A 1.3-degree I/Q phase error, 7.1 – 8.7-GHz LO generator with single-stage digital tuning polyphase filter

We have developed an LO generator having 1) a digitally I/Q imbalance tuning polyphase filter and 2) a PLL with a varactor-based VCO and an interleaved charge pump for wide frequency operation. A 90-nm CMOS implementation showed that the equivalent maximum phase error was below 1.3 degrees in 7.1 - 8.7-GHz frequency range.