# Is the TAOGLAS PCB Antenna Too Long on Purpose?

I have been using a TAOGLAS 915MHz PCB antenna for my remote control. I'm about to redesign the PCB and wanted to try including my own PCB antenna on the board. For the 915MHz band, a quarter wavelength is ~80mm, however I measured the trace on the TAOGLAS board using a ruler, and got something closer to ~117mm. The difference between these is too big to be attributed to inaccuracies due to the use of a ruler, so I was wondering why the trace length they use is different than the theoretical optimal value.

Additionally, I was thinking of making my trace ~80mm, and then putting a solder bridge connecting it to another trace for a total of 117mm. I know this wouldn't be as great as a single trace of length 117mm, but is there a reason this wouldn't work for testing purposes.

I've found online that the optimal length for an antenna is 1/4 of the wavelength (although now typing this I realize this probably does not apply to PCB antennas, as that research was done for a monopole wire antenna). I have tried looking for resources on how to design a PCB antenna, but could only find equations for a patch antenna. I used an online calculator, and used the bounds of 3.8-4.8(through quick google search) for the dielectric constant of FR-4 just to get an idea of what it would look like, but it is wayyyy too big ($$>7,000 {mm}^2$$). If anyone has any resources describing how to design a monopole antenna PCB send them my way.