short transmission line as inductor

Hello, I want to realize a 3-order lowpass filter on chip. F cut @ 20GHz
A series inductor should be used.
I'm not sure that spiral inductor will have a good performance near that freq. And series transmission line is difficult to realize.
Can I make the trans line as

I__________
__________|
I

or use CPW?

Which structure( spiral, u-shape line, cpw) may have best perf?
i mean para effect is lowest

thanks for advice.

take care about the power that u r working with.
and c if u can made the size of the line !

I think that at 20 GHz the spiral inductor will have about 1/4 turn with a internal diameter of 1 mm ( say not possible to realize ).
For this reason the only solution is the sripline or microstrip.

Mandi