2. 1 to 3. VSWR, Return Loss and Reflection Coefficient. Visit to learn more about our other electrical engineering tools and resources. 3. They consist of a conductor fabricated on the dielectric substrate of permittivity ‘𝜀r’ with a grounded plane. 0 2. Useful converters and calculators. 3: Normalized characteristic impedance and normalized effective permittivity of a microstrip line as a function of u = w / h. The plots show the magnitude and phase of the input impedance. (2) When the line width (w) of the characteristic impedance (Zo) is calculated. Since the antennas showed low return losses compared to. 4. This calculator is designed to find the characteristic impedance of an asymmetric stripline - a flat conductor between two ground planes. (2) When the line width (w) of the characteristic impedance (Zo) is calculated. Users can download and run the easy-to-use executable file on any Windows-compatible personal computer. 71. 3): fHigher-Microstrip = c/(4h εr − 1− −−−−√) = 10. example. Differential Microstrip Impedance Formula or Equation. Click here to see the user guide of our. Getting the Most Accurate Impedance Calculations. This is a hobby project and the. Modeling. g. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. • Plotting 𝐸⃗ fields for magnitude and vector, in both linear and dB scale. Coplanar Waveguide Calculator. There are four different types of impedance used. 4. New Online Microwave Impedance Calculator. This calculator computes the trace width of a stripline if the maximum current, trace thickness, temperature rise, ambient temperature and length are given. With hundreds of coaxial RF cables in-stock and ready to ship worldwide immediately, our coax capacitance calculator lets you calculate the impedance of a coax by allowing you to enter the outer diameter dielectric width and inner conductor diameter. Don’t forget to check out our other. Phone: +44 (0)1425 489 111 / +49 (0) 8104 628 0. One challenge in designing PCB interconnects is maintaining system impedance while reducing crosstalk, which requires reducing trace inductance. They are useful at design time and for training purposes, both of which stimulated. Resistance Tables. The default units for all given values, except the subtrate. To use these to design for a target impedance, simply cycle through various geometric values for the trace width until the calculator returns the target impedance. All transmission lines are 1 ounce thick (1. Useful converters and calculators. Click the button corresponding to the. Stripline. Sorted by: 1. Where a Microstrip Line Calculator Fails. This limits the use of ƛ/4 microstrip stepped-impedance resonators in low-frequency filter applications. High-speed designs carry a requirement for controlled impedance, crosstalk control, and the need for interplane capacitance. EEWeb offers a free online twisted pair impedance (transmission line) calculator. T-Match Topology. INPUT DATA. There are many calculators available online, as well as built into your PCB design software. View All Tools. Just enter the given values for trace thickness. Don’t forget to check out our other. The Differential microstrip impedance calculator is used to compute the differential (Zd) and single-ended impedance (Zo) of an edge-coupled microstrip line just by entering the width, separation and thickness of the trace along with the dielectric thickness and constant of the coupled line. To calculate this, you need some values. The characteristic impedance of the microstrip line changes with an increase in frequency. Understanding coax can be helpful when working with it. 3 Filling Factor; Microstrip has conductors embedded in two dielectric mediums and cannot support a pure TEM mode. EEWeb - Electrical Engineering News and Resources. Introducing the newest version of the Microwave Impedance Calculator from Rogers’ Advanced Connectivity Solutions. Differential microstrip impedance calculator is an online electronic tool to measure the opposition to alternating current. dBm to Watt converter Stripline Impedance calculator Microstrip line impedance Antenna G/T Noise temp. Dimensional units: mm mils Zo (single ended impedance, Ohms) = d (trace separation) = h (dielectric thickness) = Zd (Impedance, Ohms) =Calculate Microstrip impedance for given PCB parameters. Each Port is matched to the characteristic impedance Z 0 of the single, isolated microstrip transmission line. Viewed 205 times 1 $egingroup$ I am attempting to determine the trace width needed for routing a differential signal of 100 Ω on a PCB I am designing. If the dielectric constant of the material is not known, you can choose to put in the velocity of. In the next page we will see what factor effect the differential impedance and how to calculate it. Design a transmission line segment that matches 300 Ω to 50 Ω at 10 GHz using a quarter-wave match. Read the latest Microstrip Crosstalk Calculator forum discussions in the electronics and electrical engineering communities. 1t for W/h ≤ 1 and Wr = W + 1. Microstrip line. Terminate the transmission line in its characteristic impedance when the one-way propagation delay of the PCB track is equal to or greater than one-half the applied signal rise/fall time (whichever edge is faster). 55 GHz for VSWR < 2, which corresponds to a fractional. ferent methods for calculating the input impedance of microstrip antenna. 7E-6 [Ω · cm] L is the trace length [cm] T is the trace thickness [cm] W is the trace width. The Smith Chart achieves this by superimposing a grid on S11 that maps load impedance. t is the Thickness of track (1 oz/ft2 = 0. If the ratio is about 0. The CST Cable Studio Impedance Calculator can be started from Cables > Impedance Calculator. microstrip = microstripLine (Name=Value) sets properties using one or more name value pair arguments. Microstrip lines have three parameters that we can change to achieve 50 ohm impedance: Due to design constraints, there is only one parameter (track width,) left to achieve 50 ohm. The calculator is set up to handle an asymmetric arrangement, where traces are not centrally located in the PCB layer stack. Make sure the correct Layer is selected before changing this option. L-Match Topology. I got the following question regarding the impedance of a grounded coplanar waveguide(gcw) and microstrip as shown in the image attached: If I increase the spacing w in the gcw to large values I am expecting getting a similar impedance results for the microstrip if the other parameters remain the same since both geometries equalise. 76mm Rogers4350B substrate at a certain frequency and with 35 micron copper thickness, line width becomes 0. The resulting model is said to be a good model if it has the following characteristics [1]: •It can be used to calculate all impedance and radiation characteristics of the antenna under discussion. 6 ohms. Such a microstrip is constructed with two traces referenced to the same reference plane with a dielectric material between them. Relative Permittivity (input1) : Height of substrate (input2) : Width of line (input3) : Microstrip Line Impedance in Ohms (Output1): Effective Permittivity (Output2): EXAMPLE: Relative permittivity = 10. 8. This calculator finds both odd and even transmission line impedance. Input the parameter of the circuit board and center frequency. 2. Introduction The edge couple differential microstrip transmission line is a common technique for routing differential traces. Lots of calculators can do embedded microstrips, so you can see for yourself. Also, take into consideration the board's dielectric thickness and. Wheeler’s equations for microstrip trace impedance. The PCB internal/external trace resistance shall be calculated according to the following formula: R = (ρ * L / (T * W)) * (1 + α * (TAMB – 25 °C)) Where: R is the trace resistance [Ω] ρ is the resistivity parameter, whose value for copper is 1. 1 W/H 3. Microstrip impedance calculator Mixer spur calculator mmWave Link Budget calculator Noise Figure/Temp converter Optimal Mitre calculator Path loss calculator. There are some advantages to using a microstrip transmission line over other alternatives. As seen here:Figure 3. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion, copper roughness, phase shift, etc. ; Apply the values to the differential calculation, e. Hallmark Circuits, Inc. What is Microstrip Impedance? See full list on allaboutcircuits. 6. To help you run through the above integral, you can download a microstrip trace taper calculator worksheet for use in Excel. Some calculators opt for Wadell's results, yet they simply state they are "based on Wheeler’s method" without providing references. [z0,eff_ep] = getZ0 (txline) returns the characteristic impedance and effective epsilon without dispersion for a microstrip or coplanar waveguide (CPW) transmission line. Microstrip Impedance Calculator Provide values for three of the four parameters H, T, W, Z 0 and the relative permittivity of the dielectric. 2H, the formula for the non-embedded microstrip should be usedThese calculators use a solution for the trace width in terms of impedance, or they use an iterative numerical technique to calculate the trace width from impedance. A simple microstrip is located on the top of the board, while an embedded microstrip is located inside the board substrate as illustrated below. These properties can be useful for making fine adjustments to a microstrip design. *The structure may propagate in 3 modes: coplanar waveguide, coupled slot lines and microstrip. example. There are a number of pcb transmission line typologies. Controlled differential impedance starts with characteristic impedance. Note that if the wire is insulated, then the results of this calculator will just be an estimate. By determining its trace resistance, the contribution of a microstrip to the overall circuit resistance can be evaluated. Using the formula above, we can calculate the characteristic impedance of the microstrip transmission line as follows: Zo = 87 * ln(5. 1< w/h < 3. If, in addition to a differential impedance (Z Diff), you also need a defined Z 0, proceed as follows:. Calculation tip for defined Z 0 as well as Z Diff. I can't quite get it when microstrip starts to behave more like a coplanar waveguide. Once you have the reflection coefficient, you can use it to calculate the S-parameters by comparing with your feedline impedance. This will also provide the time delay the cable provides for a signal and also the capacitance and inductance per. Enter the Height, Width and Permittivity to get the Impedance of the Microstrip Note : The unit of the height and width entered must be the same. 48 e-0. The edge couple differential microstrip transmission line is a common technique for routing differential traces. 29 mm width traces to obtain 100 Ohms ZDiff while using 0. If the ratio (L/W) is close to unity, the radiation pattern will be symmetric but may not provide a resonable input impedance. 15 mm spacing. The microstrip patch antenna calculator determines the length (L) and width (W) of a rectangular microstrip patch antenna for a given resonant frequency or vice versa. microstrip line are assumed to be quasi-TEM, and dispersion along the microstrip line is taken into account using the empirical formulas given in Appendix C. Use the following equation to calculate the impedance of a microstrip trace layout. 6 Ω. 4 GHz, microstrip line feed. The range of dielectric constant (Er) over which the results are valid is 2 to 15. The Calculator has the following tools: Regulators. 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. The stripline impedance calculator provided below is useful for gaining an initial estimate of trace impedance for striplines. 0. Then Rock'n'Roll. icrostrip line: H. So two estimates have been calculated for the frequency at which the first higher-order. This calculator uses JavaScript and will function in most modern browsers. The impedance calculator determines the signal properties and clearances (first image), use that clearance. Coplanar Waveguide With Ground Characteristic Impedance Calculator. Transcalc. ( 0. 8. 6 , Frequency(GHz) = 10 OUTPUTS: Effective dielectric constant = 2. RF calculations and RF conversions include metric. This 26 mil clearance between copper pour and the 13 mil trace is sufficient to ensure 50 Ohm impedance. Please see Disclaimer below. 7. Figure 5. 5mm, T=0. Input parameters. could someone point me towards reliable and proven method to calculate impedances for edge coupled differential microstrip?From here, we can see that there are specific stack-ups where a CPW and a microstrip/stripline will have 50 Ohm impedance and the same trace width, even though the ground clearance is quite close clearance to the trace in the CPW. Usually Microstrip separated from the ground by using dielectric substrate. Cadence’s suite of PCB design and analysis tools can assist you in designing microwave and RF circuits. a) The effective relative permittivity of the substrate. Getting the Most Accurate Impedance Calculations. For small-signal RF circuits, the power delivered to the load is maximized by conjugate-matching it to the source with a. ELECTROMAGNETIC COMPATIBILITY (EMC) CALCULATORS – Electromagnetic Compatibility Laboratory, Missouri University of Science & Technology VERY VERY VERY…EXTENSIVE. Microstrip Impedance. Assuming that there is no loss in the transmission process, the characteristic impedance of the antenna can be expressed by the distributed capacitance C per unit length and the phase velocity Vp:Overview. Edge-Coupled Microstrip. The characteristic impedance (Z o) of a microstrip transmission line can be calculated using the active calculator or the equations at the bottom of the page. This calculator finds both odd and even transmission line impedance, including four different types of impedance used in characterizing differential trace impedances, for microwave antennas, couplers and filters applications. This calculator requires symmetry in the trace widths and location between plane layers. Introducing the newest version of the Microwave Impedance Calculator from Rogers’ Advanced Connectivity Solutions. Microstrip Patch Antenna Calculator Formula. The substrate parameters. 1 Microstrip Line in the Quasi-TEM Approximation; 4. Using this formula, you can calculate the characteristic impedance of a. First, let’s use the “analyze” approach. The T match circuit gets its name because the circuit topology looks like the letter “T”. RF Calculators. The characteristic impedance is an important parameter determining the power handling capacity of a waveguide, both average and peak powers. If you need to find and use an efficient and accurate microstrip impedance calculator that provides lossless impedance values, you can use our free tool below. This calculator is designed to calculate the characteristic impedance of a broadside couple stripline (see diagram below). Rho: Conductor resistivity relative to copper. For microstrip, you can (approximately) cut metal losses in half by doubling the dielectric thickness and keeping the same system impedance. All calculators are approximations for general purpose use only and are not to be used for high degree of accuracy purposes. The edge couple differential symmetric stripline transmission line is a common technique for routing differential traces. Microstrip Calculator computes a microstrip's Effective Dielectric Constant and Characteristic Impedance. The microstrip patch antenna calculator determines the length (L) and width (W) of a rectangular microstrip patch antenna for a given resonant frequency or vice versa. For example, going from 10 mil to 20 mil alumina, or two-mil to four-mil GaAs. 5. Microstrips (Source: Max Maxfield) In order to fine-tune the transmission line properties of the microstrip, we need to calculate the impedance of the trace. The microstrip. With our handy calculator, you can choose from 50 Ohm, 75 Ohm, 93 Ohm and 95 Ohm coaxial cables. However we expect that Equation 7. *Accurate for arbitrary values of Er and w/h ratios. 6 ohms. As with other microstrip devices, the conductor and the ground plane are separated by a dielectric. 74 Microstrip Antenna Design Handbook or more of the features listed above. Pi-Matching Impedance Network Calculator. Also, take into consideration the board's dielectric thickness and. 4: Normalized even-mode and odd-mode effective. Clemson Vehicular Electronics Laboratory: Transmission Line Impedance Calculator. To use this calculator, enter the values for the wire diameter and substrate. 4. 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. This calculator provides accurate microstrip transmission line analysis and synthesis. A microstrip patch antenna is one of the most popular microwave antennas. If necessary, push the CLEAR button. Impedance calculation. Backwards crosstalk creates a pulse width that is twice that of the propagation time of the pulse traveling the coupling distance. When cascaded with high impedance quarter-wavelength transmission lines, the radial stub can provide an effective decoupling network for microwave. This allows you to double check the calculator and make sure that it selected appropriate values, by making sure the impedance correctly matches the input impedance. Microstrip Transmission Line Calculator Using IPC-2141 Equation. For example, if u = 1 and ε r = 10, then from the figure, Z 0 ε e = 126 Ω and ε e / ε r = 0. Characteristic impedance calculator for a 4-layer board. Microstrip Impedance Calculator. Matlab/Freemat file 1. 19. November 21, 2023 Stefano Lovati. Picking from the CST Cable Studio Segments Navigation Tree. Tuning for your traces to the desired impedance value occurs by adjusting trace width and distance from the reference plane. Microstrips (Source: Max Maxfield) In order to fine-tune the transmission line properties of the microstrip, we need to calculate the impedance of the trace. Just enter the given values for trace thickness, substrate heights, trace width, and substrate dielectric. W/H. H (Dielectric thickness) : Embedded microstrips are commonly crafted using printed circuit boards, although other materials can be used. Cross-hatched copper plane in a flex stack-up for controlled impedance. Single-stub matching is a very common method for impedance matching using microstrip lines at frequences in the UHF band (300-3000 MHz) and above. to NFThe coaxial cable, along with the balanced two-wire, is the most common type of transmission line used in RF communications. Analysis for a desired circuit type and material. 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. This calculator is designed to determine the magnitude of the crosstalk on a stripline if its dimensions and source voltage is provided. Ideally clk, mosi and miso tracks should be the same length, kept. A helpful tool for calculating the impedance of a wire microstrip. These two adjustments lead to: Equation DGB2: This equation is the same as, and reduces to, IPC’s Equation 5. This study aims to optimize rectangular Microstrip Patch Antennas (MPAs) in terms of bandwidth, return loss, input impedance, voltage standing wave ratio (VSWR), impedance matching, and resonant frequency by means of a radiating element that is sliced into eight circular slots. This section of the site offers RF engineers quick access to popular calculators and design aids. The calculator allows you to calculate the parameters of a coplanar stripline waveguide, with or without a ground on the PCB bottom side. In both cases, you’ll need to enter your stackup information into the calculator to get accurate results. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. 1 er 15 Note that 1. Both formulas of the dielectric, as well as the total losses, agree. 0; 1 < ε r < 15 ) Select the units for all dimensions: mm mils. The high-impedance lines act as series inductors and the low-impedance lines act as shunt. 5 resin). Calculates the differential impedance of a microstrip pair. This calculator finds both odd and even transmission line impedance. The inductance of a PCB trace determines the strength of any crosstalk it will receive. The plots show the magnitude and phase of the input impedance. By adding the formulas of the dielectric and copper, a similarly simple formula of total attenuation is obtained. An example of a wire microstrip might most often be found in prototypes or reworked boards where a wire is used over the top of pcb or copper clad material. A. Z 0 now meets your requirements. 1< W/H < 3. Relative Permittivity (input1) : Height of substrate (input2) : Width of line. Use an online differential microstrip impedance calculator; Use an online differential stripline impedance calculator The lateral dimensions, however, are well controlled being photolithographically defined and then etched. Broadside Trace Inductance Calculator. 7. 32 and the equation shown in 5. Schematic representation of a PCB patch antenna: The calculator is based on simplified formulas for calculating microstrip transmission lines and is intended for preliminary calculation only. So, the dielectric at my 5-6GHz frequency range is 3. Characteristic Impedance of the System (Z0) Ohms. 3: Normalized characteristic impedance and normalized effective permittivity of a microstrip line as a function of u = w / h. 4. Microstrip Calculator computes a microstrip's height/width ratio, impedance and relative dielectric constant for a microstrip transmission line. 41)] * ln. In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. 293, 50% of the copper removal can be achieved. Procedure: • We know the standard characteristics impedance of microstrip line to be of 50Ω. This tool is designed to calculate the resistance of a microstrip trace with a copper conductor. This tool will also compute the resistance of the stripline, the voltage drop on it, and the resulting power dissipation. The IPC Formulas and Wadell’s Method. 1 (a). A microstrip is created by etching a trace on a printed circuit board and is mostly used in microwave applications. For more information see About. The reflection coefficients at each boundary in Figure 7. eu. 5. The embedded microstrip impedance formula is an approximation and the results are highly sensitive to the values of the variables. Following equation or formula is used for Microstrip Mitred Bend Calculator. 2023-04-04 09:19. The calculator allows you to make an approximate calculation of the characteristic impedance of a microstrip transmission line, provided that the line operates at a frequency below the critical one. 5. Coupled Microstrip Analysis/Synthesis Calculator. Geometric Parameter Definitions: Saturn PCB - Toolkit for Impedance Calculation. These are considered to be standardized impedance values with cables readily available. The input impedance, Zin, of the shorted microstrip line is shown in Figure 3. 635 mm, W = 0. *Accurate for arbitrary values of Er and w/h ratios. The. This tool helps you create a matching circuit so that optimal power transfer occurs between unmatched loads. e. Resonant Frequency Calculator. 0. The calculators on this site are more suitable for calculating antennas at frequencies higher than VHF. Polar or rectangular grids only allow direct reading of S11. For example, a 2 inch microstrip line over an Er = 4. This tool is designed to calculate the inductance introduced by an edge-coupled trace. 5 GHz. (1) When the characteristic impedance (Zo) of the line width (w) is calculated. Differential surface microstrip with ground calculations: ( This calculator gave a different result, don't know why )Overview. 02 m Slotline Equation. Dielectric Thickness: mm. A simple microstrip is located on the top of the board, while an embedded microstrip is located inside the board substrate as illustrated below. A two part calculator which gives ideal and preferred value resistors, showing most formulas used and a link to the others. It also determines the wavelength and the length adjustment. Impedance (Ω): The desired impedance. I would like to know how to compute the impedance at the edge of a microstrip patch in CST. Microstrip Impedance Calculator. These calculators will return an impedance value for pairs of trace width, substrate thickness, and copper weight values. It is a useful tool in the design and analysis of microwave circuits, particularly in the fields of communication, radar, and satellite systems. Calculates with the characteristic impedance of the system and ratio of the power at the output to get the impedance of the various transmission lines that make up the Wilkinson Power Divider. Provide values for the four parameters H 1, H, T, W, and the relative permittivity of the dielectric. For typical PCB parameters (ε r = 4, H 1 = 61. ±1% in h, ±2% in ±1% in C. Coax Impedance (Transmission Line) Calculator. When I google “impedance calculators pcb” this website is the first hit. Microstrip Mitred Bend Formula or Equation. This microstrip impedance. Calculates the width of a Microstrip Transmission Line. Traces in printed circuit boards can often form broadside or edge pairs and may introduce unwanted inductance. PCB Impedance and Capacitance Calculator: Asymmetric Stripline. Microstrip Impedance Calculator Note: valid for (w/h) from 0. A coupled line RF filter was designed and working prototypes of the design performed well. By inputting the known values and leaving one variable blank, you can quickly calculate the missing parameter. microstrip = microstripLine creates a default microstrip transmission line using a Teflon substrate. Dual Stripline Trace. Where: Z 0 is the characteristic impedance of the microstrip; ε r is the relative permittivity (dielectric constant) of the substrate material; h is the height of the microstrip above the. ( 0. Our free impedance calculator for coplanar strips can help you with your design features to ensure your PCB is a working as you intend. 5, determine. The complex propagation constant for this line is given by the equation: γ = ( α + j β) where ɑ and β are the attenuation and phase constants. Most RF Coaxial Cables have an impedance of 50 ohms or 75 ohms. To use this calculator, simply input your microstrip geometry and Dk value, and the tool will return the differential impedance value for a pair of microstrip traces. 1 High Impedance; 4. Here lies the challenge: impedance calculators must balance speed and accuracy. Microstrip impedance shall be calculated according to above Eq. Broadside coupled traces are on adjacent planes and the return is identical to the trace in width and length. For example, if you wish to input "25000000", just type "25M" instead. When in doubt, use 1 for copper, . 0; 1 < ε r < 15). 06228 [dB] keven = 3. This is the only way to calculate the total impedance of a circuit in parallel that includes both resistance and reactance. Dual Stripline. If you're trying to get your own pcb design project , you should use this tool. The frequency of the signal through the microstrip line. 60. This assumes ~0 trace thickness. The substrate parameters (ε r and h) are required. Input Zo, and click on [ Synthesis ] button. Microstrip Width Formula or Equation. PI Network Impedance Matching. Also, any two models that agree with the data to better than. Use this user-friendly online calculator to calculate the impedance, capacitance, propagation delay, and inductance of a Microstrip Line on a Printed Circuit Board (PCB). Characteristic Impedance and Calculation Formula of Microstrip Antenna . One of the features of this type of microstrip is the coupling between lines. Differential Impedance Ω. Impedance Calculator Talk to a Sierra Circuits. 109-115, November 1989. The calculator then uses a formula to calculate the width and spacing of the trace or transmission line required to achieve the desired characteristic impedance. Tiny Origami-Based Flying Robots Enable New Sensor Applications. Provide values for the four parameters H 1, H, T, W, and the relative permittivity of the dielectric. Matlab/Freemat file 1. When I google “impedance calculators pcb” this website is the first hit. There are four different types of impedance used in characterizing differential trace impedances. Line Thickness (T) in mils. 32 and 5. 6 Ω and ε e = 6. This tool is valuable for engineers, hobbyists, and anyone working with microstrip. If there is an insulator around the wire then this calculator will be an estimate. W is the width of the microstrip trace. Differential Microstrip Impedance Calculators Giving Conflicting Answers. Differential Impedance Calculator. Increasing t decreases Zo, although it has small effect on Zo. Two of them is the following one : Calculate your microstrip transmission line; Calculate your microstrip transmission line; Its gives you the impedance based on different parameters. There are a lot of online trace impedance calculators specifically designed for differential traces. This is entirely different from leakage resistance of the dielectric separating the two conductors, and the metallic resistance of the wires themselves. The reason for this is that the conductor width scales with substrate height, so thicker substrates mean fatter conductors. Height. Following is the list of useful converters and calculators. D = trace edge to edge spacing. might have been the test equipment calibration, impedance mismatch amongst the measurement system’s cables and adapters, or trace impedance errors resulting from structural defects in the etched microstrip lines. Coaxial Cable Impedance Calculator. The Calculator Calculates the values of the Characteristic Impedance, Capacitance per unit length and propogation speed. coplaner waveguide spacing.