Any drawbacks of using very thin lambda/4 open microstrip line in harmonic filter?

[Terminator3]

Simulation shows that the thinner line is, the wider band would be filtered around lambda/4 center frequency. Is anything wrong with this approach? I mean make this line really thin, almost like for DC signals. I want to filter out fundamental using this approach, without using microstrip/hairpin filter.

 

[vfone]

A microstrip notch made by a thin L/4 line is not very consistent in production when try to reject a carrier, because small variations in the PCB process will change the notch frequency.
Meantime, a thin microstrip line is actually an inductor (see online for equations) and this can be helpful in microwave frequencies making a low pass filter just adding capacitors at each end.
For example in a 50 ohm environment, a 5nH line with 1.2pF at each end became a LPF with 3dB cut-off at 3GHz.
Sometimes you get lower insertion loss through a thin microstrip line "matched" with capacitors than without capacitors.
The inductance of the microstrip line is mainly given by its length, thickness, and distance from the ground.
Ideally is better to do not use ground in this situation, because you get greater inductance for a shorter line.