Hi .I am making a pcb with a gsm module sim800c . datasheet,hardware design guide .now i have to design tracks for the antenna . so i have come up with 4 designs, please critique my designs. this is not my final design .
the top plane is VCC . and the bottom plane is GND .
there are no high frequency tracks nearby .
antenna is operating at 833 MHz.
the track width is 0.5 mm
if you need anything else please ask for it.
design 1 . in this design there is no isolation . no sheilding vias just the track.
q1 if my design has a lot of isolation . then what is the use of sheilding vias. as they are not connected to anything.what will they do ?
q2. what is the difference between design 2 and design 4 ? what are the advantages and disadvantages of adding sheilding vias.
any other help is also appreciated.
MarkT:
Not enough information. The dielectric constant is required to calculate the track width. Ceramic could mean anything from BeO to BaTiO4 to diamond!until the microstrip is correctly proportioned for 50 ohms, no point doing anything else.
i also dont know tahat. lets say that we are using the standard pcb or most widely and commonly used pcb that any fab house offers . then what ? then what will i have to calculate ?
how much difference does the type of material makes ? does it akes a very big difference ? or a very small difference ?
can it bbe compentated in any othher ways ? like using cap and res of different values to match the impedance ?
let us also assume that everything is calculated an i am ready to make the design (not a rf antenna ) [only a trace between connector ] the can someoone please answer q2 ?
You really have to know what you are doing to design useable RF PCBs, and those who do know what they are doing, throw away the first few designs, after testing them using very expensive equipment.
Plenty of design info on the web. You will save yourself a lot of time and learn a great deal more by studying such material, rather than posting on random forums.
manveen_singh:
i also dont know tahat. lets say that we are using the standard pcb or most widely and commonly used pcb that any fab house offers . then what ? then what will i have to calculate ?
You need the fab house to tell you the technical details of their particular ceramic board material, it ought to be very accessible information. Otherwise you'll have to measure it yourself (at 800MHz).
thanks for your help . but this is not what i am looking for. this is just antenna designing . as i have stated earlier. i am not designing an antenna . i just have to make the connector.