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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
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
Hello, Is there anybody who already designed a PA that should drive a SAW filter ? Should we provide a particular output impedance to the SAW to reduce VSWR ? Lots of design papers says that you should transform the load to the optimum load to have best efficiency. Suppose I have a 50Ohm SAW filter that is terminated with a 50 Ohms impedanc
This post is about impedance matching of Rf power transistor, these power transistor usually have low input/output impedance like z= 2.1 - j3.9, The first question is that what is the usual practice for matching this low transistor impedance to standard 50 ohm, Is single stub matching is the only preferred choice for complex to real (...)
Zx should be 50 ohms. This is the reason using of the impedance transformation Network.
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
Dear All,,, I have a question regarding the basics of transmission lines... If there is an RF source with rms voltage of (Vg) and an internal resistance (Rs) connected to a quarter wave transmission line terminated by an open circuit. Now since the RF source would see a short circuit at its terminals because of the impedance transformation o
Hello I consider the attached image which is the first stages of a regenerative QRP receiver. The amplifier comes from another project and output impedange is 50 ohm. The detector assumes an imput impedance of 50 ohm I think as well. Since I would like to combine these circuits, I would like to migrate the output transformer of the rf amplifier w
Hello, I have recently designed the PCB for a prototype UHF Receiver. The receiver operates from 450 - 458MHz. Anyway I requested 1 board from the PCB manufacturer and they asked me if I wanted impedance control. I have already designed for an impedance of 50 ohms. At these frequencies can I expect much variation in the impedance of my (...)
It is the delay, that causes impedance transformation. Use any cable impedance as long as its length is correct relative its velocity factor, which can differ between different types of coaxial cables.
Yes, there can be different impedance (or return loss) at antenna connector and the other side of the feeding transmission line. This is the reason that have to keep tracking the impedances all over the transmission path. Usually the RFIC manufacturers provides the impedance (S parameters) at particular pins of the IC package, and not behind (...)
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,
I need information on toroids for 1-40MHz applications mainly related to impedance transformation. Where can I find the information on general toroids, windings, ... etc madhukar
BalUn is a device to transfer the energy from Balanced-to-Unbalanced (or vice-versa) configuration. Differential amplifiers , dipol antennas , mostly mixers etc use Balun. For instance 50 Balanced input impedance can be converted 50 single ended Unbalanced input/output. Additional to , it may serve a impedance matching function but it's not
There are lots of companies that have surface mount PCB transformer. You can choose the impedance transformation ratio and the operating band.
There are all sorts of passive networks that can change one impedance into another. The audio transformer is one example. Pi and T LC networks can also change the phase angle. Matching is a special case of impedance transformation where the new impedance is what you want. That is, you design the network to get the (...)
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
For infinite gnd and substrate 1. You need to change the connector dia according to requirement. 2. Change feed impedance to 100 in Modua For finite gnd and substrate just draw the entire feed including inner and outer conductor of the coaxial probe. Hi to all, I am presently engaged in design of folded P.A.T.C
Hi Iam having problems with differential Lna simulation in spectre. I have designed a matching network that would step down the impedance to a low level . After that i have used an ideal balun from the rf lib and tried to simulate it. I also tried with a VCVS.Neither of these seem to work. My S21 is a straight line . BTW the impedance tran
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 (...)
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,
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
impedance transformation is must for patch antenna array for proper Powerdivision among the antenna array elements. Feednetwork behaves like Wilkinson powerdivider. U can analyze this from the example given in IE3D manual.
Hi everybody I need to transform a negative resistance of -5980 Ohms into a smaller value as it has to be generate by a transistor (Mesfet) by using a characteristic impedance of 90 Ohms for example. I'm using a quarter wave transformer with the equation: Zin=Zo^2/Rl. I'm getting only an imaginary part but my supervisor told me I should only obt
try using a impedance transformation circuit(i.e. L-match Π-match etc) to transform the 22 ohm to 2.2k.....
You have to give more details: - what is the output impedance of the generator? 50 ohm? - what is the input impedance of the matching box? 50 ohm?
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
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 (...)
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.
Balun or impedance transformer?? Balun!
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
Hey, I have to design a power amplifier in 130 nm technology witht he following specs Power Output: > 23dBm (at PA output) Total Power Consumption: < 0.5W @ 16dBm CW output power RF Input Signal @ 2.45GHz : 1Vp-p sinusoid if single ended -- differential or single ended 1.414Vp-p if differential Input Source impedance 50 
Change port 2 and 3 to 25 ohm differentially. Or use configurations for impedance transformation.
I'm not quite sure but I think that two twisted pairs would be winded on the core. You use twisted pairs to get a transmission line transformer for higher frequency operation. This is equivalent to reducing the parasitic capacitance. I assume the unconnected winding is one of both threads of the primary that is not used because a 4:1 impedance tran
Hi, I design a two stage UHF amplifier, 2Watts. I have a problem two achieve a wideband interstage matchig. The optimum output impedance of the first stage is R=U^2/2P => R=100 ohm while the optimum input impedance of the second stage is only 4 ohm. With such a large impedance ratio it is very difficult to achieve wideband matching. I (...)
Both parallel capacitor pairs have to be tuned while the series capacitors are setting the impedance transformation ratio. 68 pF surely isn't correct, it's 2 x 68 pF each in the NXP application note. In my opinion, a 50 mm coil should rather have 4 than 2 turns, and it's not suited for distances above 50 or maximal 70 mm anyway, even if perfectl
I am confused by this post. The reactive power splitters I have used have S21 = S31. And they work fine as power combiners too. Working as a splitter, a 50 ohm source comes up to a T junction. At that T junction, looking one way, it sees 100 ohms resistive. Looking the other way it sees 100 ohms resistive. When the two paths are combined a
I agree, that a LC series or parallel filter at an impedance level of e.g. 50 ohm involves unhandy L and C values. Usually bandfilters are build as a parallel circuit with high characteristic impedance (kohm range) and impedance transformation to the signal path.
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, (...)
I checked, that the site is working. Here's the direct tool's link: But the tool is for inductance calculation only, not for design of resonant circuits or filters. I guess, you intend a matching circuit like the below Philips/NXP application? Viewn from the coil, the parallel and series c
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
Why don't you make a s-paameters simulation instead of AC to get the reflection coefficient and then impedances ?? If you know the reflection compare to characteristic impedance, after that you can get the real impedance.
generating the current required for the effective reception of the signals I guess you are talking about driving the reader coil? It can be expected as an inductive impedance, and surely not a "resistive load of 19 0hm" as annotated in the circuit diagram. But the circuit also misses any means for RF modulation. It would be better
the linecalc only calculate the width of feed line at one operating frequency,doesnt it? The change in the line impedance over frequency is very small.
In general, the bandwidth is reduced by increased impedance ratios and increased with more LC elements in the network.
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). (...)
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 (...)
I think these are 1:1 balun so output impedance and input impedance is same..50Ohm..