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39 Threads found on edaboard.com: Surface Currents
I'm a designer having a discussion with a coworker who's background is PCB manufacturing. On our PCB fab drawings we call out IPC-6018 with an ENIG finish and I questioned him on why we aren't using electrodeposited Ni/Gold. He replied that we only use SMT chips (no wire-bonding) and the thicker gold would cause Gol
What is the concept behind surface currents of a microstripe patch antenna? what should be its range for good performance of a patch antenna? Thanx in advance
surface current density is A/m
Since FR4 is epoxy is a thermal insulator or rather the conductance is <<10% of copper, you are basically only using 1 side of copper and as I recall forced air can improve this up to 5x with 1m/s air velocity over the surface depending on geometry of obstructions, lack of eddy currents etc. Vias will improve this but also have low conductance so h
what does power loss density and surface currents show?
Have you studied the currents on the outside surface of your horn antenna, particularly around the mouth of the horn? It sounds like you might have high currents that are leaking back onto the outer surface of your antenna, and these currents might be creating the radiation. I think there is a Field (...)
look up the term "split block" waveguide. If you want to make a piece of waveguide in two halves, you split it along the centerline. You do not make most of the waveguide in one piece of metal, and then bolt on a flat cover. That is because RF currents are at a MAXIMUM where that cover would attach, and if there is any surface roughness or warpi
An enclosed chassis doesn't radiate (unless you manage to inject differential surface currents). Cables running out from the chassis may radiate if not filtered suffciently against the chassis ground or provided with a large common impedance. Grounding the chassis does not necessarily reduce radiated or conducted interferences, the effect depends o
I came across a batch of faulty transformers at work, they were 230 V to 50V @10A, they worked but always ran really hot , say 70 degs C on their surface. The problem was that the long bolts (4 off) that ran through the stack of laminations at each corner did not have insulating bushes fitted even if they actually had sleeving down the threads, the
Less surface current, higher the gain. Also to get better microstrip antenna radiation (higher gain) is to have less currents that propagates into the substrate. The radiation performance (and gain) of microstrip antennas is degraded by the diffraction of surface waves at the edge of the substrate.
The recombining carriers are responsible for the "nonideal base current" and the rolloff of hFE at lower collector (base) currents. You can get bulk and surface recombination. The latter is why lateral devices svck so badly.
I have designed two arm archimedean spiral antenna in CST i got acceptable results but i want to get analytical results such as gain, axial ratio, radiation pattern, return loss and surface currents by using matlab so can any one help me to give me or guide me how to get the matlab code of this antenna.. your help is highly appreciated. thanks
In FEM, you need to discretize the analysis volume, including the air around your device, and have to define the boundary conditions at the sides of that analysis volume. In MoM, you solve for the currents on the conductors (surface meshing) and there is no need to discretize the volume around the device. The boundary conditions are
Hiya suraya, I'm not sure I know what you mean by "probe" the antenna...? If you want to excite/add an s-parameter port to the structure, you can use a 'discrete port' at a given set of (x,y,z) coordinates. Alternatively, if you want to visualise the fields/surface currents within the structure, add the appropriate "field monitor" found under th
you seem to be confusing 2 concepts. If you have a symmetrical transmission line cross-section, such as coaxial cable, then you skin depth understanding applies. The RF currents on the center conductor, for instance, are mostly on the surface, with just a small portion going deeper. So if you are fabrcating your own coaxial line, you can use e
If the board has been throughly cleaned, you don't need to fear surface currents at 90% humidity. "Dominating surface currents" would be a fatal condition in my opinion, for high performance instruments a variation of 1% (< 1 Gohm surface resistance) or even less would be considered critical. The problem (...)
I recall having to instantiate a trivial resistor to "force the veriloga currents / voltages to the surface". More of a workaround than a solution.
Hi, I have export the currents density in specially surface from cst mws to a txt file. The exported file contains Re(Jx), Re(Jy), Re(Jz), Im(Jx), Im(Jy) and Im(Jz). How can i plot the instantaneous distribution of inplane component of J by matlab or Golden Surfer? I have tried to plot the (Re(Jx), Re(Jy)) and (abs(Jx), abs(Jy)), both results
TIP122 is a 8A device that can work with up to 65W with a heat sink, with an smd transistor you will not be able to handle big currents because of the low cooling surface and there will not be an option for heat sink either. Do you want to use it in a low power application? Alex
Look up "High Impedance surface" in the literature...same thing but a more common name. There is a ton of stuff to get you going...think Sievenpiper ;) Any Integral Equation software is going to be limiting as they do not handle dielectrics well...I suggest HFSS as there is a full writeup on this topic from determining Block diagrams to dispersio
Dear all, I am trying to design a microstrip antenna. I want to view surface current on the patch. Please anyone help me in detail how i can view the surface patch current clearly. Please halp me. It's urgent. Mailing me is also appreciated. Thank you all
Hello, Yes, you can completely see & visualize & even annimate the currents on Microstrip Antennas surface such as GND & top Patch plane using Sonnet em Suite Software... Go through the user Guides of Sonnet Lite you will see lot of references on this topic.. ---manju---
GIDL: Gate Induced Drain Leakage. GIDL currents arises in the high electric field under the gate/drain overlap region. GIDL occurs at a low gate voltage Vg and high drain Voltage Vd and generates carriers into the substrate and drain from surface traps. (taken from: Kaushik Roy :"Low Power CMOS VLSI Circuit Design")
Means that the maximum applied voltage is not to be calculated with Ohm law but must be a maximum that is written on the data sheet Working with a voltage across the resistor that is above the maximum allowed will bring to arcing and surface currents that will destroy the resistor and probably also the electronics around Also another question
GIDL currents arises in the high electric field under the gate/drain overlap region. GIDL occurs at a low Vg and high Vd bias and generates carriers into the substrate and drain from surface traps or badn-to-band tunneling, (taken from: Kaushik Roy :"Low Power CMOS VLSI Circuit Design")
In electrical engineering ground is equipotential surface.
Hi! I tried to simulate a patch antenna using FDTD. This patch is fed by a microstrip line. In general it is working fine. but there is one unwanted effect: the currents flowing along the resonant length on the patch are not of the same size along the width of the patch. there is a strong and sudden increase towards the edges. the width of the
KVL states that the sum of the elements voltage in a closed loop is zero but KCL says that for a closed surface the algebraic sum of the currents are zero.
Hi! if I plot the current on a ground plane I get a 3D plot, with animation and so on. I want to export this plot...I mean I need the file text of this current surface. for the field I've seen that this is possible, but how can I do it for currents??? thanks.
Hi, Problem 1 If you have a common ground interferance might become a problem, however over short distances this should not be the case. Optoisolators cannot translate 5V to 24V it only protects the 5V circuit from the 24V one. Problem 2 Depends on what currents you require on the 5V side, for low currents small surface mount (...)
When I try to simulate surface currents in CST it says that "current monitor only considers electric conductivity and will be ignored for dispersive material behaviour". How can I fix this? I am using PEC for the SMA connector and Copper for the microstrip line and ground plane. What's wrong????
Can anybody post examples of microstrip structures simulations in Momentum? Such as couplers, mittered bends, and other structures where you can see the surface currents... I would be grateful for any stuff like that.
Is it possible to hide the X component of the surface currents on a microstrip line, such that only the Y component remains visible? Being Y the axis perpendicular to the direction of propagation of the currents, and contained in the microstrip plane. I need it in order to see the quasi-TEM nature of microstrip. Thx in advance.
for perfect electric conductor, the current would flow/concentrate on the surface.
i have found some papers on how to computate the elements of mom matrix elements fast which are used to analyze the microstrip antennas.But all of them do not consider the attachment currents at the junction of probe and patch, and not include the probe surface currents either. if i take these currents into account, are (...)
if i have get the currents distribution of the microstrip patch surface,how to calculate the pattern of the microstrip antenna? i have read some books,but all the formulars to calculate pattern of the microstrip antenna must be used in spectral domain,is there formular in space domain? THX
They were originally used in analog circuits made on PC boards. They surround an area where surface currents are a potential problem. By putting a potential on the ring that is equal to the potential of the circuit portion inside there is a zero potential difference across the PC material and so no leakage currents flow across the PC (...)
The proximity effect causes the current to stay even closer to the surface of the wire than the AC frequency would cause. Another view is that the current in one wire induces eddy currents in adjacent wires. Sum total is that more loss (heat) is generated in the copper wires. Two solutions sometimes used are stranded wire or using several smal
Make sure you observe the DC current rating of the inductor. Alot of these small surface mount inductors and others have hardly any inductace when large DC currents are being passed through them. Decoupling inductor or tuning inductor. Q may be of importance, just a reminder...........