Synthesized Design of Millimeter-Wave Low-Loss Wideband Bandpass Filter and Filtering Impedance Transformer in 90-nm (Bi)-CMOS Technology

This paper introduces a rapid filter synthesis method that utilizes the improved Chebyshev function to design versatile broadband on-chip filters with multiple (N) independently controlled transmission zeros (TZs). It eliminates the constraints of narrow bandwidth associated with traditional filter synthesis method. A set of three universal lumped LC circuit topologies are proposed to achieve arbitrary bandwidth, arbitrary order, and different distributions of N TZs. Additionally, we introduce an innovative approach to simultaneously extract components from both sides of the circuit during lumped LC circuit synthesis, which reduces accumulated numerical errors and improves the design speed. Several filters with the same 50–70 GHz passband but different TZs distributions, and an ultra-wideband filter from 30–90 GHz are successfully synthesized using the proposed circuit topologies and extraction method. Our proposed method can also be extended to design filtering impedance transformers for on-chip systems that surpasses the traditional RF design flow using 50 Ω interface and offers the combined benefits of component reduction and minimized system loss. Using the proposed design methodology, we fabricated a 90-nm SiGe BiCMOS on-chip filter which exhibits a low insertion loss of 1.5 dB at 59.16 GHz and a fractional bandwidth of 34%, achieving one of the best reported loss performances among silicon integrated filters to date. This research contributes to low-loss on-chip filter design methodology for universal design specifications and offers a design tool that can achieve high design speed and desired performance, enabling the promise of on-chip filter synthesis for emerging wireless technologies.