On-chip tunable low pass filter with improved stopband using new cross coupled topology

• Main Authors: Ma, Kaixue, Mou, Shouxian, Yeo, Kiat Seng, Lim, Wei Meng
• Other Authors: School of Electrical and Electronic Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/101903; http://hdl.handle.net/10220/16360
• Institution: Nanyang Technological University

A new type of low pass filter with ultra-wide rejection band and compact size by using a cross coupled topology (CCT) is proposed. The topology and circuit model are adopted to design the on-chip low pass filters through parameter extracting and electromagnetic optimization. One of the designed CCT low pass filters with 1-dB cutoff frequency fc of 2.2 GHz demonstrates the stopband rejection of 30dB up to 20 fc i.e. 45 GHz and rejection of 20dB up to 52 fc i.e. 110GHz. The measured passband insertion loss is less than 2.2 dB. The size of the low pass filter is only 350 μm by 280 μm or 0.0089 λg × 0.0071λg (λg is the guide wavelength on silicon at cutoff frequency). With the size chip area, a tunable CCT LPF is introduced to further improve the stopband rejection and rolloff.