Miniaturized full differential bandpass filter design embedded in organic substrate

A miniaturized full differential bandpass filter with significant area reduction is presented. To achieve miniaturized circuit area and effectively reduce cost, the transformer based structure and organic substrate (FR-4) were adopted to realize the bandpass filter design. The coupled resonator synthesis method was used, and properly shifted tapped feed-line to obtain better impedance match at ports. The circuit area (6.6 mm × 8.3 mm) is effectively reduced and achieves 97.72% area reduction. In the differential mode operation, the bandpass filter for wireless local area network (WLAN) IEEE 802.11a (5 GHz) applications was derived good insertion loss (3dB) and CMRR (>;20 dB). The embedded passive component technology was really verified the feasibility and provided system design flexibility for System in package (SiP) application.