How to be RF designer??? tips plz help

[ahmed osama]

Dear all

now i have Bsc in Elec. & Comm from 4 years

i have studied basic analog design mainly ( cmos op-amp ,adc , dac...etc) and also digital design and basic VLSI

also i have studied electromagnetic (TL , Rect. WG , Circualer WG, basic antenna)

about tools i worked on MatLab & Simulink . OrCad
have some info. about Ansoft HFSS

BUT ALL THAT from 4 years WITH ZERO Experience !!!

How To start to be RF desinger & wokring from the HOME through internet


thx all

plz help

give ur tips

 

[khouly]

RF experince , need implemetations , and simualtion and read alot of books about MW and analog and RF circuit design

begin with pozar book and ADS or MWO they are great

and if u want anything ahmed , contact me

khouly

 

[mazas3ad]

hi sir
you can start by pozar in the chapter of LNA & OSICLATOR may gonzals help also after reading
give ur self task eg( desgin LNA with at 2ghz NF <2dbm gain >10 db,.....) to do this task
1_choose the active element
2_learn how to use simulation tool like ads
3_design with avalable min dimantion witch in egy ( 300micro_or 150micro)
if u want any help let me know
yours
mohamed assad zaky (bsc E&C CAIRO UV)

 

[raghuram_msc]

Dear Freinds,

RF unlike other domains, requires more 'insights' and knowledge and not mere exposure. One critical problem here is that we cannot moniter circuit parameters like currents, voltages etc directly (b'cos of their wave nature) at every stage of our design, and rather rely upoun more indirect measurement parameters like s-parameters etc. That is why I feel RF is inherently more challenging a domain. This said, becoming a free lance and through RF designer might take anybody quite a long time...!

I personally, to begin with, feel that one should chose basic components like pwr dividers, mixers, fillters, isolators and similar others, and start reading their application notes. As a designer we should try evaluating what are the foremost and basic design parameters needed to design these things. Ofcourse googling would give us tons of basic designs, try implementing/simulating them on RF/MW environment softwares like ADS, MWO (for2D) and HFSS, conserto, CST (for 3D) simulations.
Then one can move on to more complex devices like wave-guides, Amplifiers (LNAs here), RF sources, Transission lines, antennas.....(the list may not end at all..!!). Then finally systems like RF Rx front end etc....

These days even simulation softwares give quite wonderful results...!!!

In the end I would wholeheartedly appreciate Osama's interest in RF/MW domain.

THIS IS THE ONLY DOMAIN OF SCIENCES WHICH IS LAID ON MOST FIRM MATHEMATICAL FOUNDATIONS...!!!

...AND PROBABLY THE ONLY DOMAIN WHERE MATHEMATICAL RIGOUR HAS ENLIGHTENED THE PATH FOR EXPERIMENT..!! (Remember.....Maxwell's Equations precede Hertz's brilliant experiment by 30 years..!!!!)

All the best..!!

Sai

 

[eunderhill]

Reading will help (actually several good tutorials online, will list at end). But you really need to find a way to actually work with rf stuff. I changed from mat'l engineering to rf and there was no easy way to do it from home in front of the computer. A valuable resource is getting involved with the HAM or amateur radio community. They are very creative, very practical, and really love sharing what they know. Conversations with HAM's will also help you understand which parameters that you read about in the books are the most significant in different situations. Good Luck!!

 

[Priyadharshni B]

for everything u need a guide who ll help u ..try doin projects and u ll not only get experience but also a lot of contacts

 

[MI3talk]

I guess the best combination is to read the theory and try out ADS project in design guide to see how different parameters affects the whole circuit.

 

[biff44]

Well, good luck!

Microwave design is counter-intuitive to other electronic design methods. You have to develope some intuition thru design examples.

Some design examples can be done purely on a computer with the right cad program. So you are going to have to get onto a computer program, like Agilent's Genesys, and play around for a few months.

Design amplifiers; lowpass, highpass, bandpass filters; power dividers. In general you need low loss or good gain, good return loss (better than 12 dB), and flat passband ripple (<0.2 dB). You should do designs that are lumped element and transmission line (microstrip).

Once you have accomplished that, you should build some stuff. By some mini circuits amplifier chips, some FR4, and some SMA edge connectors, and build up an amplifier. You need to test it, so you will need at least a signal source and a power meter, although a spectrum analyzer and an oscilloscope will be very helpful too. You can buy cheap stuff on ebay.

Once you have an amplifier that actually amplifies, and does not oscillate, try designing your own amplifier with a FET as the device.

Try making some lowpass and bandpass filters with lumped elements around 400 MHz. If that works, try making some microstrip filters up around 2 GHz.

That is how I would proceed.

Added after 31 minutes:

Here are some examples of stuff you can build at home on FR4:
Amplifier 2 Ghz
Bandpass Filter 780 MHz
Lowpass filter 400 MHz

Notice that they all have a full ground plane on the back. There are lots of drill holes from the top to the back, with a small (very short!) wire soldered onto both sides, to bring ground contact up to the top size.

You can use a sharp hobby knife and score the top of the FR4 board, heat it up with a soldering iron, and strip off the unwanted copper, as in the top side of the bandpass filter.

It helps to have a "designers kit" of inductor and capacitor chips available.

Have at it!

Added after 3 minutes:

 

[rfmw]

Hehe, i see someone is developing RF circuits in the home shack.

Just a little comment:

Amplifier 2 Ghz ... very crappy design
Bandpass Filter 780 MHz ... sloppy, but might even work okay
Lowpass filter 400 MHz ... very crappy design

 

[jonnasi]

Just read as much as you can, books, articles and webpages.
Make yourself a goal. Try to design whole RF part of an transceiver, with PA, LNA, antenna, oscillator and the whole thing.

Simulate your results and try to get wiser.

 

[khouly]

also it need
alot oe practicing on measurment and simulations
it requirs alot of work

khouly

 

[snafflekid]

First get a good book, there is a book by Tom Lee titled "The Design of CMOS Radio-Frequency Integrated Circuits"

Learn and understand the basic impedance matching circuits VERY WELL.

understand the transistor small signal models VERY WELL.

understand two-port networks and how the Z- Y- and S-parameter applies to them

learn how to work with noise sources from resistors and transistors.

Finally design an LNA, it is a useful design experience.

 

[biff44]

Hehe, i see someone is developing RF circuits in the home shack.

Just a little comment:

Amplifier 2 Ghz ... very crappy design
Bandpass Filter 780 MHz ... sloppy, but might even work okay
Lowpass filter 400 MHz ... very crappy design

I gave him stuff that a student could make at home with very little cost. Feel free to contribute something from your own work, if you can.

 

[ahmed osama]

dears if someone succeed to make a master degree in RF could this helps him alot to work in any RF designer company with ZERO experience ??


thanks all

 

[biff44]

You might want to make a complete RF system, without using any system-on-a-chip components.

Maybe make a 915 MHz one way transmit receive system. Buy a VCO, phase lock it to a crystal, FSK modulate it, transmit amplify, lowpass harmonic filter at output, design your own quarter wave antenna.

Then on the receive side, antenna, input bandpass filter, lownoise amplifier, mixer, phase locked local oscillator, IF limiting amplifier, FM discriminator.

Show that you can send data from one loaction to the other. Play with FM deviation and transmit power and test to see the range.

After something like that, you would have a multitude of things to talk about during a job interview: Oscillators, Phase locked loops, antennas, lowpass and bandpass filters, transmit amplifiers, low noise amplifiers, modulation theory, voltage regulation, crystal oscillator stability, etc.

 

[ahmed osama]

Dear all

so what best software tools i can use??

i know very well Orcad tools so can it be used for RF

what aslo about

Advanced Design System 2005A
&
Altium Designer 6


also can i begin without havint adv. hardware tools (osscope / spec. anal..etc)


thanks

all
bye

 

[khouly]

ADS , is great , also MWO office is great

khouly