Dielectric loss for coplanar line or microstrip line

For two layers PCB of FR4 with thickness of dielectric 0.2mm,
Which is lesser regarding dielectric loss, coplanar line or microstrip line ?
Operation frequency is 1GHz

Line width of 50ohm is about 0.3mm for both coplanar line and microstrip line.

CPW have the fields more concentrated in the dielectric, when narrow microstrip lines have more energy field in the air (wide microstrip lines are different, they have more energy in the substrate than in the air).
The dielectric loss would affect more the CPW than affect the narrow microstrip lines, but narrow microstrip lines are more affected by the radiation losses so their insertion loss is higher.

Attached figures are results of LineCalc on Keysight ADS.

Loss_dB/cm are almost same when considering dielectric loss and copper loss.

According to the study below, microstrip lines look less lossy comparing to coplanar lines.

http://mpd.southwestmicrowave.com/sh...h%20Connectors

See page 27.

The measurements are taken at 5 GHz and above, microstrip's loss/inch values are always lesser. There is no measurement around 1 GHz, most probably it goes like that down to 1 GHz.

This includes radiation loss.

Regarding only dielectric loss and copper loss, loss of CPW without GND plane could be lesser than MLIN especially for case of very short line on very thin dielectric.
It is almost capacitor than transmission line.

Radiation loss for very short line at 1GHz could be negligible compared to dielectric loss and copper loss.