A stripline is constructed with a flat conductor suspended between two ground planes. The conductor and ground planes are separated by a dielectric. One advantage of the stripline is that there is an improve isolation between adjacent traces when compared with the microstrip.

Stripline Transmission Line Models

As for a microstrip transmission line, the impedance Z0 of a stripline depends on the ratio of the conductor width and the separation between signal and ground planes. In case of a symmetric stripline, Z0,SS can be computed according to the formulas contained in the document IPC-2141A [1], in particular paragraph 4.2.4.

The characteristic impedance computation can be broken down into two cases, one for a narrow signal conductor and one for a wide signal conductor.

For the narrow signal conductor, that is for w/b < 0.35, the appropriate formula for the characteristic impedance, Z _0,SS, is:

Eq. 1

where: b = 2h + t

and:

Eq. 2

For the wide signal conductor, that is for w/b ≥0.35, the appropriate formula for the characteristic impedance, Z_0,SS, is:

Eq. 3

where:

Eq. 4