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55 Threads found on edaboard.com: Impedance Transformation
Hello guys, I am currently making a design including a GSM module which has a 50 ohm impedance output for the antenna. However I am interested in using a dipole (73 Ohm img 43Ohm) antenna with this module. I have been searching around for either a dedicated , or discrete balun that can handle this transformation, with no luck. Does anybody h
Most of the balun types i have come across are not suitable for my design i.e a UHF dipole antenna for a nanosatellite. Surface mount transformer baluns have insertion loss and reflection which is normally acceptable but due to lack of power on the satellite we cant afford the loss. but these baluns are all wideband which is why they show bad perfo
Because you mentioned "step up to 50 ohms", means the PA output impedance is lower, and usually this kind of transformers use 25 ohms coax cables.
Could I use this kind of impedance transformer to do this? Yes. In fact there are no alternatives to a transformer, preferably a transmission line transformer.
i need to design a Coaxial impedance transformation which as a part of a complex antenna ,but i am not sure about the feed in feko. i use the waveports,then meshed it has wrong in the port.could anybody can give me some suggestion.plz
i would not do it that way. you show an elliptical lowpass filter. If you make use an open circuited stub to approximate the L-C shunt resonator, then you simply set the electrical length of the stub to be quarterwave where the L-C element resonated in frequency. You choose the impedance of the stub transmission line to approximate the reacta
By "hole" do you mean a via between your signal trace and ground? If yes, the main requirements are that the hole/pad diameter is less than lambda/4 of your design frequency. This hole condition is required for it to not radiate (losses) and the length of the via should be less than lambda/4 in order to avoid an impedance transformation at the shor
hi, i want to design an expeonential tapered microstrip line for impedance transformation from 50 to 100 ohms.now i caluclate w(width of M/S) using tline calcuator and w2=5w.now for exponent factor of m/s line i used a=1/L* ln(z0/ZL) but i dont know how to find exponent factor for ground???that is also tapered in such a way that its widt and M/S l
So you want to impedance match a radio with antenna for maximum efficiency and have a transformer somewhere along the line. impedance matching can be done on either or both sides of transformer. It is only a question of what is the most practical alternative. Assume components have been added resulting in conjugate match between antenna and transfo
See this thread about TI CC2520, a 2.4 GHz radio: Is it a related type of problem? According to that link should impedance matching at least for first harmonic be high impedance matched (reflective) as it affect TX efficiency. My practical tests with CC2520 shows that also. It can be a dif
Real or imaginary part of what? impedance?
depends also on frequency -> substrate loss or coupling or changed impedance transformation if taken into account.
Your patch itself very likely doens't show a real impedance. Your resonance is due to a combination of the wierd impedance of the patch at 4.55 GHz and the impedance transformation due to the quarter wave transformer. Of course at 4.55 GHz your quarter wave transformer no longer functions as a quarter wave transformer. (...)
What does impedance transformation mean with regards to antenna? For most folk, this means to alter the driving point impedance by adding some sort of matching scheme. This is usually a network of matching components/devices , between the the energy source and the antenna driven point. Stretching the meaning a little, it might
Hi all, What does impedance transformation mean with regards to antenna? Is this transforming the input impedance(Z11) of an antenna to the desired value? Can an L section using lumped components manipulate the resonant frequency of an antenna? Regards, Vineeth
Hi! I`ll work with for very first time. I want to use it for current measurement through current transformer. I have current transformer with impedance of 50 omhs and transformation ratio 50A to 0.05A on the secondary coil. Can you give m
Sure - you can use whatever lengths you like (provided the circuit parasitics don't swamp whatever effect you're trying to achieve with lengths of transmission line). There's nothing magical, prescribed or fixed about your choice of line lengths :) ANY length of transmission line will perform an impedance transformation (provided the load impedanc
All conductors are transmission lines. When they are very short compared to a wavelength or compared to a pulse rise time they can be accurately approximated as an ordinary connection without considering the reflections and impedance transformation effects.
So even if the matching network is lossless how can i say that no power is lost in the impedance transformation network as soon as a portion of it will be reflected back? The idea is that reflected signals cancel. Or in other words, the load impedance Zl should be transformed by the quarted wavelength line,
Hi, I have a question about an output combiner design. I have designed a 4 ways output combiner which provides transformation of impedance (50 ohms) to a desired impedance for the transistors. I have simulated very good output power level and the matching network is very low loss but when I perform a small signal simulation I am (...)
Tapped inductor circuit is really an autotransformer and as such has the proprieties of impedance transformation. This circuit can be used to increase the effective source or load impedance in order to improve the loaded Q of a circuit. In other words, the Q of a LC circuit will decrease when we connect a transistor to it, this is because (...)
for crystal model ( C , L, Rs ) in series L = 3.5m H (offchip xtal component) Rp (transform) = (wL)^2/Rs this is huge value for w =120M Hz, Rs=50 ohm--> Rp=1.4*10^11 ohm so i need a circuit where the crystal should see w very large Z to prevent decreasing the Q heavily or what ? can any one help me in this
Power amps have a fairly high input line level (~1V?) and an impedance that is mismatched to sources like mics and guitar pickup coils. Preamps may perform not only gain, but impedance transformation as well; they may include shaping of frequency response (like a RIAA phono preamp). The noise qualities may receive more attention (...)
Hi, I am confused about the format of input and output impedance of RF transistors. For some devices impedance are given in series form and in parallel form for other devices. Some data sheets do not mention. Why series to parallel or parallel to series transformation is required. I am using pd85004 ldmos for amplifier. When its model (...)
I think these are 1:1 balun so output impedance and input impedance is same..50Ohm..
It goes like this: C251, C251 are DC block L251 is used to compensate some internal cap, to have a real differential impedance C252, L252, C262, L261 is the real balun; it gives a 90 deg phase shift on each branch (with opposite sign) plus a certain impedance transformation. C253, C254, C255 probably a match to 50 Ohm plus some filtering (...)
In my opinion, the function of the "red" quarter wave transformer is impedance transformation. C is required to block the DC. If the Z0 of the "red" line is above the reference impedance, and less then quarter wave length, the combination of "black" and "red"+C sections may be part of a 2nd order band pass filter (with good return loss). (...)
In fact this is not balun configuration, because pin 2 of SA612 is AC connected to the ground (reactance of 100nF looks almost as a short at RF frequency). This is a capacitive tap impedance matching, which is using the formula as in the attached picture (this is valid only if Rs < If
Hi maria, you can transform pi into tee by impedance/admittance transformation. Regards Z
In general, the bandwidth is reduced by increased impedance ratios and increased with more LC elements in the network.
what will be the impact on RF performance? It all depends on the length of the line relative to the wavelength. If the line is 1/20 wavelength or shorter (effective wavelength including substrate epsilon), then the impedance transformation due to the wrong Z0 can be neglected. If your line is longer than that, you
Zx should be 50 ohms. This is the reason using of the impedance transformation Network.
Hi, all, Let's consider a 50 ohm to 200 ohm impedance transformation SAW filter, and it has the insertion loss of 1dB. If it is inserted between a 50 ohm antenna and a 200 ohm LNA, will it help with the chain noise figure, or the noise figure of SAW+LNA will be better than LNA alone (refer to 50 ohm)? Please let me know your calculation, if y
This is the all idea of tapped line, to provide an impedance transformation. So you have to tune the filter design (length, spacing, width, etc, of the resonators) in the way that at the tapped point the impedance is nearly 50 ohms, meeting in the same time all the other parameters of the filter, insertion loss, rejection, bandwidth, (...)
Hi Your impedance network "takes" care of the transformation of the voltage and currents. The way we insert the voltage at either drain/collector through fx. inductor. The voltage swing at the drain is larger than your supply voltage: Vcc+Vd. This can happen because of your LC network on the output, which transforms the voltage and currents.
Change port 2 and 3 to 25 ohm differentially. Or use configurations for impedance transformation.
The DC feed is basically used to feed with DC the balanced inputs (or outputs) and should have minimal effect on the balun performance. Of course, those feeds/teeminals can play a vital role if they are used in the impedance transformation, but 50:50 Ohm conversion will actually require AC gnd for those nodes... --padpan
@FvM ... what diff amplifiers do you use and where do you get them? @eecs4ever ... datasheet of you ADC usually suggest a wideband transformer, if not, choose one from Mini Circuits. Watch out for the correct impedance transformation and termination.
Hi, I have the following broadband power amplifier 400M-1G that I need to reverse-engineer sort of and having problems calculating the impedance match. I do understand that the coaxial cable transformers (Zo=10ohms) sort out the basic transformation ratio but still the transistor (LB401) has got capacitive input and inductive output. That is wher
Why does the impedance at the patch input is purely real ? As we all know the patch antenna input impedance stems from the transformation of the same impedance from one end of the patch to the other. As balanis says the imaginary part of the addmitance in one side cancels with the imaginary part of the other side when (...)
Why does the impedance at the patch input is purely real ? As we all know the patch antenna input impedance stems from the transformation of the same impedance from one end of the patch to the other. As balanis says the imaginary part of the addmitance in one side cancels with the imaginary part of the other side when (...)
i tel u y , coz in ur schematic , u used both terminations are 50 ohms u need to change term 2 to the impedance of the load , and things will work khouly
try using a impedance transformation circuit(i.e. L-match Π-match etc) to transform the 22 ohm to 2.2k.....
In CMOS PA design one trick that could be done is to use multistage output L networks, to decrease the insertion loss and improving indirectly the efficiency. Multistage L match may have lower insertion loss if the reactive component or components have low Q, even though the impedance transformation ratio is not high. The loaded Q of each stage s
Hi, there are three thechniques to design a broadband matching network analytical real frequency transformation Q They are far complicated to explain them in the forum like this, please refer to the literature: George L. Matthaei, Leo Young, E. M. T. Jones ? Microwave Filters, impedance Matching and Coupling Structures, Artech House,
Hi, I feed to feed a Patch Antenna (Edge Fed with MStrip Line) where the Input impedance at the edge of my antenna varies from rapidly over my band of interest. Note: I have resonance at the centre freq but below and above that its comples impedance. Any suggestion on what kind of matching/transformation circuit (MStrip) can be used to (...)
As said above transformer is not an amplifier. But the propertie of voltage transformation can be used as step-up booster where secondary voltage is higher than primary voltage. Secondary load impedance must be higher than prinary one or it should be highohmic.
It is also the very simplest divider. It has large bandwidth if compared to other kinds (gysel or rat race), and the bandwidth can also be broaded inserting more λ/4 sections. In fact just one λ/4 section could make the impedance transformation, but if the "jump" is big (e.g. in a 10 ports divider/combiner you have to realize an i
Dear all, I have a 2-wire dual mode speaker with the differential impeance 32 ohm, and it will driving by a audio amplifier with the output differential impedance 8 ohm. My question is that how can i do matching between them to maximize the efficiency. Thx a lot, Best rgds.
What is your transformer windings ratio. Power line is low impedance load and you should have step down transformation to it. If transformation ratio is low you would short circuit your output circuit. It is impedance matching case. What happens if you connect only primary end of transformer, does the voltage stil drops. If (...)