Series Stubs and Microstrip Technology
You would need 2 pieces of transmission line which have  both lines freely connectable, total 4 wires freely connectable. Unfortunately microstrips have the other wire stucked to the groundplane. You have no way to suddenly rotate the electric field 90 degrees. In MS the E-field is between a wire and the groundplane, in stubs it should be between the wires. In theory this might work if the stubs are verical, perpendicular to the groundplane. But then they aren't microstrip.