LTCC-MLC balun for WLAN/Bluetooth

A low temperature co-fired ceramic (LTCC) multi-layer ceramic balun is presented in this paper. This balun is designed in the ISM band for WLAN or Bluetooth use. It uses multi-layer structure, meander lines, and multi-section coupled-lines with various coupling coefficients. The characteristics of phase balance and amplitude balance are extremely excellent because of its symmetric structure and a transmission line trimming section. Measured results of the LTCC-MLC balun match well with the computer simulation.