Does anybody can give some RF PCB material selection guide?
Or maybe give us the tips about how to choose the PCB material while we design RF board?
Does anybody can give some RF PCB material selection guide?
Or maybe give us the tips about how to choose the PCB material while we design RF board?
I have got a PCB sample from Rogers corporation in order to make my VSWR-meter. Nonetheless I have got some trouble to "translate" figures from maths to real lines on the PCB.....
I worked with this calculator:
http://www1.sphere.ne.jp/i-lab/ilab/tool/ms_line_e.htm
As an example I have got these figures for a RF4 PCB :
Operating frequency : 2450.000 MHz
Dielectric constant :5.4
Substrate thickness : 1.600 mm
Microstripline impedance : 50 ohms
Microstripline physical width : 2.53 mm
One wavelength (360°) : 61.6 mm
Quarter wavelength (90°) : 15.4 mm
Hence my questions below ==>
It leads to a lambda= 15.4 x 4= 61.6 mm inthe PCB instead of 300/24.5 (122.4 mm) in the air, right ?
Does it means that the velocity factor is 61.6/122.4 = 0.503 ?
Is the length of the 50 Ohm line on the PCB a mandatory request or its length is pointless ?
In other words may the line be of any length ?
About the forward and the backward lines:
Do they have a 5O Ohm impedance as well or they could be of any width ?
Do they have any length or they must be as long as the main line ?
What is the depth of the gap between the main line and the backward and forward ones ?
Could anyone tell me where I could find some theorical work about this concern ?
I would like to make my own VSWR-meter to "refresh" a bit my knowledge in the field of RF since I didn't make anything for a lot of years in this field. I feel like an idiot.....
Thanks a lot to you all and, above all,
HAPPY NEW YEAR
Richard
I have got a PCB sample from Rogers corporation in order to make my VSWR-meter. Nonetheless I have got some trouble to "translate" figures from maths to real lines on the PCB.....
I worked with this calculator:
http://www1.sphere.ne.jp/i-lab/ilab/tool/ms_line_e.htm
As an example I have got these figures for a RF4 PCB :
Operating frequency : 2450.000 MHz
Dielectric constant :5.4
Substrate thickness : 1.600 mm
Microstripline impedance : 50 ohms
Microstripline physical width : 2.53 mm
One wavelength (360°) : 61.6 mm
Quarter wavelength (90°) : 15.4 mm
Hence my questions below ==>
It leads to a lambda= 15.4 x 4= 61.6 mm inthe PCB instead of 300/24.5 (122.4 mm) in the air, right ?
Does it means that the velocity factor is 61.6/122.4 = 0.503 ?
Is the length of the 50 Ohm line on the PCB a mandatory request or its length is pointless ?
In other words may the line be of any length ?
About the forward and the backward lines:
Do they have a 5O Ohm impedance as well or they could be of any width ?
Do they have any length or they must be as long as the main line ?
What is the depth of the gap between the main line and the backward and forward ones ?
Could anyone tell me where I could find some theorical work about this concern ?
I would like to make my own VSWR-meter to "refresh" a bit my knowledge in the field of RF since I didn't make anything for a lot of years in this field. I feel like an idiot.....
Thanks a lot to you all and, above all,
HAPPY NEW YEAR
Richard
Hello Richard,
Based on the questions you have put forth, It looks like you might be missing a little bit on your understanding of RF theory. Radio propagation is a little different then low frequency theory. Velocity should not be something you need to consider. However the length of the trace might be an issue depending on a variety of factors.
It might not be a good idea to build this board without some help. The devil is in the details. If you like I am available for the next month or so until I start my next project in March. I can give you a hand reviewing your design and helping you get on the right track.
Give me a call or drop me an email if you are interested. www.pinterec.ca
Contact: Chris Pinter http://www.pinterec.ca/contact-us/
Richard - Take a look at the book:
By: TC Edwards
On Amazon you can search the table of contents and it has a nummber of chapters and presents Coupler Design Equations.
HTH - Steve H.