Miniaturised 60 GHz rectangular ring bandpass filter in 90 nm CMOS technology

A dual-mode rectangular ring bandpass filter at 60 GHz using 90 nm CMOS process is presented. Transmission lines in the ring are converted into meander lines to reduce the size of the ring. Capacitors are also added at four corners of the rectangle ring to miniaturise further the core size of the filter to 355 × 335 μm. The measured insertion loss is 4.2 dB at the centre frequency 59 GHz with 14.5 GHz of 3 dB bandwidth. Return loss is better than 12 dB at the passband. Measurement results agreed well with EM simulation.