stripline. 8 substrates of various thicknesses. The idea here is to determine the spacing required for a given width with the goal of hitting a specific differential impedance value. The differential impedance will be a bit less than 2x the single-ended impedance. Transmission Line Mitred Bend Calculator. The speed of the electromagnetic wave in the free space is 3 x 10 8 meter per second. Edge-Coupled Microstrip. 7. These radio frequency calculators help with unit conversion, attenuator design, antenna design, radars, and various other basic calculators. Spacing and width value pairs that will give a differential impedance of 100 Ohms on Dk = 4. Effective Antenna Aperture Calculator; Maximum Unambiguous Range Calculator; PULSE REPETITION FREQUENCY (PRF) CALCULATOR;Calculate Microstrip impedance for given PCB parameters. 5 Summary; Microstrip is the most popular medium for circuit design at frequencies ranging from several hundred megahertz to tens of gigahertz. Introduction to dispersion diagrams and eigenmode simulator. Calculating the Differential impedance is a two-step process, first Calculate the single ended impedance Zo and then use this value to calculate the differential impedance. Sample coupon — Gerber Data mpcd1345. Voltage Divider Calculator 1 (Fixed) Voltage Divider Calculator 2 (Adjusteable) Capacitors. High-end calculators can rely on top-of-the-line systems to cover any computing speed deficiencies, but general impedance calculators must make a clear design tradeoff. Note that any calculator application (such as the calculators I created in some other blogs) or the Layer Stack Manager in Altium Designer will only return L or L p. This tool helps you create a matching circuit so that optimal power transfer occurs between unmatched loads. Crosstalk Area of the Differential Calculator:Quiz from the book - Signal Integrity for PCB Designer. Ω/mΩ/in. The outer two layers are microstrip signal layers and the inner two layers are power and ground. A web-based tool to calculate the impedance of your PCB traces and vias. Altium Designer incorporates these features into its CAD tools. 1 of the Microstrip Calculator using H2 in place of h, εr,eff can be computed as specified in Eq. Z o is the impedance of an individual trace. coupledmicrostrip = coupledMicrostripLine creates a default coupled microstrip transmission line with a Teflon substrate and default properties for a resonating frequency of 1. 7mil. If JLCPCB's 4-layer PCB is. Trace Width. Note that the "h", for dielectric thickness in this formula is omitted in some other Polar publications. Visit to learn more about our other electrical engineering tools and resources. With PCBWay impedance calculator, you can calculate the approximate impedance of your PCB / high frequency circuit board. If there are changes in the design, change. 5oz. Differential Trace Microstrip Impedance Calculator; Differential Trace Stripline Impedance Calculator; The standard geometries that are supported by these trace impedance calculators are shown in the graphic below. 5 × W, W + 2 × S ≤ 5 × H, dielectric constant >3 for higher accuracy. The impedance Z 0 of a transmission line consisting of a circular signal conductor having a diameter d and centered between parallel ground planes separated by a distance h is given by: Eq. For example the impedance. Differential Stripline Impedance Calculator. Following is the formula for differential impedance for a Microstrip. 0. Differential Impedance of Microstrip. Z 0 Differential impedance (Ω): Calculate. This calculator determines the differential microstrip impedance of a transmission line. 6. One of the features of this type of microstrip is the coupling between lines. Figure 1. Ensuring impedance-controlled routing also requires knowledge of the substrate’s dielectric constant and your required trace width. Notes: 1) Calculation assumes traces are centered vertically. The plots show the magnitude and phase of the input impedance. then the differential impedance will be less sensitive to over-etching or under-etching during pcb fabrication. T T = trace thickness. h = rfckt. I used some online calculator to calculate parameters of trace so it has 50 Ohm impedance. Radar Calculators. This function converts of a set of conventional, 2-port, single-ended S-parameters into a 1-port differential impedance. Comparing these results with end coupled and parallel coupled above in Fig. Differential Impedance Calculator. 37) If H1<1. There are some advantages to. For example, if you wish to input "25000000", just type "25M" instead. At the receiver, the signal is recovered by taking the difference between the signal levels on. Trace Thickness. The characteristic impedance is given by: Eq. 75V C . 0075e-6 meters. This structure supports both an even and an odd mode. Mutual inductance and capacitance exist between the two traces in a differential pair. Dielectric Thickness: mm. There are many free (e. The ground plane helps keep the EMI localized and the trace impedance continuous. • As shown in Figure 1, traces should be 100-Ω(±5%) differential impedance of differential microstrip or differential stripline. I used the differential impedance calculator in the x-section dialog and also the allegro impedance workflow a few times. As seen from the formula when D decreases, while keeping H constant, Zdiff decrease. 8, it is noticeable that results are better for the following parameters. 5oz inner copper, 8 mil trace spacing) and a target differential impedance of 100 ohms, JLC's calculator suggests a trace width of 8. The phase is mostly + 90 ∘ or − 90 ∘, indicating that Zin is mostly reactive. I am reproducing it. To Calculate Input the values of characteristic impedance, trace height, and spacing between traces to obtain precise results. If JLCPCB's 4-layer PCB is. PCB Coplanar Waveguide Calculator RF PCBs can be complex boards that need careful. Calculate the Differential Microstrip Impedance of a transmission line based on the the distance between the strips, height of the substrate, trace thickness and dielectric constant of the substrate. D = trace edge to edge spacing. zodiff: Calculate the characteristic impedance of differential microstrip lines. W. Using a 4 GHz reference antenna, the variations of input impedance and radiation patterns are compared, for (a) changing the feed positions to the non-radiating edge against (b) changing the width of a. 4mil and the dielectric thickness to the first intermediate layer (this is a 4-layer board) is 6. [22] Figure 2 keeps the impedance Z 0 at 50 W while changing the dielectric "r; this requires the ratio w/h to change. The trace width is important as it determines the single-ended and differential impedance, capacitance, and inductance. On the other hand, microstrip will radiate more energy due to its exposure on an exterior layer to air. microstrip = microstripLineCustom (Name=Value) sets properties using one or more name value pair arguments. 66, the trace height is 1. 5 resin). The loss calculation is divided into conductor loss and dielectric loss. 035mm and Er = 4. Since PIe edge connector’s character impedance is 85Ω, the traces between the connector and I should be 85Ω -- the rest is usually set to 100Ω. In other words, if you are designing to hit a differential impedance target. This simple concept provides digital systems. Changed the RO3250 Er to 3. 3. Note: Units do not matter for this calculation as long as they are consistent. Single ended traces impedance control is less important in review perspective. In stripline specifically, the trace width (w), the trace thickness (t), the distance between ground plates (b), and the relative permittivity (better known as DK). Include both the pcb dielectric thickness as well as the wire insulation in the height calculation. These values depend upon the geometry. Notice that the Ground and Power are interchangeable. For microstrip traces, a solid ground plane is needed under the signal traces. 5. The Calculator Calculates the values of the Characteristic Impedance, Capacitance per unit length and propogation speed. Description. The software requires to create a group of signal or create a matching pair and mention the allowed length or time mismatch. This calculator is designed to find the characteristic impedance of an asymmetric stripline - a flat conductor between two ground planes. 2. Also, be aware, 90 ohms is the differential impedance, the characteristic or single ended impedance will be more than half (ie. Calculate the Differential Microstrip Impedance of a transmission line based on the Single Ended Impedance of the transmission line, the distance between the strips and the height of the substrate. Coupled Coplanar TracksImpedance Calculator Home: Layout > Impedance Calculator E dit: Check Layout > Impedance Calculator N avigation T ree: Technology > Impedance Calculator. The advantages of coplanar waveguide are that active devices can be mounted on top of the circuit, like on. We will call the high speed traces the Transmission Line. 4. The JLCPCB Impedance Calculator computes track width values and recommended stack-ups from user-input values of board layer, thickness, copper weight, target impedance, trace spacing (for edge-coupled pairs), and impedance trace to copper gap (coplanar waveguides). These equations are relatively simple compared to other transmission line geometries, comprising only 2 interrelated equations for the microstrip impedance and. Employ our online Microstrip PCB Differential Impedance Calculator to precisely determine the differential impedance of microstrip traces on a Printed Circuit Board. 3 enable the electrical characteristics to be determined given the material properties and the physical dimensions of a microstrip line. Broadside-coupled Asymmetric Stripline. Calculating the Differential impedance is a two-step process, first Calculate the single ended impedance Zo and then use this value to calculate the differential impedance. In design, the physical dimensions must be determined given the desired electrical properties. 8. ϵr ϵ r = substrate dielectric. Dielectric Thickness: mm. t = Trace Thickness. In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. 1< W/H < 3. Embedded Microstrip. single-ended and differential. So I decided to try and verify the calculator - jlcpcb offer an impedance calculator in their quotation system, and for a 6-layer 1. Characteristic impedance of a microstrip line. Zo (diff) is calculated to be 244 ohms, so dividing by two yields a value of 122 ohms for the semi-coplanar structure. 8. Track width (w) = 137 micron. Figure 81 shows the topology. 8. ( 0. Calculate Coplanar impedance for given PCB parameters. The trace widths are 7 mils wide with 8 mil separation. Differential microstrip impedance calculator; Differential stripline impedance calculator; If you want to get more accurate calculations, and you want to account for more advanced challenges like copper roughness, you will need a more advanced calculator. Agilent's LineCalc tool calculates Z odd = 50. The surface finish is neglected. the TLines-Microstrip library. 986 dB with a dimension reduction. Edge coupled microstrip impedances (Z 0,odd, Z 0,even, Z 0,diff and Z. Z 0 now meets your requirements. 3. This document covers the theory, design steps, simulation and verification of various types of power dividers, such as Wilkinson, T-junction, and branch-line. *The structure may propagate in 3 modes: coplanar waveguide, coupled slot lines and microstrip. Increasing H increases Zo. We will also explore how and why to add a multilayer PCB. 96D/H) Zo = Single Ended impedance. Note that Zdiff (differential impedance) is equal to 2 * Zodd, so a Zodd of 45 Ω gives us a Zdiff of 90 Ω. 0; 1 < ε r < 15 ) Select the units for all dimensions: mm mils. These transmission line arrangements are standard trace geometries implemented in PCB design software. Differential Microstrip Impedance Calculator (Using Zo) Embedded Microstrip Impedance Calculator. In both cases, you’ll need to enter your stackup information into the calculator to get accurate results. Even Impedance The impedance measured when testing only one of the. S1: The separation between the two traces of the. Dual Stripline Trace. If you want help fix this. A microstrip is a type of transmission line in which a strip of a conducting material like copper is mounted on a dielectric material and routed to a. Calculates the resistance, inductance and capacitance per unit length of common low-loss transmission line configurations. Coplanar Waveguide With Ground Characteristic Impedance Calculator. 0 2. The embedded microstrip has a similar construction to the microstrip except for the additional dielectric subtrate on top of the conductor. Embedded Microstrip Impedance Calculator. The microstrip calculator determines the width and length of a microstrip line for a given characteristic impedance (Zo) and electrical length or. Modeling approximation can be used to understand the impedance of the edge couple differential stripline transmission line. These formulas are fits to the results of detailed EM simulations. The input impedance, Zin, of the shorted microstrip line is shown in Figure 3. In design, the physical dimensions must be determined given the desired electrical properties. Make sure the correct Layer is selected before changing this option. Microstrip Width Calculator. Frequency f = 500 MHz. T. Calculates the characteristic impedance and per-unit-length parameters. Radar Calculators. Figure - Single Ended impedance calculator. Differential impedance refers to the characteristic impedance between two lines when they are driven differentially (Like USB D+ and D-). Testing with Test Coupons. This is 1. Rs =. 6mm 4 layer PCB, 1oz outer copper, 0. It mentions formula or equations used in this differential Microstrip Impedance Calculator. 8. g. Build a model from experimental data of impedance vs. Use a 4-layer board so you can achieve h ~= 0. Impedance Calculator - Sierra Circuits. This is a required. The differential impedance depends upon the D/H ratio. For microstrip, you can (approximately) cut metal losses in half by doubling the dielectric thickness and keeping the same system impedance. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a calculated impedance according to the IPC-2141 standard. PCB samples, finding that predicted accuracy varies according to target impedance. This tool helps you create a matching circuit so that optimal power transfer occurs between unmatched loads. 3. 588 mm and relative permittivity of 2. Transform Delta to Y: Add Series/ Parallel Resistor: None R in Series with R1 R in Series with R2 R in Series with R3 R in Parallel with Ra R in Parallel with Rb R in Parallel Rc. Calculate Z 0 as normal Microstrip, until you get the desired value, e. Pi-Matching Impedance Network Calculator. I am using Ansfot 3D simulator to model microstrip lines , how to calculate the physical length of microstrip line to model it in. The microstrip PCB differential impedance calculator is also vital in RF and microwave systems, where differential signaling is used for RF and IF signal transmission. The HIGH level is brought up to a logic level (5 V, 3. This calculator determines the impedance of a symmetric differential stripline pair. The JLCPCB Impedance Calculator computes track width values and recommended stack-ups from user-input values of board layer, thickness, copper weight, target impedance, trace spacing (for edge-coupled pairs), and impedance trace to copper gap (coplanar waveguides). 11. In the case where you are routing differential pairs, then the potential between the two pairs will always be opposing (i. mm mils. 2 Loss of CPW lines; 3. The grounded differential coplanar wave guide is the differential version of the grounded coplanar wave guide and is used in high-speed digital systems that require maximum noise immunity. The Calculator Calculates the values of the Characteristic Impedance, Capacitance per unit length and propogation speed. Polar or rectangular grids only allow direct reading of S11. Impedance calculation Delta Impedance, Ra (Ohms) =. An embedded microstrip is a microstrip transmission line or flat conductor separated from the ground place via a dielectric material. e. Calculate Coplanar impedance for given PCB parameters. 427e-9 s/m = 1. Since stripline traces are typically3. Delta Impedance, Rc (Ohms) =. An embedded microstrip is a microstrip transmission line or flat conductor separated from the ground place via a dielectric material. ; Apply the values to the differential calculation, e. trace geometry, and use this to calculate impedance. The grounded differential coplanar wave guide is the differential version of the grounded coplanar wave guide and is used in high-speed digital systems that require maximum noise immunity. 3. Agilent's LineCalc tool calculates Z odd = 50. Grounded Differential Coplanar Wave Guide. – Striplines are embedded between two. 4. $egingroup$ The top link took me to a single microstrip calculator and not a differential one as per your values that you entered. Remember, copper roughness increases the magnitude of the skin effect and creates additional lossy impedance. 1) describes the series connection of short- and open-circuited stubs having characteristic impedances of Z 0 / 2 and half the original electrical length. LineCalc was used to calculate the length and width for a quarter wave transformer. Access Rogers' calculators, literature, technical papers and request samples on your smart phone or tablet through the ROG mobile app. For this calculation, the units of d and h can be ignored as long as they have the same unit. differential impedance : NOTE: numbers are in scientific notation (e. Just as was the case with microstrip impedance calculators, stripline impedance calculators tend to rely on either the IPC-2141 formulas or on Wadell’s equations. But of course, you could also use Z0=50Ohm, and then your 100 Ohm line would be at the 2*Z0 location in the Smith chart. In general, it is double the odd-mode impedance, which is the value we care about for differential signaling, as it is used in high-speed PCB design. microstrip returns a microstrip transmission line object whose properties are set to their default values. Enter your board parameters and get instant results. When Zodd = Zev, the traces are deemed to be uncoupled and there will be no crosstalk (XTalk). There is no closed-form equation like equation (4) for surface or embedded microstrip of any track thickness. 5. You could use thinner traces with these differential microstrips, but you would need to use a smaller spacing. The results are summarized in figure 4. The cloder the two traces, the smaller is the differential impedance. The Dk calculator software can provide outputs as raw Dk data or as averaged output data points. For example, microstrip = microstripLineCustom. 3: Normalized characteristic impedance and normalized effective permittivity of a microstrip line as a function of u = w / h. D = trace edge to edge spacing. 3. RF calculations and RF conversions include metric. Embedded Microstrip Impedance Calculator. This, by definition, gives a target of an odd mode impedance of 45 Ohms and an even mode of 60 Ohms. Part 1 is about how small a neckdown is acceptable. PCB Trace Impedance Calculator. First to calculate the characteristic impedance of the Microstrip line, because the top layer and the bottom layer symmetry, only need to calculate the top layer impedance is good, using polar si6000, the corresponding calculation graph is as follows:. If a. 4. Embedded Microstrip Impedance Calculator. I am trying to design a USB circuit, where the signaling is over a differential pair D+ and D- and these two lines are required by the spec to have 90 ohms of differential impedance. 1 to 3. RF Calculators. Board thickness (h) = 50 micron. Edge coupled differential pair. These are covered in some detail within IPC standard 2141A (see Reference 1), but information on two popular examples is shown here. Following is the formula for differential impedance for a Microstrip. The Smith chart center (1*Z0) is your reference impedance. mm mils. 3 shall be used. In terms of how these calculators work, the impedance of a transmission line in a PCB can be calculated in four ways: Use the R, L, C, G parameters from the Telegrapher’s equations to calculate the impedance of the transmission line. 2. This technique doesn’t work for wide band requirements, but is a simple way to achieve this at a specific. Such a stripline is constructed with two traces referenced to the same reference planes above and below the traces with a dielectric material between them. Hello! I'm trying to calculate the trace width for a differential pair (carrying MIPI CSI-2 signals), using JLC's impedance calculator. H = distance to nearest reference plane. So, I am trying to figure out. I'm designing a custom PCB around the Raspberry Pi RP2040 MCU. In this measurement, a voltage source is used to excite Port 1 and the received signal at. Note: The results are only for approximation and rough estimation, the final values and the. Given a value for impedance, it will (in most cases) calculate. 4 Differential Line and Coplanar Strip; 3. 5 GHz. You will need to know the thickness of the dielectric you will be using as well as the relative permittivity (dielectric constant). The characteristic impedance of the microstrip line changes with an increase in frequency. Their hardware design guideline said the traces between the USB and the termination resistors should have a differential impedance of 90 ohms. Open the PCB layout tool (pcbnew) and go to File > Board Setup. 2 Loss of CPW lines; 3. The range of accepted values is 20 to 90 Ω for single-ended and 50 to 150 Ω for differential signals. There are 3 types of single-ended models:. The characteristic impedance ( Zo) of a single trace, in isolation, is equal to the geometric average ( Zavg) of Zodd and Zev. The range of accepted values is 20 to 90 Ω for single-ended and 50 to 150 Ω for differential signals. 77 mm gave me a differential impedance very close to 90 Ω. Since stripline traces are typicallyStripline Impedance Calculator Embedded Microstrip Impedance Calculator Microstrip Impedance Calculator Dielectric Thickness (mils) C Dual Stripline Impedance Calculator Asymetric Stripline Impedance Calculator Zo Equation: IPC-D-317A (Eq. This has been a research topic for differential serial protocols over the last several years, and standards like USB 4 place specific requirements on broadband signal integrity metrics. H = distance to nearest reference plane. The PCB Impedance Calculator in Altium Designer. NOTE: The formulas used in the program are valid for 0. View All Tools. other parameters of importance, such as the impedance Z 0 and the propagation velocity v g of the microstrip line. The characteristic impedance (Z o) of coplanar waveguide with ground or microstrip lines with signal side ground plane can be calculated using the active calculator or the equations at the bottom of the page. At low frequencies near 0 GHz, the input impedance is inductive since. For this calculation, the units of d and h can be ignored as long as they have the same unit. Given the defaults (1. The driver has an output impedance of 10 ohms. It mentions formula or equations used in this differential Microstrip Impedance Calculator. Tutorial 3: Dispersion Diagram II: Sievenpiper Mushroom. Read more about designing to a differential impedance specification; Read more about the six important transmission. Loss is calculated as a combination of dielectric loss and conductor loss at the analyzed/synthesized length. How to Determine Impedance? Impedance is usually between 25 to 125 ohms in a trace, depending largely on the following factors: The width and thickness of a copper trace;. g. Figure 81 shows the topology. Our RF and microwave calculators and converters will provide the figures you need for your radio frequency engineering needs. Line length Lz = 5 inches TaskDetermine the routing mode, parameters, and impedance calculation. Try TNT or TxLine. However, if the impedance of the transmission line changes for any reason, a part of the electromagnetic wave is reflected back towrds the source. Select the dimension unit of the stripline: mm mils. For example, coupledMicrostripLine (Length. There are different ways to calculate the trace widths for controlled impedance routing: Use one of the many calculators that are available online. 0; 1 < ε r < 15 ) Select the units for all dimensions: mm mils. For your convenience, we have designed an Impedance Calculator to help you calculate the impedance and the trace width you require. With specific circuit. The source for formulas used in this calculator (except where otherwise noted) is the Design Guide for Electronic Packaging Utilizing High-Speed Techniques (4th Working Draft, IPC-2251, February 2001. 5 x 10 8. Grounded CPW transmission line impedance calculator. 6: Microstrip Design Formulas. Try This New Tool. Embedded Microstrip Impedance Calculator. The rules shown below are a rough approximation, and you should always check the approximation using an impedance calculator or field solver. 3. Adjust the distance "s". 1 High Impedance; 4. Distance between tracks (s) = 254 micron. h = Dielectric Thickness. DP, DM Differential trace impedance = [DP(45ohm) + DM(45ohm)] = 90 ohm, and do not jump the DP DM signals that cause impedance miss match. The required inputs are the Dk value for the dielectric constant of the PCB substrate, and the. Figure 1 illustrates the affect of soldermask coating on microstrip impedance. 003” flex cores for a stripline configuration. Microstrip traces are a practical and straightforward method for establishing transmission lines on a PCB. This calculator can calculate the impedance and propagation delay of any microstrip by taking its respective height, width, thickness & dielectric constant. Click the button corresponding to the characteristic impedance to calculate its value. 8. This calculator assumes. In some cases, users require a custom impedance value. Separation between Planes. Overview. 98mil. Reference: R. Figure 9 shows the simulated result of the fifth-order hairpin bandpass filter. Cohn, Seymour B. p = (Zi - Zo) / (Zi + Zo) Let us consider the case Zi = Zo. Tpd: propagation delay. 3. The answer lies in the spacing between the traces in the pair. 1. 0 (FR-4), it turns out that when W/H is 2/1, the resulting impedance will be close to 50. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. Width (w) Trace Thickness (t) Dielectric Thickness (h) Relative. Altium Designer’s differential line impedance calculator will set up your impedance-controlled differential pair routing widths for you. Twisted pairs are used with balanced signals.