A study on the open end effect of coupled transmission lines

This paper studies the open end effect in parallel coupled transmission lines. The parallel coupled transmission line that has an open ended through port and an isolation port connected with 50 ohm transmission line is simulated using an electromagnetic simulation tool. The equivalent circuit having a negative phase is extracted using the Designer V4(Ansoft co.) de-embedding technique. The open end effect is verified by de-embedding on both sides of the open ended line. The equivalent circuit's capacitance and inductance are also shown.