transmission line length question

Hi Guys
I had a simple question need to confirm. I want to make a half wavelength transmission for example at 2 GHz at PCB board. Suppose the PCB have a dielectrical constant of 4. What will be length of the half wavelength transmission line?
15/2=7.5 cm
or I need to consider the dieelectrica constant of the PCB (FH4).
Can anyone help on this?
Thanks a lot

or I need to consider the dieelectrica constant of the PCB (FH4).

Click to expand...

Yes. If the electrical field would be completely in the dielectric, the wave length is shortened by a factor of sqrt(Er). For microstrip line with part of the field in air, the reduction factor will be around 1.6..1.8. A PCB transmission line calculation program can give accurate estimations for ZL and propagation constant. If you know the characteristic C and L per length unit, you can calculate it yourself from elementary transmission line equations.

where can find the PCB transmission line calculation program? ADS??
I do not know the characteristic C and L per length unit

FvM said:

Yes. If the electrical field would be completely in the dielectric, the wave length is shortened by a factor of sqrt(Er). For microstrip line with part of the field in air, the reduction factor will be around 1.6..1.8. A PCB transmission line calculation program can give accurate estimations for ZL and propagation constant. If you know the characteristic C and L per length unit, you can calculate it yourself from elementary transmission line equations.

Click to expand...

---------- Post added at 21:31 ---------- Previous post was at 21:12 ----------

how about a microstrip line?
Is it straight forward?
thanks

liletian said:

where can find the PCB transmission line calculation program? ADS??
I do not know the characteristic C and L per length unit

Click to expand...

There are many calculation tools, e.g. this free tool from AWR

Hi FVM
Thank you very much.

liletian said:

where can find the PCB transmission line calculation program? ADS??
I do not know the characteristic C and L per length unit

Click to expand...

ADS has a built-in tool called LineCalc that will do this for you. You need to be in a schematic design, then go to Tools, LineCalc, Start LineCalc. The drop-down at the top-left lets you access a variety of stripline/microstrip structures. The PCB and metal material parameters are entered at the left (height, metal thickness, resistivity, dielectric constant, prop constant, etc). Plug in your design/center freq at the bottom left, and characteristics on the right. Once that's all in, use the two buttons in the middle to Synthesize or Analyze the structure.

descent amount of explanation is given on half wave and quarter wave transmission lines with single example, See if the link is useful
**broken link removed**