Low-loss and highly-selective differential bandpass filter on integrated passive device process

This letter presents a low-loss and highly-selective differential bandpass filter (BPF) with high common-mode rejection ratio (CMRR). The presented integrated passive device process provides high quality lumped elements, and therefore a low insertion loss of the BPF can be obtained. The circuit also uses series-shunt resonators for controlling its differential- and common-mode transmission zeros. Moreover, with a proper choice of circuit component values, a high common-mode rejection can be controlled at a specific frequency without alternating properties of the filter. The chip area of the filter is 3.74 mm(2) including all testing pads. Additionally, the differential BPF achieves a 1.5-dB insertion loss and 11-dB return loss with a 73% 3-dB bandwidth at 2.2 GHz. Finally, the peak CMRR at the frequency of interest is up to 50 dB.