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103 Threads found on edaboard.com: Capacitor Matching
First, the output matching in LNA design should meet the stability requirements of the stage. And second, the matching network should be tuned for highest IP3 and required gain. A usual topology for output matching of a single transistor LNA, is a simple LC network (series inductor followed by a shunt capacitor). The DC (...)
You can create a bandpass filter by putting in a series inductor. Or as an alternate there is a 2-capacitor bandpass. Perhaps it's not giving away too much if I post These are merely two easy methods. By play
Apparently it's a dual variable capacitor, as used in many classical radio receivers. There seem to be four trimmer screws accessible through the PCB. In case of a superhet receiver (presume it is), the matching of both capacitors, respectively the capacitance ratio, is essential for receiver performance. What are you trying to modify?
No, the problem is that the DC generated by the diode, in you circuit cannot flows since it's blocked by the C2 capacitor. You have to connect the anode to ground using for instance an inductor having a value high enough not to affect the incoming RF.
Hi friends! I am designing a matching network between Known source impedance(50ohm) and known load Impedance(2Mega ohm). I want to know how to find the values of Inductor and capacitor. If anyones kindly share your knowledge.
Hi friends! I am designing a matching network between Known source impedance(50ohm) and known load Impedance(2Mega ohm). I want to know how to find the values of Inductor and capacitor. If anyones kindly share your knowledge.
i agree with eraste. if your line length is less then lambda/2, the characteristic impedance of the line becomes insignificant. RL of -1dB or -2dB is very bad! if you use large capacitor shunt to ground close to PA output , it will affect the S11 of output match. you are right in here! try to generate alternative matching network without cap shunt
as audioguru said, the purpose of it may vary based on where is implemented (eg. amplifier/DC bias, amplifier matching, VCO or others) what type of capacitor it is (tantalum, or ceramic) and configuration (shunt capacitor or series capacitor to ground)
Image is hardly clear but I'm assuming that they're series connected capacitors and continue. The capacitors are acting as voltage divider because the charge that goes through one of them, also goes through the other. Which means that if a certain charge is pushed into these capacitors they're going to store voltages according to their (...)
If you do a T match network for 12 to 50 ohms ( 3 components). Then you can adjust your input L to remove 5j from it. It could turn into a capacitor! Frank
Trying to understand how the matching method is applied practically. You state to use no test equipment, also the antenna impedance will be unknown in the general case. The coax segment length is determined by trial and error (best S meter indication?). How about the capacitor value?
Hello sir I am making an voltage doubler circuit at 2.45 GHz in ADS 2009. In this I have chosen 100 pF capacitor and 10kohm load resistor. now I am designing a matching circuit using microstrip transmission line in ads. can u suggest me how to find the appropriate length and width of the microstrip transmission line.
I must confess, I don't get the idea of using an OP at first sight. The loop has only stable operation conditions if VCP is buffered by a capacitor, which isn't the usual charge pump operation. Otherwise it's permanently affected by switching transients. Secondly, I don't see the need to get perfect current source matching for a charge pump. Cur
You should always decouple the TSOP Power supply using an RC circuit. Say, use a capacitor of around 22uF and a resistor of around 100E (ohms). This will prevent lot of problems. Also one more thing, the tube light with electronic choke will have light flickering may have a frequency component matching the TSOP. This mostly will happen when the
Hi. I am wondering about coupling capacitor value. What are criteria in choosing input/output coupling capacitors for LNA at 1.5GHz? They are parts of input and output matching networks. However, I think to design the input/output matching network we need to determine the values of these capacitors first.
If this capacitor is series you should add an inductor in parallel.If it's parallel, you should add an inductor in series. Depends on capacitance configuration. But I'm not sure that the input impedance becomes purely capacitive.Because SAW filters generally have an input impedance with a real part by their nature. There might be a measurement erro
In series feedback oscillator we can add varactor to tune frequency. Is it true that adding a varactor with some reverse voltage just changes reflection coefficient of matching network? As if it were designed for other frequency... So i can analyze each state without varactor and just a capacitor? For example, analyze 100 points over voltage range
That article suggests impedance matching to the audio output, which sounds like a pretty dubious proposition. I doubt that putting <4ohms on the output is healthy for the driving electronics... primar impedance of transformer with parallel capacitor (about 2uF2) form HIGH impedance state at cca 22kHz so no probl
In this situation the center tap of the balun should be connected to the ground. Either, direct connection or using a decoupling capacitor.
Hi, I am designing a CRLH unit cell with an interdigital capacitor and short circuited stub (with via to ground) in ADS momentum. I want to use this single unit cell as a matching part for my rectifier circuit ( as of now i am using a diode for simplification). Can someone help me in suggesting a way to find the impedance of the unit cell using
Edaboard says "Invalid Attachment specified." By nature, an impedance matching network with a single variable capacitor can't be adjusted for X and R (respectively phase and magnitude) matching at the same time. A common impedance matching tool is Pi low-pass filter with two varcaps, for a larger matching (...)
Q factor equation of the helical resonator most of the cases is referring to unloaded-Q, which can reach very high values. For best impedance matching, instead using just a wire connection to tap the resonator, you have to use a series trim capacitor, and adjust its capacitance in concordance of various turn ratios (perhaps 1/3 ratio should be fine
Hi How can I use interdigital capacitor for impedance matching in patch antenna.The antenna is feeding by transmission line. what's the best way for impedance maching in patch antenna?I wouldn't like to use inset feed technique.
Hi 2 all, there are another questions about class E PA :) If i want to design load/matching network for the class E PA: 1. Choose inductor and capacitor in drain of the transistor 2. Simulate load-pull contours in PSS and choose optimal impedance of load network 3. Create load network with optimal impedance 4. Create matching (...)
Yes you can keep the capacitor, but reduce value as then can matching be really easy by just adding one inductor. If you want to realize matching network inductor as a stub is ok but it takes a lot of space. If a different type of network is selected, check if capacitor also have a function as DC decoupling to avoid to (...)
See the below post: I attached a HFSS design with a lumped capacitor for one of the designs. -sv
Dear all, I am doing the matching work for differential LNA around 2GHz. To save the chip area, the input matching network is depended on the off-chip components, such as inductor and capacitor. But one thing makes me confused: since there will be discrepancies between off-chip components due to the process. These discrepancies will (...)
cks is right. And remember to include a good blocking capacitor from the top point to ground. At RF, many people forget to use several parallel capacitors to cover from DC to a maximum frequency. A good idea is to connect 10 uF, 0.1 uF and 10 nF in parallel- this makes a good RF short.
What are the metrics to be considered in designing an impedance matching network with and On-chip ESD protection ciruit? Would a capacitor suffice for the impedance matching network? Big thanks!
hi i am designing a 10 bit pipelined ADC with 1.5 bit per stage architecture. Since i am not using a sample and hold in the front end, i have to go for a charge distribution (switched capacitor) kind of comparator for path matching. The comparator i am using is shown below. I have few problems with this comparator. 1. The trip point of the compa
Hi You have a capacitor in your schematic, this is not present in the layout? Regards
If the cable is long, place a filter capacitor. A buffer amplifier won't be reasonable, I think.
In the first configuration the series capacitor to the tranfsormers (C1) is to compansate the leakage inductance of the transformers. Exact compensation is only a special case. Generally the combination of all circuit elements decides about matching. In my view, it's a simple AC network, but you have to know the parameter
L321 is used to compensate some parasitic capacitor, to have a real differential impedance. L331 is used as choke, from TX-RXswitch pin they bias the RF_N and RF_P pins, at least in TX mode. The 2 lambda/4 sections acts as phase shifting the signal by 180 deg, the additional L341, C341 make some matching impedance to 50 Ohm, plus some additional fi
Hi, I want to plot fields for a resonant microstrip. In HFSS it is terminated with a capacitor on one end and a lumped port on the other. Then I tuned and matched it in Ansoft Designer with 2 capacitors.(transferring S-Parameters from HFSS to Designer via text file). Now I want to plot the fields in HFSS as if my matching network is (...)
Hello, I have a doubt. Working at 868MHz I have a 50Ohm microstripo line, that goes to a matching network, done with 0603 elements. The problem is that the width of the transmission lines is wider than the C pad width. Which is the better way to do the layout? do, like a transition, a trapezoidal, to go down to the pad size, or do no do
50 ohm is not compelling. capacitor and inductance are used for the aim that convert output impedance to 50 ohm.
I don't see any reason to don't use shunt capacitors in a 2.4GHz antenna matching, if the SRF of the capacitor is higher than the operating frequency (which 1pF SMD definitely it is).
Is common to use high capacitor values in Power Amplifiers design, due to their low impedances that have to be compensated. Anyway, your circuit bandwidth (200MHz @ 2GHz, 10%), actually is not very broadband to implicate special issues.
Hi edaboard members! I am currently designing a Class AB Power Amplifier (in 90nm cmos process) operating at 5.8GHz. In my initial design (which consists of transistor, rf inductor choke and dc block capacitor at the output), I obtained a Power gain of 12.26dB. However, when i implemented the input matching network (circuit that matches
Im currently designing an RF PA (in the range of 750Mhz, 10W output) The output matching circuit to the antenna consist of segments of transmission line and variable capacitors (trimmers). Originally, the PA oscillates, so I try adjusting the trimmers. The thing is, I don't have a plastic screwdriver for adjusting them, so whenever I touch th
shortest is always best--gives you more bandwidth for the match. You only go longer if you need too, like you want to use a lumped capacitor in shunt instead of a lumped inductor which you do not have on hand, etc.
1)This capacitor is used to ac couple or impedance matching not for biasing. 2)They have very large frequency difference of course it is different to design 1GHZ amplifier design with compare to 1khz . 3)As it is name implies they are biasing resistors they used to stabilize the bias point of the transistor.If you want you can remove them an
Hi all. I doing an design on LNA and my LNA utilized a capacitor as DC block to isolate the DC and AC signal at the input of the LNA. The schematic is as show in the picture attached. the Cin suppose to be shorted when operating at 2.14GHz frequency but, I notice that If I put the required capacitance in the design, the noise figure of the syste
Yes, placing a small value capacitor in parallel with the big one might do the job. Is possible to need an extra inductor to compensate the broadband matching. The bad thing is that Avago gives S-parameters only down to 50MHZ, and you cannot simulate the circuit below this frequency...but only doing real measurements. By the way...sometimes th
could someone attach the following IEEE paper for me , thank you very much. A.Rossi and G. Fucili, “Nonredundant successive approximation register for A/D converters,” Electronics letters, Vol.32, No.12, 6th June 1996. James L. McCreary, “matching Properties, and Voltage and Temperature Dependence of MOS capacitors,”
replace a capacitor toward ground with a "open ended" stub and the inductor with a narrow microstrip; after that optimize the dimensions for better performances of the PA
Metal finger length affects the resistance and thus quality factor (and frequency response). One more factor is parasitic series inductance (also affecting frequency response and resonant frequency). If you are using SAR ADC, capacitors are usually built from "unit capacitors" to achieve 1:2:4:... weighting. On matching properties - you (...)
Does anyone have experience of designing a Negative capacitor circuit ? I would like some help if possible
Read it again, he's saying that solution A is not optimal. "...engineer A can look forward to a long career at SubOptimal Products, Inc." The match is between a 50+j10 ohm source and 75 ohm load. The 25ohm resistor used by engineer A has been removed. Engineer B uses the -j10 capacitor to cancel the +j10 and then an L network to comple