Compact balanced band pass filter for 3.3GHz – 3.9GHz WiMAX applications

A small form-factor balanced filter for WiMAX applications is developed using silicon-based IPD technology. The balanced filter (1.2 mm times 2.0 mm times 0.4 mm for flip-chip version, and 1.2 mm times 1.6 mm times 0.25 mm for wire-bonding version) is the smallest device achieving similar electrical response, to the best of our knowledge. The insertion loss at the pass-band is 2.0 dB. The attenuations at 800 MHz, 1900 MHz, and 2400 MHz (cellular and WiFi bands), are 40.0 dB, 30.0 dB, and 25.0 dB, respectively. The common-mode rejection is better than 20.0 dB, with amplitude imbalance of 0.4 dB and phase imbalance of 10.0 degree. The small footprint and the low profile of the device make it a very good candidate for WiMAX modules or SiP. An advanced design methodology has been adopted based on EM simulation for fast design cycle time. Good correlation is seen between simulation and test.