50 ohm trace width fr4. 8 Characteristic Impedance: 50 With my values, with a non-standard thickness board (31 mils thick), I arrived at 55 mils. 50 ohm trace width fr4

 
8 Characteristic Impedance: 50 With my values, with a non-standard thickness board (31 mils thick), I arrived at 55 mils50 ohm trace width fr4 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

The IC only has room for 18. A targeted impedance on a PCB trace can be attained by varying its width. Note: ρcopper = 1. Enter a 7-digit number in our reverse phone number. 5x trace width is a typical starting. > >> > >> The length of the 50 ohm RF trace ( CPW - 15 mil trace width & 18 mil > spacing to ground ) , > >> is approximately 5 cms . View All Tools. Impedance Calculation for PCB Designers - Altium. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. For a transmission line of a given line width, the closer the distance to the plane is, the corresponding EMI will be reduced, and the crosstalk will also be reduced. I do not know the Dielectric Thickness or constant but is that posible just to add in the notes as something like "Please select a FR4 board where a coplanar waveguide, track width 1. aholtzma • 3 yr. Gen2. 6 mm • 2. 27 mm, gap width 0. 2mm, it may be better idea to use microstrip line, with. Larger ground clearance lowers capacitance, increasing impedance. ( 2. 0014″. with the following layout parameters (width|space|width): Ohm. 62, ER 4. 9mm. Resolutions ~164 mils (FR4) * Connectors: SMA; 1MHz repetition rate – maximum cable length exceeds 50m; DC Input Power: USB Type C 5V 118mA typical. Where electronics enthusiasts find answers. 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. How can I correctly make connection between some small components like capactiors and IC's to such wide lines? It's almost 3mm wide lines. Among these 3 variables, the trace width I the one that is within the complete control of the designer. 6 nH. The above data is compiled for FR4, which will cover a broad range of PCBs sent to production. 6mm FR4 board, is about a 2. 73mm, and the pitch of the LQFP-144 is 0. 29 mm width traces to obtain 100 Ohms ZDiff while using 0. That magic 50 Ohm is calculated from ZL=sqrt (L'/C') of the transmission line, where L' and C' are capacitance and inductance per unit length. 7mm is correct for 1. Without truncated corners, the array has a single resonant frequency at 2. Search top-rated Class A, B, C, & towable RVs from just $35/night. On standard FR4, a 100 MHz signal wavelength is about 8. The microstrip is a very simple yet useful way to create a transmission line with a PCB. FromThis calculator is designed to calculate the characteristic impedance of a microstrip - a flat conductor suspended over a ground plane with a dielectric between them (see diagram below). There are some advantages to using a microstrip transmission line over other alternatives. The power is just 10mW. The problem with this stackup is that to achieve 50 ohm routing, the width required on the top layer is 396µm (approx 18mil), which is quite a. 8. Therefore, the trace height and width you choose for 1 GHz will be a slightly different impedance at 10 GHz (if you need to worry about the difference, you probably already know about the difference!) If the line length is not << wavelength, you should try to design the line width with proper line impedance. I need a Z0 of 50 ohms. 0 up to 4. The second thing is that currents are not going through the coper but at the edge between coper and substrate and last your tracks should have a width that is giving your 2. I am using 0. However, the capacitive coupling between the trace and signal could be weak and there is no guarantee of a large reduction in EMI. Surface resistivity is expressed in units of ohms or ohms per square. In the analysis shown in Figure 2, every 1000 mils (1 in. Back drill pin count : 156 pins. dielectric constant er is 4. For example, high speed designs will typically always keep power and ground planes on adjacent layers for decoupling and. 1524 mm) minimum trace spacing; Note that this is a 2-layer board! Routing differential pairs on a 2-layer, 1. For instance, FR4 board materials have dielectric constants ranging from 3. 8. This comes from electromagnetic theory and is usually applicable to RF and high frequency applications. (90 Ohms) on 2-layer FR4 board. 0. 8 mil traces, and that is assuming no space between. The trace impedance (Z) of a PCB trace can be calculated using the formula for microstrip transmission lines: Z = (87 * Log10 [ (2 * H) / (0. 5 oz Cu Microstrip with H = 2 mil 25 50 75 100 23 4 5 Line Width (mil) Impedance (Ohms) Low DK Flex: DK=2. \$\begingroup\$ A trace on FR4 of dielectric thickness t above a ground plane will present a suitable 50 ohm impedance if it has a width of 2t. dielectric height is a standard 2 layer board, it is 1. 03 10. This is best summarized in a graph. 5mm FR4, but be careful with discontinuities at the connectors. Hello, I want to calculate the approximate trace width for a 50 ohm trace. Therefore it would require ~10 kV to break down 20 mils of FR4. 4 DisplayPort Parameter Value Frequency DisplayPort 1. This is one reason you should leverage your fabricator's experience and material set when designing the stackup and determining impedance. 8 mils is a standard range for solder mask thickness; Altium Designer uses 0. The characteristic impedance of the signal path is a continuous 50 ohm path relative to the closest ground. The down side is that for thin tracks, it is very hard to get controlled 50 Ohm impedance. ArchiveSparkFun Forums . I don't. Share. Home. I am designing a USB-hub that has many USB traces. 75 ohm at ambient temp and 0. crutschow. Note further that, for standard fab widths (minimum trace width) and component pitches (maximum practical trace width), you can't get impedances very low on two layer board (even 0. As a good rule of thumb, a 50-Ohm microstrip in FR4 has a line width twice the dielectric thickness. 9 x 10-3 ohm/ohm/C. From the performance of PCB traces, low impedance is generally better. Close to get exactly 50 ohm you need 2 mm trace width . board materials have distinct dielectric constants, which are related to the resin materials used. 4. 3 as fr4 material with 1. Now. So, for example the length for a 100 ps delay with FR4 is. You can use our calculator to determine various trace components, such as trace temperature, maximum current, resistance, voltage drop and power dissipation. , when its width was set to the same width of the 50 Ohm input lines (13 mil). You might want a certain trace width and. It is also easy to find parts (such as filters, amplifiers, antennas, etc) with 50 ohms characteristic input/output. resulting impedance for this microstrip would be about 50 Ω. 1/2Oz copper 1. 4) requires a 5. The optimum gap was found to be 5. 00 8. Here D is the conductor. PCB Stack Specifications Parameter Values Solder Mask (SM) 0. 2mm. If you're routing with 50 Ohm impedance and you need to design a 4-layer. Common consideration The impedance of the line is mainly depending on your. Now you try it: 1. 0001, 3um gold, conductivity 3. My 50-Ohm trace is on component side and the ground layer is the next layer (10-mil distance). I made a small 4 layer 1. 0008). 5 mil trace width for differential impedance of 95 ohm and 9. 5 mm Track= 2. A higher scale works, but avoid moving into a scale close to 1k ohms or higher. Microstrip dielectric losses are fairly consistent with width for 50 Ohms, but the conductor loss varies considerably. 149 Roms Jr Hindi Typing Tutor Download Ditari I Ana Frankut Pdf Fifa 15 Pc Download Torrent 14 Line Quran Taj CompanyEach square has a resistance of 1mΩ, so the total end to end resistance of the trace is 10 sq × 1mΩ = 10mΩ. All 4 layers had ground pour on them. In order to avoid the long power line acting as an antenna, an ferrite bead is used as an rf choke. (90 Ohms) on 2-layer FR4 board. Trace 1 (TP1/TP2) – Single ended 50 Ohm trace; Trace 2 (TP3/TP4) – Single ended OhmBeatty standard; Trace 3 (TP5/TP6) – Single ended trace with two impedance steps 3000 mils apart. Is there any proper way to use such connectors. 5 equal-ripple when the order(N)=3, center frequency=2GHz, bandwidth=10%, Zo=50(ohm) and attenuation at 5 GHz - many of you will find this problem familiar since it's from Pozar's microwave engineering textbook. You can access serveral online sites to help calculate a trace with Z0 of 50 Ohm. Line Spacing: 4mil (0. Where electronics enthusiasts find answers. 378 [mils/oz/ft. 1 Impedance PTN33xx and CBTL061xx I/O impedance is targeted at 50 Ω single-ended and 100 Ω differential. Hence, an antenna with 50 % efficiency has a ratio of 0. 5 and 1. By understanding the microstrip transmission line. 4: 4. To avoid microstrip line modes, it is recommended that h >> b and that the component side ground extend away from the. This page covers Microstrip Width Calculator. The variation in FR4 dielectric constant vs. 0 up to 4. You will have a 50 ohm line. Relationship between the crown width-diameter ratio of white spruce trees and stand density, age, and site in the interior of British Columbia. FR4 is the most common grade dielectric material that is used in the fabrication of circuit boards. Common consideration. -1, Can. 4GHz, a 5mm length of 1mm track is about 25 degrees. 3. Re: Max current density for 35 µm Cu FR4 PCB? « Reply #3 on: March 19, 2015, 09:48:14 am ». When I designed the testers, I usually chose 90 ohms; lower current yet and it's close to ribbon cable (~100 ohms). Unfortunately, however, I am not using FR4. Book the best motorhome and trailer rentals in Victoria, BC on RVezy. Where: H is the height of the PCB above the ground plane. Assuming a 10 mil dielectric thickness, a 50 Ohm trace width can be anywhere from 30 mils to 16 mils for a dielectric constant from 2 to 5. e. An 8mil wide trace, at low frequencies, made of 1oz copper (1. Set your multimeter to an ohms scale around 100 ohms. Where I is maximum current in Amps, k is a constant, dT is temperature rise above ambient in °C, & A is cross sectional area of trace mils². trace thickness = 0,2 mm (from pcb datasheet) height of dielectric above return plane = 1,6 mm (from datasheet) I obtain a Z0 of 70,8 ohm. I use a 4-layer board on my M12. Where electronics enthusiasts find answers. 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. Learn how to. Resistivity of copper foil = 1. Impedance vs Line Width at 10 GHz 0. 376V, before it gets disturbed. 10: Threat frequency versus substrate thickness for the lowest surface wave mode coupling to the quasi-TEM mode for the three materials, Teflon, Rogers Duroid 6002, and FR-4. PCB Antenna: This is a trace drawn on the PCB. If we make the line width wider, we have to make the dielectric thicker to preserve the 50 Ohms, and this keeps the loop inductance the same. 6mm will be about 3. 031” FR4, the max. 55 mil should give 50 Ohms. 6mm. (2 layers board, 1. The width of the strip, the thickness of the substrate,. 5mm FR4, but be careful with discontinuities at the connectors. When these waves get to the end of the line, they may find a 50 ohm resistor. Check the stackup with your pcb manufacture. Remember, these stackups aren’t for every design. FR4 laminates can have Dk ranging from about 4. 4mil required impedance 50 Z frequency 100Mhz calculated width of trace = 110 Mils This says that ALL 50 Ohm transmission lines in FR4 have exactly the same loop inductance per length. 0065" Bottom Layer: 0. If we make the line width wider, we have to make the dielectric thicker to preserve the 50 Ohms, and this keeps the capacitance the same. 6mm thickness and the connector is a SMA. 44 x A0. 0 requires 90ohms differential impedance (max 45ohms per track) Max trace-length mismatch between High-speed USB signal pairs should be no greater than 3. 10. The above screen shows that the target parameter is 'Trace Width (W)' and the fixed parameters are 50 ohm Char. Relative_Dielectric_Const depends on board material and is ~4. The PCB material will be FR-4 with 1. Figure 1. With our 500 ps rise time for the High Speed spec, this gives a signal propagation distance. For the signal trace of width W and thickness T, separated by distance H from a ground (or power) plane by a PCB dielectric with dielectric constant εr, the characteristic impedance is So i want to know that how to calculate 50 ohm transmission line trace width. You only need to worry about trace impedance matching at high frequencies, where the propagation delay of the trace length becomes a significant fraction of the waveform time period for one cycle of an RF signal or a significant portion of the rise-time for digital signals. If we make the line width wider, we have to make the dielectric thicker to preserve the 50 Ohms, and this keeps the loop inductance the same. strip thickness is 1 oz copper, 0. T=trace height . By understanding the microstrip transmission line. I am routing a PCB that will use a GPS antenna, and I need to use a 50 Ohm trace. For example, (50~Omega) on commonly-used 1. 5 for FR4. 4. 500000 Permitivity of Fr4 = 4. Pad Stack Calculator 4. ) of FR4 PCB trace (dielectric constant Er = 4. Eq. Activity points. Quartz, H=254 um (10 mils), W=540 um, ER=3. The dielectric constant Dk can range from 3. Also the size of the board is large compared to what I am looking at. 6mm boards at essentially the same price as standard pcb and, the shipping will be lower than standard PCB because. 4mm PCB for a trace width of 0. 5. Your job is to match this to a patch antenna with an impedance of 100 Ohms. Re: How to calculate difference mode trace with 100ohm imped Hi These datas are insufficient to calculate the Impedance. The goal is, of course, to get as much bandwidth as possible, but realistically I'm shooting for a minimum of ~1 to 250 MHz. 024 x dT0. 4mil. User mini profile. 025mm change of track width, there is a 5-6 ohm change in impedance. Here are a few qualities of FR4 materials that make them popular: Wide range of operating temperature (50°C to 115°C) Higher T g value (about 180°C)Microstrip lines have three parameters that we can change to achieve 50 ohm impedance: copper thickness (T) substrate thickness (T) track width (W) Due to design constraints, there is only one parameter (track width,) left to achieve 50 ohm. 5mm wide (over 0. 4Ghz speeds, using a 5mil-thick FR4 dielectric, with an underlying solid copper reference plane. If room is limited, it may be helpful to add ground at both sides of the signal lines, making differential surface coplanar strips with ground. For a 1 inch trace, this value would have a total inductance of ~7. Thickness: Thickness of the stripline conductor. It’s a three-in-one calculator. In that case I need to design a transmission line which has characteristic impedance of 50 ohms. Aug 24, 2012. 2 mm. If you’re routing with 50 Ohm impedance and you need to design a 4-layer stackup, read our guide to see some standard constructions and PCB trace widths that. 50 Ohm Pcb Trace Width Calculator Bully Zip Download Macbook Air M1 The Sims 4 Adobe Acrobat Pro 11 Free Download Full Version Crack Ibwave Crack Download Keygen Autocad 2020 64 Bit. 363A, 1oz, 20c gives 5 mil. So this is a diff pair with a Z of 90 Ohms. 0 ohms; even impedance: 38. Unfortunately, however, I am not using FR4. 004 range There is demand for flex materials with low dielectric loss. Its 4 layer card with 2 power plane in inner layer. resistance of the PCB traces plus the 10 Ohm resistor. e. The input impedance, Zin, of the shorted microstrip line is shown in Figure 3. Feb 5, 2020 at 8:51. = room temperature (25⁰C) L= Length of trace. This has always worked fine in my projects: FR4 PCB 2 layer, 1. o 85 ohm differential impedance o 7 mil trace width o 2 mil trace copper thickness o 5 mil center-to-center spacing o 4. Seeed Fusion promises mature PCB manufacturing and fabrication with low costs, quick build time and 100% quality guaranteed. Where electronics enthusiasts find answers. 36mm. 8 mil Bottom Cu+Plating 1 OZ/1. I need a Z0 of 50 ohms. Typically, this will be 35 or 70 microns depending on how the stack-up is defined. Microstrip Impedance Calculator. 5GHz. If you are using GaAs, Er=12. Trace Impedance 100 Ω±15% differential; 50 Ω±15% single ended 2. 5 Ghz ) on a Fr4 > substrate . 2 mil trace width o 2 mil trace copper thickness o 5. 1 mm FR4 between Top high speed lines and next ground plane. The physical parameters of the trace i. 4 ohms; differential impedance: 90. 2. • FR4, 4 layers, PCB Thickness: 0. . In my layer stack manager, I have the following: Note that Altium calculates that the trace should be ~100 mil wide, which is significantly higher than what the datasheet suggests (0. To achieve 100 ohms with 1. Since characteristic impedance of CPW is Zo= 50 ohm which is connected to load of ZA=50 ohm, using the following below relation, Zin should be always 50 ohms irrespective of βL based on mathematics as numerator. Test Circuit However, it takes a finite time for a voltage step to propagate along a PCB trace, and if you could measure the initial instantaneous impedance before the test voltage reached the resistor, then it would read ~65 Ohms. εr 14 RF / Microwave Design - Basics)Sometimes Dielectric surrounding Trans-mission Line isn’t Constant (Outer Layer Trace on PCB). When the termination resistor matches the track impedance, there will be no reflections. ρ– Bulk Resistivity of Copper (6. , si-list at FreeListsWe’ve compiled a list an IPC-specified PCB trace width vs current table in this post. Using such an impedance controlled line matters where the line length is longer than 1/10 of a wavelength. I made a small 4 layer 1. 15 mm and separation 0. Aug 24, 2012. Also, standard FR4 is very lossy at GHz frequencies. Also, standard FR4 is very lossy at GHz frequencies. Adjust down by 95% to 98% due to the solder mask to get 50. (because the filling factor is 50%), and that of free space. Where: R– Trace Resistance in Ohms. 4, loss tangent = 0. 9mm. 3mil Metal 1 1 OZ/1. If the length of the trace is also provided, the total resistance, voltage drop, and. Advertisement. Thinner trace widths come with higher impedance, while wider trace widths come with lower impedance. If im using an FR4, how much loss can i expect with a 60ohm 1inch trace vs a 50ohm one? If i have a 2inch trace and a 4Ghz high band antenna matching…The Datasheet says that the target impedance of the RF Trace should be 50 Ohms as a controlled impedance. , 0. 048 x dT0. The surface resistivity of the most commonly used PCB material FR4- for example FR370HR- is 3. Co: capacitance per unit length. 75 ohm at ambient temp and 0. Assuming a 10 mil dielectric thickness, a 50 Ohm trace width can be anywhere from 30 mils to 16 mils for a dielectric constant from 2 to 5. This article explains about the calculation of antenna input trace width considering 50 ohms characteristic impedance (Zo). Design a 50 ohm impedance microstrip line for RF signals The main difficulty is to be able to create a trace up to 3 mm large when you have as a source and. With practical linewidths it almost impossible to get an impedance outside of the 25 to 100 ohms range. This is approximately double the cost of FR4 PCB material, but can provide increased eye-opening performance when longer trace interconnections are required. At 100MHz that will not be super critical if the trace is not too long compared to the wavelength. If output power is per tone, then. W=trace width. Figure 11. (We can process . And I got 24 mils for the 100 Ohms differential traces from IC to balun, and 55 mils for the 50 Ohms trace from balun to antenna. 0001), and because it has low dielectric constant the line widths for 50 ohms are much fatter than other substrates, which reduces metal loss. 6 mil wide 50 ohm trace. Note: ρcopper = 1. 4 Ghz & 5. 6 mil "measured copper top to bottom" er of FR4 = 4. the stripline hits ~50 Ohms over a narrow range. 5 or -3 dB. (Figure 4. 4852 5-star. The width of the trace does have an impact on. Trace Width: Leave this blank so it calculates it. Finally, make sure to connect the GND planes with a via nearby wherever a signal transition is made. 50 Ohm Trace Width Calculator Psp System Update 6. 22 mm; trace. , si-list at FreeLists[SI-LIST] Re: Inserion loss of fr4 , 50 ohm trace . 4 and Bluetooth low energy applications built on FR4 substrates, the methods of transmission lines typically take. Trace thickness is 1. Heat is dissipated through conduction, convection, and radiation. Dielectric constant is 4. are identical to FR4. 1). I wanted to use Altium to calculate the width of the trace automatically, so that it had a 50 Ohm impedance. 45 GHz (BLE basically). The impedance of this line in ohms can be estimated with Eq. 1 Answer. When I use Jean Nicolle calculator Z0=89. 58 -> digged this out from seedstudio fr4 spec documents Dielectric thickness: 0. A 50 ohm trace (CPW, minimum clearance) is about 1mm wide, on 1. The legend for all three curves is shown on the middle curve and that is a transmission line built on a 10mil thick RO4350B. But if that is what you have, and with FR4, your microtrace width should be around 1. (FR4: 4. 9 pF would have a similar . Standard FR4 1. Placing the driver or receiver close to the connector, so the length of mismatched 50 ohm trace is very short solves this problem without requiring a 72 ohm trace on the PCB. I'm trying to design a coupled line BPF 0. Just a clean step. 8 Characteristic Impedance: 50 With my values, with a non-standard thickness board (31 mils thick), I arrived at 55 mils. Since my layer thickness is 0. 38 GHz. And yes, its very wide. 5 (assume 4,35) ; for 868MHz. So, for example the length for a 100 ps delay with FR4 is. 6e-3 m and 1″ = . If it were built in ½ oz. (M6), Elite EM-355D with FR4 laminates; 2. 4mm pour 50 Ohms impedence. 4 mil. Sierra Circuits’ Trace Width, Current Capacity and Temperature Rise Calculator is an advanced PCB tool that works based on the latest IPC-2152 standard. Relative_Dielectric_Const depends on board material and is ~4. 17 pF per inch will not provide much inter-plane capacitance for supply decoupling. The next graph investigates this further. According to JLCPCB's "impedance calculator" for their JLC7628 stackup, a trace of 11. It is always a compromise between trace impedance, trace width and prepreg/core thickness and it is best to use a stackup calculator to provide quick ‘what if’ analysis of the possibilities. If we were to use the 8. 811 in/nSec (speed of light, in inches per nanosecond). 65mm wide trace, with continuous ground plane underneath. 5 typical "Check data sheet first, make note of intended frequency of use" trace thickness 1. Phone Number e. 003-0. If that thickness of FR4 is changed from 10 to 6 mils, the impedance will only be about 36 ohms. Home. 2 W HMy layout designer is saying the manufacturer has to put a 50 ohm trace for the u. The ideal microstrip width to depth ratio for a 50 ohms FR4 material is about 2:1. The dielectric constant of a material IS slightly frequency dependent. 3mm material as well? Or a tool to calculate? Thanks a lot! Jorg. So, you need to calculate how much resistance a PCB trace can provide. Then it will reflect off and run to the 50-ohm connector on PCB, then it will reflect off from the connection of PCB line and 50-ohm connector despite any of my impedance matching actions. 946 for silver, or 1. o 100 ohm differential impedance o 4. 8 mil trace width over ground plane. For example, there are a few factors that will limit your available trace width to get to 50 Ohms in a 4-layer stackup: Available materials: Remember that FR4 laminates do not have a specific dielectric constant (Dk) value, and this value is a big determinant of your trace impedance. After quite a reading I got to know that as the track width of a cline is decreased, there is a decrease in the impedance, Trace width is indirectly proportional to impedance. According to their 2 Layer PCB Specs the PCB substrate has a dielectric constant of 4. 500000 Kindly suggest. 10 mil is probably the thickest dielectric you should use because this will require microstrip routing with 15-20 mil width, depending on dielectric constant. Connect the amplifier output to the SMA with such a trace. I used some online calculator to calculate parameters of trace so it has 50 Ohm impedance. If we make the line width wider, we have to make the dielectric thicker to preserve the 50 Ohms, and this keeps the capacitance the same. Teflon demands even lower 1:1 ratio) The transmission line needs to be 50 ohms as it connects directly with a 50 ohm matched impedance IC, of which the leads are around 0. The Chinese prototype board houses like JLCPCB offer 0. 150. 1mm)Better to distance the RF trace away from other traces and pads, and if you can move the connector to the left 2 mm or the IC right 2mm would be better. Copper thickness (in mm) will depend on your copper weight, which will appear in standardized increments. TM. Design Note DN041 SWRA421 Page 5 of 19 5. If you were to take an ohmmeter to it you would probably. Actual board thickness 59. So, you need to calculate how much resistance a PCB trace can provide. . please help me regarding this. Email: info@multi-circuit-boards. For a pure resistor of resistance R Ohms, the impedance ZR = R Ohms. [SI-LIST] Re: Inserion loss of fr4 , 50 ohm trace . The differential 100 Ohms line has width 0. For a 433MHz line it will be between 4. To achieve 0. 7 x 10-6 ohm-cm αcopper (temperature coefficient) = 3. 9 x 10-3 ohm/ohm/C. In this stackup, the top and bottom layers are on thin dielectrics, so these layers should be used for impedance controlled signals. Why does a 4 layer PCB board significantly reduce the trace Width needed for a 50 ohm transmission line when compared to a 2 layer PCB board? Hot Network QuestionsI am designing a 50 ohm, lambda/2 microstrip line with two lumped ports each of 50 ohm in HFSS using FR4_epoxy (relative permittivity=4.