29 Threads found on edaboard.com: Rf Power Amplifier Stability
it is easy to check the stability of the power amplifier,follow the following steps:
1) link the signal source and the power amplifier and the attenuator with the spectrum analyzer.
2) set the power amplifier analyzer full span
3) then turn on your (...)
RF, Microwave, Antennas and Optics :: 06.03.2005 01:58 :: springf2000 :: Replies: 4 :: Views: 2078
Which kind of substrate the designers use as PCB in RF power amplifier circuit?
I give a picture below
RF, Microwave, Antennas and Optics :: 04.03.2008 03:07 :: jayce3390 :: Replies: 4 :: Views: 1257
I am designing a 30W Rf hybrid microstrip power amplifier in S frequency band.
I encounter stability problem that's why I need to implement serie resistor on the RF path to improve the power amplifier stability.
I am looking for a 10-20 ohms chip resistor able to support 1 to (...)
RF, Microwave, Antennas and Optics :: 07.07.2008 08:30 :: jayce3390 :: Replies: 16 :: Views: 908
Try to measure the DC drop exactly on the collector/drain of the final stage at maximum output power. Also check if there is no DC voltage drop at full power through the ground near the final stage.
You didn’t mention the output power, but some low-Q capacitors starts to behave poorly at high RF power, and this (...)
RF, Microwave, Antennas and Optics :: 26.08.2009 04:04 :: vfone :: Replies: 6 :: Views: 2133
I made stability simulation and it's ok. It seems stable at every input output impedances.
Here is additional information. The amplifier is LDMOS MRF6S27015GNR1. I commonly used the test circuit of the device. I transformed the impedances compatible to my dielectric substance fr4 , 1.6mm thickness where the test circuit was built in taconic rf-
Analog IC Design and Layout :: 15.03.2010 10:43 :: xeratule :: Replies: 3 :: Views: 1610
Dear microwave specialists,
I am designing an RF power amplifier operating at C band. I am simulating some gain (spikes) at low frequencies up to 4 GHz. The transistor itself shows obviously a very high gain at low frequency and it appears difficult to me to lower this gain with the matching network. The power amplifier (...)
RF, Microwave, Antennas and Optics :: 24.08.2012 14:25 :: jayce3390 :: Replies: 5 :: Views: 431
I'm drawing the layout for a rf power amplifier and I would like to know if there are other ways of optimizing the transistor (other than finger) to reduce the parasitics of the transistor?
What are the techniques used normally for drawing transistor layout in rf power amplifier?
Analog IC Design and Layout :: 22.12.2005 20:27 :: LaughingMAN :: Replies: 6 :: Views: 1597
I am assuming that by intermittance you meant that you have intermittent output power cutouts.
This type of intermittence might be caused by excessive current and/or voltage across the RF capacitors in the RF circuit in itslf and/or in the RF by-pass network. If it is the case the capacitor's ceramic will be slowly cooked what, over the time, w
RF, Microwave, Antennas and Optics :: 02.03.2009 17:20 :: nandopg :: Replies: 13 :: Views: 3533
i need some material on multistage amplifier stability analysis. Is there any paper or guide in analyzing the stability for multistage rf power amp.
Electromagnetic Design and Simulation :: 10.02.2010 12:36 :: danesh :: Replies: 0 :: Views: 846
The power amplifier gain is part of the RF System analysis of the entire transmitter chain.
The gain and loss of each transmitter stage should be distributed from the modulator up to the antenna.
The gain of the power amplifier is limited by different factors, as stability, number of internal stages, (...)
RF, Microwave, Antennas and Optics :: 28.04.2010 01:09 :: vfone :: Replies: 2 :: Views: 552
I have the problem when design RF 50W & 200Mhz power amplifier, because i knew some opamp can work at high frequency so i wonder i can use opamp (now i use AD8024) for power amplifier or using transistors (an9024), could anyone help me solve that problem?
RF, Microwave, Antennas and Optics :: 14.03.2012 14:19 :: vodanhtieutot :: Replies: 8 :: Views: 759
i have Input and output impedance for high power transistor. (zin =real +img)
how can i know if it is stabillity at this point.
Possibly not, you need more information as S21 and S12 (gain and loss in each direction) above your know S11 and S21 (Zin, Zout) and in wide ran
RF, Microwave, Antennas and Optics :: 18.09.2005 16:11 :: xxargs :: Replies: 2 :: Views: 572
I'm trying to design RF transciever for OFDM (Wimax, in particular) system. Is there any good reference I can study?
Also, the idea of "Digital RF Processing (DRP)" has been proposed recently (see e.g. ). Do you have any suggestion if I would like to design the OFDM/Wimax transcei
RF, Microwave, Antennas and Optics :: 20.02.2006 00:53 :: fatboy9345 :: Replies: 17 :: Views: 2381
I need to build a project for 10MHz oscillator (Sine Wave) and output amplifier @ about 30 to 40 Volts and 30 Watts. Can any one help me for the schematic or some site for reference guidelines.
Will be greatful for.
RF, Microwave, Antennas and Optics :: 03.11.2006 09:33 :: Raza :: Replies: 1 :: Views: 648
hi all, please assist me, i want design rf amp following this spec;
I/O r.loss <-10
class = ?
matching = stub
board = FR4 microstrip
software = ADS
im stuck now, where should i start?
RF, Microwave, Antennas and Optics :: 17.04.2008 03:17 :: cyconx12 :: Replies: 8 :: Views: 947
Thank you for reply~!
I use cadence RF Spectre, and PA is class AB type.
I checked bias point, and linearity.
For large signal, should I check others except K-factor?
RF, Microwave, Antennas and Optics :: 28.08.2008 19:00 :: Henry-cool :: Replies: 5 :: Views: 2508
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 (...)
RF, Microwave, Antennas and Optics :: 09.04.2009 15:14 :: mehul87 :: Replies: 0 :: Views: 621
I guess when we using spectometer, we can just check the spectrum when device is powered on and powered off, then find out if oscillation is present.
As i have no decent signal analyzer, i use another approach:
I make a simple probe with schottky diode, one pin grounded and other pin connected to OpAmp. Next, i put
RF, Microwave, Antennas and Optics :: 17.08.2013 03:35 :: jiripolivka :: Replies: 1 :: Views: 192
there are two kinds of unstability:(1)the rf unstability(2)the feed DC power unstability:
the resistor in the drain only conquer the feed DC unstability,but not RF unstability,try to add a resistor in the rf chain
RF, Microwave, Antennas and Optics :: 10.10.2004 06:58 :: springf2000 :: Replies: 3 :: Views: 642
Just wanted to ask if it's possible to stabilize an amplifier by placing a shunt resistor at the output of the amplifier. I notice that all the RF power will be shunted to ground if I place the resistor there. Adding a series inductor choke to the resistor didn't help at all, the S21 is still negligible. So is it possible?
RF, Microwave, Antennas and Optics :: 12.07.2005 09:28 :: countmybones :: Replies: 4 :: Views: 576
If it's a High power Amp you should get the Impedance vs. Freq from the
IC maker. Conjugate Match your circuit to the Impedance and you will get better
performance. The S-Parameters are more for small signals and it's hard to
make models to simulate AMP's as they reach higher powers.
RF, Microwave, Antennas and Optics :: 09.02.2009 16:34 :: Element_115 :: Replies: 13 :: Views: 7335
Hi, I have a simple question about the input matching of RF amplifier.
If the amplifier has medium gain (about 15 dB), but bad input matching (about -3 dB), what is the impact of it to the whole RF system?
Since about half of the power is reflected back to the input path, does the bad input matching increase the RF coupling, and (...)
RF, Microwave, Antennas and Optics :: 29.01.2010 01:09 :: winglj :: Replies: 1 :: Views: 562
i'm trying to match the input and the output stage of a VHF pre-amplifier using simulation in ADS. When i match the output stage everything is ok but when i try to match the input, the output is no longer matched, the gain drops and the stability factor also drops below unity. I guess there is a interrelation between the input and output ma
RF, Microwave, Antennas and Optics :: 19.09.2010 12:23 :: Draytek :: Replies: 6 :: Views: 1149
MatLAB is not a RF simulator.If you're keen to build up a real LNA, use professional simulators such as ADS, MWOffice etc.
RF, Microwave, Antennas and Optics :: 23.01.2011 14:23 :: BigBoss :: Replies: 3 :: Views: 759
An "RF driver" is just an amplifier. In order to reach the desired output power for the system, more than one gain stage is probably required. The power MOSFET amp likely doesn't have sufficient gain, alone.
Agreed, and sometimes you may have a pre-driver stage in there too.
It is common to spread gain out over
RF, Microwave, Antennas and Optics :: 15.04.2012 04:05 :: davenn :: Replies: 6 :: Views: 418
First thing to do is increase C2 to 1000uF. If the power supply does not have a very low source impedance, it might help to increase C3 as well.
If there is any problem with High frequency (RF) stability, it may help to connect a small capacitor (47pF to 100pF) between the collector and base of T1.
C1 can be reduced to
Analog Circuit Design :: 10.06.2013 08:38 :: neazoi :: Replies: 4 :: Views: 272
I am designing PWM based integrated DC-DC converter operating at 300MHz clock frequency. I need to do the stability analysis of whole circuit inorder to check whether the whole feeback system is stable or not. What kind of simulations i should do for that in cadence spectre RF?. What kind of error amplifier will be suitable for this kind of
Analog IC Design and Layout :: 04.08.2013 12:13 :: viperpaki007 :: Replies: 6 :: Views: 566
Which tool are you using in terms of simulating your RF design?
If you are using ADS, there's an optimization option/tool avail where you can tell the simulator that you would like to optimize the gain to such and such, putting low constraint on the other factors like noise factor.
Electronic Elementary Questions :: 18.07.2005 23:54 :: crystal :: Replies: 2 :: Views: 611
The main reasons of low impedance bias circuit is to prevent RF to go into DC power supply, and to improve linearity and stability of the amplifier.
Low impedance improve the linearity of the final stage of the bias circuit (reducing the generated distortions), and also low impedance minimize the generated noise by the bias circuit. I don't (...)
Analog Circuit Design :: 12.11.2010 05:32 :: vfone :: Replies: 8 :: Views: 788