## Does the length of Transmission line between source and load matter?

With the case of a transmission line between a source and a load there always are the following important points: 1. matching the load to the line, 2. line loss as a function of its length 3. matching the load to the line 4. homogeneity of the line In general, even with a (...)

## Need impedance matching explanation and verification

Hi everyone this is my first post. I am a electronics noob so please be patient with me. I don't understand the concept of impedance matching. Why would you want to increase the impedance in the source, I would think that any increase in the impedance of the source is just wasted power. Maybe my problem is I am thinking (...)

Hi, For unshielded IO cable it is recommended to use low pass filter at the exit of cable. The configuration of the filter depends on the source and loading impedance. Different high and low combination of the impedance requires different filters. But what is the source and (...)

## RF Microwave Tools - part 34 (An impedance matching calculat

An impedance matching calculator. You specify the real and imaginary values for the source and load, specify the frequency of interest, and LCMatch calculates all possible two element matching networks, (LC, CL, CC, LL).

## Looking for a software for PI type matching

Now I am designing a matching circuit for PI type of GSM band, source and load impeadance , operating freq. are available . I need such a software and simulator to design. Thanks. Best regard

## load pull with nonlinear transistor model

M*W*O has a load Pull wizard example located in Examples. Here is the text of this wizard: load Pull Wizard Example This example shows how to use the load Pull Wizard. The example device used is a Curtice FET model. Overview Two different load pull tuners are used, the LTUNER2 and HBTUNER2. (...)

## Audio and Video over Twisted Pair

Thx for the response. Didn't understand the last part fully. The receiver states "Output Level L/R 0,5 Vss on 600 Ohm" So what i need to do is to put the primary of a transformer with 600ohm on the output of the audio signal and then the secondary with 50 ohm (this is the impedance of twisted pair), and then on the receiver

## LNA input and output matching

It is due to the isolation between source and drain, if the isoation is poor the output matching will affect input matching. Also need to make sure the output L network does not change your DC bias of your active device, sometimes people use wrong L network and directly connect the source or (...)

## RFIC and 50 Ohm matching

Impedance matching doesn?t have anything with the distance between stages. Impedance matching is necessarily to get the maximum power transfer between stages, doesn?t matter how far or close they are. Noise Figure matching doesn?t have anything with 50ohms. A Low Noise Amplifier is to design an input matching circuit (...)

## Is matching source and amplifier Zin always necessary?

It depends on amplifier... If the amplifier is a high power amplifier at RF frequencies, "optimum load impedance" should be found and matching is done with this impedance. Or if the amplifier is low power or small signal amlifier, matching should be done with "conjugate matching technique" to obtain (...)

## PA matching questions (conceptual)

load pulling the input and the output in order to generate load circles on the Smith chart is the practical way to do this, either in the simulator or on the bench. Theoretical matching starts to depart from reality with Power amplifiers.

## how to decide the optimum load impedence of power amplifier

The input and output tuning is an iterative process. Get some tuners and try it in the lab on a real part. If your load impedance is varying that much you may want a circulator on the output. The input match that yields maximum power may not have the best return loss. The FET is a voltage controlled current source so you (...)

## Steps for making a LNA with 1420 MHz, noise factor of 0.5 db and gain above 20 db

First : u have to select the transistor , and get the models "S parameter Data" , and nonlinear Model Second : U need to study the matching concepts third : u need to match the amp , for stability and minimum Noise Figure 4th : u need to match the output of the Amp for Max power transfer 5th : u need to (...)

## Power amplifier design for input matching

For power amplifer input matching, does it matter to put the bias network closer to the device or put the matching network closer to the device?. I mean seen from the input the sequency is INPUT+BIAS NETWORK+matching NETWORK+DEVICE or INPUT+matching NETWORK+BIAS NETWORK +DEVICE I find some paper first match (...)

## Matching in power amplifier(PA)

This depends by the matching topology. In the L-networks the Q of the circuit is automatically defined when source and load impedances are set. Pi or T networks allows to select a circuit Q independent of the source and load impedances as long as the Q chosen is larger (...)

## Designing a broadband matching network

Title: Design of a matching Network for Dipole Antennas Abstract: The input impedance of an antenna is highly dependent on the frequency range in which it operates. For an electrically small antenna to operate in a broad frequency range, the antenna must be properly matched. This thesis presents the design of a matching network for a 1-meter mon

## The relation between cable losses and cable length in coaxial cables

thank you for all participations Cable loss is basically independant of impedance matching, a frequency dependant (approximately proportional to squareroot of frequency) and length proportional attenuation. Can you give me any equation about this ?

## regarding the LNA design - matching network Proof

First read about Gain Circles and N Opt Circles Pozar's Microwave Engineering CH 10. So you will understand what Flatulent was explaining. Look at this LNA data sheet (on pg 8). You will see that the input matching circuit is being described by a Noise figure "Circle". Now if you look

## Impedance matching : Interesting Thomas Lee problem

He is very ambiguous in what he is asking about in 2nd ed problem 3.1. Any directions will be appreciated. I have read the chapter very properly and understand the L-match etc but cannot figure out what is he talking about. It seems like some important point the seniors must know. Consider two approaches to matching a purely resistive 7

## does good s11 and s22 affects s21?

Vfone is correct, google Conjugate matching. Also, you will see that a match for optimal Gain will not be the best match for Max Pout in general. Cheers

## conjugate matching , theoretically ,

Read the impedance matching chapter from Bowick book.

## impedace matching differences at low freq & High freq

Hi viper. You can match impedances at one frequency, or at another. Not at both. The flaw is in the person(s) who write an article or make a comment about an impedance value, in general the practice has been overseen so badly that nobody sees as wrong. Anyone who talks about the impedance of a device, MUST express "at such frequency". It d

## Narrowband Matching Network to Broadband Network

An exact matching using only L and C components is most likely not possible. I guess, the best way is to accept a certain mismatch and roughly compensate the capacitive source impedance for the center frequency with an inductor. Using transformers and transmission line segments can offer additional options (...)

When you drive pure capacitive load (typical example is piezo-actuator) will required medium impedance at several k-Ohm. For many op-amp, you got to choose if you are driving data or video signal. For video, op-amp for this purpose will have Rout at 75-Ohm by default. For data, op-amp for this purpose will have Rout at 50-Ohm by default. The

## Matching Network using ADS smith chart utility:

hi, i want to match Z-source and Z-load impedance at 2GHz which are present in the attached file, using ADS Smith chart utility. I am confused about the behavior of this utility. At 2 GHZ Z_load is 19.4+j*39.9 ohm. It is provided in the source and load termination (...)

## How to get the desired Noise Figure Circle and Gain circle for Low Noise Amplifier.

etmabreu sir, As you told sir, I added DC bias at the both gate, drain with 2 volts and quarter wavelength. I am sorry , couldn't get the desired result, but somewhat better ,better result than the earlier. Here with I am attaching the MWO file btv_murthy, if you look at the transistor's da

## Matching input signal with dominated capacitive part

I have input signal where capacitive part is dominated. Do you mean a mostly capacitive source impedance? I have input signal where capacitive part is dominated. What demands compensation? Are you required to achieve impedance matching? However I am getting too narrow characteristic. As result it very se

## RF Microwave Tools - part 5 ( Phase-locked loop designer)

Robin Hood Post sorted: Diode Model Parameter Extraction from Manufacturers' Data Sheets PIN Diode Model Parameter Extraction from Manufacturers' Data Sheets Displays RF power and voltage relations

## RF Microwave Tools part 1 - part 64

9705-1.pdf Diode Model Parameter Extraction from Manufacturers' Data Sheets 9708-1.pdf PIN Diode Model Parameter Extraction from Manufacturers' Data Sheets dbm.zip Displays RF power and voltage realtions network.zip Either an AC network analysis or RF design tool pll.zip Phase-locked loop designer

## Filter Design - no response on the GPB

Hi, I know the problem with my filter is high impedance. I had asked the Maxim tech help on how about lowering the impedance requirements. (Actually the output impedance of the mixer is around 100-400 ohms but an impedance of 4K is recomended.) I got the following answer. "As the filter impedance is lowered, the mixer ou

## How to model a SAW Filter

normally SAW provider supply the s-parameter of SAW filter with matching ckt (LC) parameter... for balance scheme they measure the s-parameter with 3-port or 4 -port VNA and match the filter with LC. However, If you request the test sample.... they send test sample soldered on PCB with 1:1 or 4:1 balun and balun loss data sheet... (...)

## can we stabilize this transistor?

thanks for the work you did. It is a school project. I will talk to the professor about this issue. The best matching network I used gave me instability between 100MHZ and 400 MHZ, and other regions were stable. The problem I have to make sure it is stable in the entire frequency band (100 Mhz to 6 Ghz). I have used (...)

## questions about microwave amplifier measurements

Hello ayhz2002 ! What amplifier design do You need: narrowband or broadband ? If You need the narrowband design - You must make the good in/out matching only on 5.5 Ghz, but in narrowband the 'good' matching usually is S11,S22<-30 dB. In this case You must aim at minimum gain on out the (...)

## Why we need to add input buffer for RF amplifier?

I once designed a three stage power amplifier. I suppose that in this case your buffer is an impedance matching state with low noise (LNA) and also amplififyes the input power to the desired level for the next stage. I hope this helps, Best regards, mimoto

## How to change entry or exit port impedances?

The port impedance is set by maximum power transfer (conjugate matching). Typically 50 Ohms. However, impedance transformers are usually adopted to match and alter the port impedance. Common-source amplifiers with degenration are a prime example where impedance transformation is adopted to suppress noise figure. Colombo2

## RF output power vs Frequency

Power amplifiers are very interesting circuits. There is always constraint points that limits the circuits. It's called as "Fano Limits" and depend on many parasitic and behavioural and physical devices in the semiconductors. Most probably the model which has been used to simulate the transistor is no longer valid at 2GHz. (...)

## Help me design a Power Amplifier Class C at 60MHz

hi I'm using MRF171A, problem appear in matching circuit...when I get tuned operation around the operating frequency gain increase significant and I have stability problem. in Cripps book, he say that adding small Resistance will give unconditional stable operation :roll: ...Ok, after add this part I have the surprise, gain fall a

## Questions about s-parameter simulation of LNA.

As you said, sometimes it is intentional to merge bias/match network and this is obvious. The bias network, if not well designd can impact on signal, so on s parameter of the LNA. Also the layout is fundamental, of course. But I do not really understand your problem: could you be more detailed? Furthermore, do not expect perfect matching (...)

## Maximum Power Transfer??

I have a very basic question. Why are we concerned with Maximum Power transfer ? If we do maximum Voltage Transfer, like having infinite input impedance to a amplifier for voltage amplification, how would this system be inferior to a system having a matched input impedance to the source??? I hope I will get many responses to this

## Want to understand matching

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 desired results. The networ

## Frequency Multipliers and Dividers

Hi Faisal, 1- frequency multipliers are used as signal generation technique, permeting one to abtain and utilize the harmonics of a fundamental frequency technique, meaning if your input frquency is "f" you can get 2xf or 3xf ... 2- one of the approches that is been used for analog divider and multiplier is gilbert cell multiplier, there is a

## Impedence Matching...

impedance matching commonly use in the high frequency aplifiere design. you can use the matching for this reson 1-obtain the max of gain 2-minimum the noise 3-transfer the max power to load 4-reflection of eergy is low and so on. you can use the RF circuit design by Ludwig in the EDA book download for (...)

## 50 Ohm matching with pads

For high speed analog design, I assume you need 50 Ohm matching at the input so as to ensure maximum signal power transfer. How do you achieve this without using LC matching? Do you just use a resistor or do you play with the ESD or what? Any advice would be greatly appreciated...

Seems that the ground of emitter is connected to the bottom ground layer only, through vias. Even if you will lose inductance try to connect to the top ground also. Between LNA output and PIN attenuator try to use a low-pass topology matching circuit and tune this one for a compromise of all impedances of the attenuator (from low to high (...)

## What is buffer and its use, when doing circuitry design?

a buffer is a unity gain amplifier. it may be used for impedance matching problems. for the example u have given buffer is not needed as per my knowledge. but if u see the signal going down after connecting the output to the next stage then u might need a buffer.

## L matching network Q????

Hi Willem, I just want to know the Q you mentioned is for which network. As we know for L network, the Q is fixed by the input resistance and output resistance. Since you want to match 2.3 ohm to 3.3 -j 3.94, you should include the -j3.94 to your network first, so the matching is from 2.3 to 3.3, the Q is fixed if you still want to (...)

## Analog Layout and Digital ?

When you do some signal analog layout, the matching and shielding should be considered, and when you do some power analog layout, the safe of the device should be considered. By the way many tools can help you do some digital layout but analog layout design is a art which more depend on the designer's experience.

## 1500W Inverter Full Schematics And Pcb

I propose the new type transformer less inverter whose basic topology should be buck boost converter. The greatest characteristic of this inverter would be that it will has only one stage to generate AC power. It means that s

## How to measure the output impedance of an active device?

Hi, For a passive device you can calculate your input and output impedance using the measured S parameters (from your network analyzer). To calculate the input impedance you will need your input and output reflection coefficients. For a properly matched output your input reflected coefficient will be S11, and Zin will be: Gammain=S11 (...)

## Oscilloscope 1MOhm VS. 50Ohm input resistance

bittware, In RF work, many circuits are designed to operate with transmission lines with a 50 Ohm characteristic impedence. Idealy this impedence is purely resistive. Providing a 50 Ohm input impedance at a 'scope input allows measurements without disturbing the impedance matching of the circuit under test. For example, passive filters that ar