Thickness: Thickness of the microstrip conductor. Using the formula shown below, you'd find that the Q-section must have an impedance of 61. 1 is deceptively simple. 4 6. For a printed circuit board (PCB) this is a pair of traces, also known as a differential pair. Every transmission line in your PCB has a particular characteristic impedance and it is the ratio of the transmission signal’s voltage amplitude to its current amplitude as it travels over a conductor. 8) for the two configurations, transmission lines result in a larger bandwidth. 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. The input impedance is the ratio of input voltage to the input current and is given by equation 3. Impedance matching is important for the following reasons: maximizing the power transfer. 2. Impedance Calculation. The below step by step solved example problem may helpful for users to understand how the input values are being used in such calculations to find the lossless transmission line surge or characteristic impedance Z 0. Most RF Coaxial Cables have an impedance of 50 ohms or 75 ohms. In other words, if the load impedance is equal to the transmission line characteristic impedance, the input impedance will be likewise be equal to Z 0 regardless of the transmission line length A. X and B may each be either positive (inductor) or negative (capacitor). First, determine if the microstrip line is a suitable choice by analyzing the default microstrip transmission line at a design frequency of 1. 718. ). Find coefficient of reflection (mag, & angle) and SWR. This online microstrip impedance calculator calculates the characteristic impedance of the microstrip (Ω), W/H ratio, and effective dielectric constant (εe) by entering the value of dielectric material relative permittivity (εr),. Figure 3. 9 Ω and a negative imaginary part (–j99 Ω), we need a source impedance with a real part of 9. The Smith Chart achieves this by superimposing a grid on S11 that maps load impedance. εr is the relative permittivity (dielectric constant) of the transmission line material. Because designing a transmission line means you keep manipulating the characteristic properties of a twisted pair, to see which values will give the best results. Longer lines have more loss, but that’s all. 22, we considered impedance matching schemes consisting of a transmission line combined with a reactance which is placed either in series or in parallel with the transmission line. The result here reduces to any odd multiple of 1/8th the signal’s wavelength. Γ0 = Z01 − ZS Z01 + ZS Γn = Zn + 1 − Zn Zn + 1 + Zn ΓN = ZL − Z0N ZL + Z0N. Transmission line balun transformers are typically constructed of a transmission line such as a coaxial cable wrapped around a ferrite core, and in some cases merely air. For this to be possible, we should match the source and load impedances to the transmission line being used. We know that ZL in this case is 50 ohms, due to the. Characteristic impedance is purely a function of the capacitance and. 1 (a) presents the problem of matching to the input of a transistor which is modeled here as a capacitor in series with a resistive load. Assume microstrip line for which propagation occurs with wavelength 60% that of free space. e. In this case, the line length will always be 1/8th of the signal wavelength: Complex-to-real impedance transformer line length when the matching line’s impedance equals the magnitude of the load impedance. Series Impedance –accounts for series voltage drops Resistive Inductive reactance c. An impedance mismatch occurs when the transmission line impedance does not match the load's impedance. This calculator is designed to calculate the characteristic impedance of an edge coupled stripline. The microstrip is a very simple yet useful way to create a transmission line with a PCB. Single Stub Matching using parallel connection. Figure 5. Given impedancesZ, Z1 and Z2, deduce the lengths l1 and l2 of the matching sections. RF transformers are ideal for use in impedance matching to maximize the power transfer & suppress signal reflection, step-up/step-down. The spacing ( S) is determined. The voltage reflection coefficient Γ, given by Equation 3. I'm designing a circuit with RFICs using differential signaling. The required impedance and passband properties are attained by varying the number of sections or length of transmission line transformers. 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. Regier [6] gave a generalization that permits matching a transmission line of (real) impedance Z1 to a complex load impedance Z = R+iX,whereR is the load resistance and X is the load reactance. The CST Cable Studio Impedance Calculator can be started from Cables > Impedance Calculator. The end of the transmission line is hooked to an antenna with impedance ZA. 72mil. 1) describes the series connection of short- and open-circuited stubs having characteristic impedances of Z 0 / 2 and half the original electrical length. 3 3. 39 for the effective dielectric constant. Fig. Transform a Complex Impedance Through a Transmission Line Start with an impedance Z i = 27 + 20j ohms The normalized impedance for a 50 ohm line is z i = 0. It's also explained on our DK and DF Extraction page. The microstrip is a very simple yet useful way to create a transmission line with a PCB. A solution to the problems of microstrip is coplanar waveguide (CPW) shown in Figure [Math Processing Error] 3. 6. Mismatch Loss (dB) Γ = Z L-Z O Z L +Z O Where: ZL = Load Impedance ZO = Characteristic Impedance From the above equations, it can be seen that when ZL = ZO (Load impedance is matched to the characteristic impedance), the reflec- tion coefficient (Γ) = 0, making VSWR = 1. A shorted line is used in coax and parallel lines (less radiation) and open lines used inAn antenna tuner doesn’t change the antenna itself so much as changes its impedance to match the transmission line source, for example changing the impedance from 50 ohm to 55. antenna impedance, Za*SU, shunted by the inductance impedance, j X , of the short transmission line formed by the added gamma rod as seen at the input end of the gamma rod. , Z L), while we3. The same diagram and procedure can be used to terminate a drive and a load with different. This will also provide the time delay the cable provides for a signal and also the capacitance and inductance per. To simplify our analysis, we can model the input of the device receiving the power with it input impedance (e. In Figure 3. (1939). The surface finish is neglected. While transferring this energy, it is important to zero or minimize energy losses that occur. A classic example of an impedance mismatched circuitimpedance (2:1 voltage) transmis-sion-line transformer where the two pairs of cylindrical transmission line coils are connected in series at the input and in parallel at the output. Using a transmission line as an impedance transformer. For this to be possible, we should match the source and load impedances to the transmission line being used. Then use an L-pad calculator like this: - You can double check the formula derivation on that site. Example 3. 2000Ω (500 turns/1000 turns)2= 2000Ω (0. Instructions. On the wavelength scale, points z L and A correspond to 0. 7. Matching Pi Attenuator Calculator. X and B may each be either positive (inductor) or negative (capacitor). A shorted line is used in coax and parallel lines (less radiation) and open lines used in An antenna tuner doesn’t change the antenna itself so much as changes its impedance to match the transmission line source, for example changing the impedance from 50 ohm to 55. Microstrip Impedance Calculator. Matched impedance when Z0 = ZLÎΓ = 0 must get to origin of Smith Chart If not matched insert a matching network 1. Say the end of a transmission line with characteristic impedance Z 0 is terminated with a resistive (i. 1: 300 Ω 300 Ω twin-lead. A Clemson ECE635 Project by Adam Schreiber and Jason Byers. Transmission line calculator. These equations. They will give very similar answers. 1 Summary. The nice part about coax is that it can be bent and flexible unlike most pcb transmission lines. Although implementations vary, the wire diameter is usually about 1 mm and and the wire spacing is usually about 6 mm. Build a model from experimental data of impedance vs. Note the stub is attached in parallel at the source end of the primary line. The microstrip calculator determines the width and length of a microstrip line for a given characteristic impedance (Zo) and electrical length or. Here's a spreadsheet that performs via-hole inductance for microstrip circuits. 7). ; This formula allows us to determine the. In Section 3. This history of broadband impedance matching is organized chronologically by the birth date of each major design technique. This free online interactive Smith chart tool is a calculator which can help you design matching networks and obtain maximum power transfer between your source and load. the characteristic impedance of the transmission line. The radius of the circle is the reflection coefficient G , where the radius to the edge is 1. This online RF transformer calculator calculates the turn ratio (Np/Ns) and (Ns/Np) of an RF transformer by entering input/primary impedance Zp (O) and output/secondary impedance Zs (O). Impedance zL on the Smith Chart along with its constant VSWR circle. c is the speed of light in a vacuum (approximately 3 × 10^8 meters per second). Once the signals transfer to a transmission line mode, make sure that the drive, receiver, and transition line must have a constant impedance to avoid the. Admittance Base: The admittance base in. Example (PageIndex{1}): Matching Network Design Using Resonance. Transmission of electrical energy from the source to the load is done using a transmission line. 1 shows the two typical situations that arise. It’s crucial that the reactive components cancel each other. Then, simplify the expression inside the square root. Learn about why matching networks are used and how they are designed. A Transmission Line Connecting Source & Load We can think of a transmission line as a conduit that allows power to flow from an output of one device/network to an input of another. The right-hand side of Equation (5. The results show the input impedance input of the system, reflection coefficient between transmission line and load, VSWR of system. 16 a), filters, and other devices entirely from transmission lines, with fewer or. 1, which shows an impedance matching network placed between a load impedance and a transmission line. When you want to determine the width and length of a microstrip line for any given characteristic impedance and electrical length, or vice versa, a microstrip calculator is the right tool to do so. Overview. Secondary impedance, Z S: 2000Ω. In some cases, users require a custom impedance value. A λ /4 line is, in effect, a transformer, and in fact is often referred to as a quarter-wave transformer. 15. Can impedance matching? Impedance matching to minimize reflections is achieved by making the load impedance equal to the source impedance. Online VHF UHF. 7 (a)) ΔΓ = (Z0(z) + Δz) − Z0(z) (Z0 + ΔZ) + Z0(z) = ΔZ 2Z0(z) + ΔZ ≈. Single Stub Matching. Dielectric Thickness: mm. 24 ohms. The basic idea of impedance matching is illustrated in Figure 5. Maximum power is delivered to the load when the generator and the load are matched to the line and power loss in the line minimized. *Optimal D/d ratio for breakdown voltage is 2. Basic Appl. 2: A broadband RF balun as coupled lines wound around a ferrite core: (a) physical realization (the wires 1– 2 and 3– 4 form a single transmission line); (b) equivalent circuit using a wire-wound transformer (the number of primary and secondary windings are equal); and (c) packaged as a module (Model TM1-9 with a. 1. 3. Antenna Modelling with Numerical Electromagnetic Code. The simplest impedance matching case is when the real part of the load impedance is already equal to the transmission line impedance. The width of the conducting layer is important to calculate the radiation intensity since it directly affects. a. 2 are defined as. A two-port impedance model represents the voltages of a system as a function of currents. An open circuit, which is difficult to realize, can also be used in this. "Series-Section Transmission-Line Impedance Matching," QST (July, 1978), 14-16. This code let you calculate the value of some of the parameters in circuit impedance analysis. If the calculator does not provide velocity (or velocity factor), it's probably because you can use e_eff instead. load impedance L Z. Single Stub Matching using parallel connection. There are many different designs of matching networks for different impedance and power levels. Load in ohms. The K values for the various transmission lines are also copied from his Transmission Line Details windows. Relative Dielectric Constant ( εr ): Track Width: mm. The quarterwave impedance transformation calculator is used to match an input and an output impedance at a given frequency for maximum power transfer. Press Analyze to see the results. Depending on circuit sensitivity, the distributed model for transmission lines starts deviating from the simplified lumped element model between line length of 0. When a transmission line is terminated by a load precisely matching its impedance, there are no reflected waves and thus no problems with line length. between a t ransmi ssion line of characteristic impedance Z o and a real load i mp edan ce R L1 yields a matched system. Therefore, next part is divided in two parts as detailed below. 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. Based on the number of stubs used, the stub impedance matching can be. A great example is the surface microstrip which forms on the outer layers of the PCB. The functions reflcoef( ), lineleng( ), zin( ), yin( ), and vswr( ) are created. This allows us to use a single transmission line element as the impedance-matching network. The free end of the stub is either left open-circuit or (always in the case of waveguides) short-circuited. The condition of reciprocity or symmetry existing in a system can be easily identified from the Z-parameters. L networks for narrowband matching a source or load impedance Z to a transmission line with characteristic impedance Z 0. Figure (PageIndex{1}): Matching problem with the matching network between the source and load designed for maxium power transfer. Reflection-less match. 6c respectively. RF impedance matching can be implemented in two different ways -. It’s particularly useful for determining the characteristic impedance. tline makes use of gnuplot for visualizing its. 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. 6. Let’s assume that the. EEWeb offers a free online twisted pair impedance (transmission line) calculator. The ultimate example of this is a transmission line of infinite length: since the signal will never reach the load impedance, the source only “sees” the cable’s characteristic impedance. tline is intended to calculate various transmission line parameters. The effective dielectric constant drives the length of the taper, this effect was not. In Figure 6, we implicitly assumed that the impedance of the signal source (not shown) is matched to the line characteristic impedance. ; Z 0 is the characteristic impedance of free space (approximately 377 ohms). In Figure 3. Design a match consisting of a transmission line in series with a single capacitor or inductor that matches a source impedance of 50Ω to a load impedance of 33. Asymmetric and symmetric versions of a stripline can be implemented with this calculator application. So for the load it is obvious why 50 ohm is needed, but why for the source? I would get more power transferred to the transmission line (or load), if the source impedance was say 10 ohms. 5mm pitch. 3. 1: Impedance-matching using a quarter-wavelength transmission line. In this case, the line length will always be 1/8th of the signal wavelength: Complex-to-real impedance transformer line length when the matching line’s impedance equals the magnitude of the load impedance. It consists of a transmission line with a sliding short circuit (similar to a trombone) that can be used as the reactive element in the impedance matching method shown in the Smith charts above. 1: Impedance-matching using a quarter-wavelength transmission line. The default units for all given values, except the. I know that usually transmission lines are connected in delta and I know how to calculate the impedance in each phase. Try This New Tool. 6. Suppose that Zg=50 Ohms, ZA=50 Ohms, Z0=200 Ohm, and that the line is a quarterwavelength long. 7 gives 49. Output-Damping Resistors. This calculator finds both odd and even transmission line impedance. com. The characteristic impedance (Z_0) associated to a transmission line (or any continuous media supporting the propagation of electromagnetic waves) is defined as the ratio of the (forward) voltage and current when the transmission line is infinite (i. V~(z) = V~+ 0 (ejβz +ΓLe−jβz) I(z) = V~+ 0 Z0 (ejβz − Γe−jβz) (1) (2. This can be built into a FLEXI-BOX and a transmission line (50 Ohm track) PCB is available which easily adapts for this circuit with one simple trimming. Return loss is an important parameter to measure in transmission systems because it can affect the system's performance. 54 + 0. R R1 Zo( ,L) C L 1 (a) (b) Figure 7. 301λ can do the job. Plot input impedance for a range of frequencies. 1- Assume the load is 100 + j50 connected to a 50 ohm line. In solving problems around matching, the smith chart is used to determine the value of the component (capacitor or inductor) to use to ensure the line is perfectly matched, that is, ensuring the reflection coefficient is zero. 3. For example, given a type of cable and a known load impedance, tline can calculate the impedance at the input of the cable. Impedance Analysis Calculator. This tool is javascript so it works on Windows, Mac, IOS, Android. g. on the line. Figure 1-1: A load connected to a transmission line through a matching network. Frequency-dependent transmission line behavior can also be introduced by loss, as discussed in Section 8. 7. It's just as useful today, more than fifty years later. Assume source impedances match their respective transmission lines Z1 Z2 Linear Network Transmission Line 1 Transmission Line 2 Z1 V in1 V in2 Z2 Same value by definition. At this point, it has been carried out a general analysis to determine the. The edge couple differential microstrip transmission line is a common technique for routing differential traces. Is it matched well? 2- For a 50 ohm lossless transmission line terminated in a load impedance ZL=100 + j50 ohm, determine the fraction of the average incident power reflected by the load. In general, θ = ( π / 2) ( f / f 0). Impedance Matching Transmission Line. Antenova's Transmission Line Calculator Due to the additional feed track dimensions, matching impedances via GPCW feed lines is a complex process. Generally, the cable manufac-Online calculators will generally use Wadell's equations to determine the transmission line impedance numerically. = √ (L/C)A microstrip width calculator can calculate the width of a microstrip. It would be very helpful if we could determine the input impedance of this line, which is simply the impedance at the input (left) end. microstrip; analyze (stubTL4,freq); Z0 = stubTL4. 23. ( 9) Rotational and periodic motion ( 17) Thermodynamics ( 31) Waves ( 14) ( 33) Using this impedance matching calculator, you can find the electronic components' appropriate values in the L-match, Pi-match, or T-match networks. 3. 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. 0. 32GHz FEA model using ANSYS HFSS. The impedance seen by the source is simply given by Z= jωL+ 1 jωC +R= R+jωL 1− 1 ω2LC (7. We don't post IEEE papers on line because that would violate their copyright, but if you're clever at. Using the expressions for the impedance of an open-ended or shorted transmission line segment of length L given earlier in this tutorial, the equations for the length L s of the open stub or short stub are found as: Bopen = Y0tan(2πLs/λg) = −Bin B o p e n = Y 0 t a n ( 2 π L s / λ g) = − B i n. Impedance (Z) at any single point on a lossless transmission line (for stub. The result here reduces to any odd multiple of 1/8th the signal’s wavelength. 16. stubTL4 = rfckt. For example, should L2 return a value of -62 degrees, the correct result will be. For each case, we use a different cable impedance formula: To calculate the impedance of a coaxial cable, we use the following formula: Impedance = 60 × ln ( D 2 / D 1) ε r. Solved Example. In Figure 3. If you try to find the admittance of the load with the series transmission line at this point, you get something like: YL = 1 50 + jK = 50 K2 + 2500 − jK K2 + 2500 Y L = 1 50 + j K = 50 K 2 + 2500 − j K K 2 + 2500. This tool calculates the matching network necessary to terminate a line of the specified characteristic impedence (Z o) in a specific complex load impedence (R L + jX L) at a specified frequency. Matching seems like a trivial exercise when you’re dealing with a theoretical circuit composed of an ideal source, a transmission line, and a load. Both the input reflection coefficient and the load. Calculates the resistance, inductance and capacitance per unit length of common low-loss transmission line configurations. Coax Impedance Calculator. The calculator produces more accurate results than the IPC formulas for impedance because it. The formula for S11 treats the transmission line as a circuit network with its own input impedance, which is required when considering wave propagation into an electrically. The MWI-2017 Microwave Impedance Calculator software doesn’t. On the other hand, 75 Ω products are best suited for applications that involve transmitting or routing video signals (e. With a two-section cascaded quarter-wave transformer an appropriate matching network is shown in Figure 7. There are four different types of impedance used in characterizing differential trace impedances. Click the Z_Load buttons to see impedance examples; A Match is at dead center (reference impedance Z0 ) A Short is at the far left; An Open is at the far right; Pure real. Reactive Match Calculator . Stick in a second transmission line that acts as L or C called a stub. Calculate impedance, reflection coefficient, transmission coefficient, and VSWR. With double termination, both the source and the load are termi-nated with that impedance. 57 pF can be used. 1. The simplest termination is either a short circuit or an open circuit. This objective is the target of the circuit design. 23. Design a transmission line segment that matches 300 Ω to 50 Ω at 10 GHz using a quarter-wave match. Reflection-less match. The source has the equivalent impedance of 50 ohms. 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 ground plane. You can plot the VSWR circles. Maximum power is delivered to a load when the transmission line is matched at both. Figure (PageIndex{4}) Solution. Equation Source: Ulaby "Fundamentals of Applied. If you are using a two-dimensional formula (i. Overview. Examples are shown plotting reflection coefficients, impedances and admittances. It supports both balanced and unbalanced lines. 450 Ω balanced transmission line and a 120 ft dipole antenna 30 ft above ground. Source voltage. In other words, if the load impedance is equal to the transmission line characteristic impedance, the input impedance will be likewise be equal to Z 0 regardless of the transmission line length A. In transmitting systems with an antenna separated from the transmitter and connected to it by a long transmission line , there may be another matching network (ATU) at the antenna that matches the transmission line's impedance to the antenna. 3 and 12. Note that if the trace is longer than its critical length, it should be treated as a transmission line with a controlled impedance. this real impedance will match Z o. The transmission line is a two-port circuit used to connect a generator or transmitter signal to a receiving load over a distance. Calculate Reset Result Characteristic Impedance ( (Z o) Ohms Formula for Quarter Wave Transformer Impedance Calculator Derevation of the Quarter Wave Transformer. Back in Chapter 3, we discussed characteristic impedance, transmission lines, and impedance matching. Adapted from model by Roy Wastie Sam Henry 5 July 2017. Also, what is theECE145A/ECE218A Impedance Matching Notes set #5 Page 13 Basis for distributed matching using transmission line segments: the equivalent circuit model of a short transmission line. It consists of a quarter-wavelength transmission-line, whose input impedance can be easily calculated using the expression. Solved Example. Topic 56: Characteristic Impedance One of the most basic parameters of a transmission line is zo, its characteristic impedance. Series Impedance –accounts for series voltage drops Resistive Inductive reactance c. To find the length of the stub, we should consider the impedance of point A. These quantities - source impedance, line impedance and load impedance, respectively - must equal one another (impedance matching]) to ensure the efficient transmission of power. Use of a Transmission Line in the L-Section As can be seen from the computed selectivity curves (Fig. 23. For arbitrary lengths of transmission line it is more complex, but if you. "Series-Section Transmission-Line Impedance Matching," QST (July, 1978), 14-16. The short-circuit jumper is simulated by a 1 µΩ load impedance: Shorted transmission line. I am planning to use coplanar waveguide with bottom ground layer as transmission line. 1- Assume the load is 100 + j50 connected to a 50 ohm line. Impedance Base: The impedance base in Ohms. Coaxial Cable Impedance Calculator. 13. The condition for reflectionless matching in. Some calculators will allow you to calculate trace impedance in a number of geometries, e. To design fully transmission-line matching circuits, we have to first learn how to replace the lumped element in the matching circuit from the last step in the previous section with a transmission line. The microstrip calculator determines the width and length of a microstrip line for a given characteristic impedance (Zo) and electrical length or. Single Stub Matching of a Transmission Line Introduction A single short circuited transmission line is a distance d from the load and of length d. Transformers are used to match one impedance to another (from Z1 to Z2). 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. This property of open- and short-circuited transmission lines makes it possible to implement impedance matching circuits (see Section 3. Such equipment is best suited for communications applications, which make up the bulk of RF applications. e. The quality of an impedance match can be expressed mathematically by the reflection coefficient (Γ). . The input impedance of a short- or open-circuited lossless transmission line alternates between open- ( Zin → ∞ Z i n → ∞) and short-circuit ( Zin. If you use the 1/4 rise time/wavelength limit, then you are just guessing at the. Transmission Line Calculator March 6, 2007. There are four different types of impedance used in characterizing differential trace impedances. Impedance matching is one of the most important practices in wave engineering as it enables one to maximize the power transfer from the signal source to the load in the wave system. In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. The lateral dimensions, however, are well controlled being photolithographically defined and then etched. 19. In coaxial cable or two-wire line applications. In terms of the characteristic impedance. 4. ; Er is the relative permittivity (dielectric constant) of the substrate material. The edge couple differential microstrip transmission line is a common technique for routing differential traces. stubTL4 = rfckt. e. Simply put, differential impedance is the instantaneous impedance of a pair of transmission lines when two complimentary signals are transmitted with opposite polarity. With the (antenna + impedance matching network) designed to match a target impedance of the feedline, the next step is to ensure the input impedance also matches 50 Ohms. No matter what impedance-matching scheme is chosen, the termination impedance to implement must be accurately calculated. The average amateur does not like to. Even and Odd Mode Impedance. ; H is the height of the dielectric layer (in meters). Once the dialog is open a segment to use for the impedance calculation can be defined by either: Selecting it in the dialog opened by "Segment List". Transmission line equivalents—All designs using lumped elements may use transmission line elements, as. 45 GHz. This seems to be a point not fully resolved(inductors and capacitors), transmission line and impedance transformers. Transmission line matching is not to beAgain, we will look at a transmission line circuit in Figure 1 to find the input impedance on a transmission line. Picking from the CST Cable Studio Segments Navigation Tree. The tool implements numerical solutions of Maxwell’s equations to render accurate and consistent results. Step 2: Use a shunt (series) reactive element to resonate with (or cancel) the imaginary part of the impedance that results from Step 1. This transmission line calculator calculates the impedance at input and attenuation of a given transmission line once terminated with the given load. the transmission line characteristic impedance 0 Z. To locate this point the arcs corresponding to the real and imaginary parts of (z_{L}) are considered. 1. Altium Designer’s differential line impedance calculator will set up your impedance-controlled differential pair routing widths for you. Here, the antenna impedance matches the transmitter output impedance. In DC circuits, the source and load should be equal.