Crosstalk Analysis Between Non-Parallel Coupled Lines Connected With Vias in a 4-layer PCB

Multi-layer PCBs are often used in compact microwave circuit design as density of PCB layout is increased. In this paper, the crosstalk between non-parallel coupled lines connected with vias in a 4-layer PCB is investigated theoretically based on the circuit-concept approach. Non-parallel coupled lines connected with vias in a 4-layer PCB are divided into three sections, which are coupled microstrip lines and upper via section, center via section, and lower via and coupled microstrip lines section, respectively. Each section is represented by ABCD matrix. By cascading these three ABCD matrices crosstalk between non-parallel coupled lines connected with vias in a 4-layer PCB is approximately calculated. The validity of this theoretical approach is verified by comparing the calculated results with the simulated ones using HFSS