A method for assembling a catheter is disclosed. The method includes printing conductive traces on at least one flexible substrate and encapsulating the at least one flexible substrate to provide for environmental protection. The at least one encapsulated flexible substrate is inserted into a shaft of a catheter. Then, connectors are attached to each end of the at least one encapsulated flexible substrate. One set of the connectors are further attached to sensors located at a distal end of the catheter and another set of the connectors are further attached to electronics in a handle of the catheter.