A 55 GHz Single-Stage RC Polyphase Filter with LC Matching Network for Low Insertion Loss

This paper presents a 55GHz single-stage RC polyphase filter (PPF) with LC matching network to reduce insertion loss. In the millimeter-wave frequency, PPF has high insertion loss. To reduce the insertion loss, this paper proposes a PPF with LC matching network connected to the input/output ports. The measured result of insertion loss was 17.4 dB for the 4-port average and image rejection ratio (IRR) was 19.2 dB at 55 GHz. The phase error was −4 to 4.4° at 55 GHz and −10.8 to 12.6° in the 50 to 60 GHz range and the amplitude error with respect to the I port was −1.85 to −0.75 dB at 55 GHz and −2.0 to −0.37 dB in the 50 to 60 GHz range. This PPF is fabricated using a 40-nm CMOS process and has an area of 0.45 mm
²
including pads and a core area including the matching network of 0.12 mm
²
.