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81 Threads found on Varactor Design
my guess is that your varactor diode is not actually "series resonated", as is required in the first step of the paper. That tiny series inductor has to be carefully chosen so that the phase shift is on the order of 0 to 270 degrees as the voltage swings from zero to Vmax . Normally, without the series inductance, you would not get even half of
Hi everyone, I need to help with my project in CST MWS. I have to do design of an Electronically Beam Scanning Reflectarray Using Aperture-Coupled Elements as in link: but in 24 GHz. I dont know, how to do a model of varactor diode MGV-100-20 in CST.
Hi I'm designing an phase shifter and i have to use 2 varactor Diode How can i bias This phase shifter without any dc block in phase shifter. phase shifter has 2 port by the way and I'm wondering how can i bias this varactors? 119174
Hi, I?m reading materials about VCO design for reference, and in one of them there is something I can?t understand: ?Substituting this result gives Cv = 675fF. Because the varactor is in series with a 5pF AC coupling MIM capacitor, its actual value should beincreased to about 790fF.? Why exactly we should increase the value of Cv? Than
Hi, I have a project to design a VCO which i have difficulties with. Could someone please help me out? I have the following specifications: band: 1430 to 2230 MHz comparison frequency: 7.8125 kHz VCO output power: 10 mW I don't know how to find the value of the needed varactors and the s-parameters. I would be eternally grateful for t
What are the design goals? Is it supposed to oscillate at 50MHz with the varactor diode in place? I agree with others that your problem is caused by the 270uH inductor. This can be seen when we do a open-loop analysis on the circuit. There are two frequencies (one low and one high frequency) that the circuit wants to oscillate at. Replace t
LO is about 2GHz, 0dBm. Idea is to try N multiplication without using additional amplification stages. I read about varactor multipliers are good efficiency, but diffictult to design for good performance. @CW: Yup, non-linear devices (unless they are amplifiers) in an RF path at this frequency can be detrimental
Dear all Have you used the MOS varactor in the LCVCO design. There are NMOS varactor and PMOS varactor, what is the difference of them, and which type of varactor is fit for the LCVCO design. Thank you very much.
I'm trying to design a varactor stack like figure 2 (d) here: and I'm getting confused by a varactor's typical reverse leakage current rating. I've found varactors with only 20nA leakage but it seems like even that would forward bias one of the diodes. It seems like, no mat
You have to first decide on the varactor, either max or min capacity. If minimum capacity, add a bit on for stray capacity. Now work out your inductance for the maximum frequency. Repeat using figure for varactor max cap (+stray C) and if you are in luck it will be lower frequency then required. if not you need a better varactor. remember, (...)
I am designing LC VCO using PMOS varactor in ADS. In typical LC VCO, L and C values are selected according to the formula f=1/√LC. How to find the PMOS varactor width values?. Also oscillation frequency versus control voltage is plotted for this VCO. very small variation in the oscillation frequency only obtained. Anybody (...)
It depends on the varactor curve, and the LC formula - freq will vary proportional to sqrt(1/C), so it's non-linear.
Classic design.. Consider 50% less solder needed next time but heavy parts may need PU adhesive on comp side. Consider BB187 more readily avail. varactor diode. with 11:1 ratio and good matching.
A tuned multiplier will not increase the jitter. A PLL type approach will. Yes, if we ignore a small noise induced jitter contribution of the varactor diode, or whatever is used as frequency multiplier. The succeeding comparator converting the 240 MHz sine into the required square wave will show some more jitter, but 1-2 ps seems re
The Armstrong FM modulator is the choice for you request, but is much complicated than using a simple varactor part of the resonant circuit. See the original block diagram and schematic, from Armstrong patent file in 1936.
The shape in the picture is not a branch line coupler. To bias the varactors, instead using an inductor connected to the middle of the coupler, try using two resistors (~100k)
Hai to all, i am struggling to design PMOS varactor at 5.2ghz.Please help me the design procedure in ADS Agilent. Thanks.
Hai, I am new to the design of phase shifter using varactor diode. Can some one tell me what are the factor that i should consider for the design .Pls refer some sites and ideas. Thanks, Shopi.
Hai, I have planed to design a bias tee for measuring the capacitance of varactor diode. the frequency of operation is 300k to 1.5G hz only. I cannot use ordinary RF inductor bcoz it has parasitic capacitance and results in SRF. I have two doubts 1)Should i only be using a microstripline for the bias tee design? 2) I can (...)
Hai, I need to design a bias Tee for measuring the capacitance of varactor diode using VNA. To bias the varactor diode i need measure the capacitance i use S11 value from the VNA. So to separate the RF and DC i need a bias tee arrangment. So pls suggest some design techniques/link/books for (...)