A 140-GHz Direct Raised-Cosine Envelope-Shaping Transmitter with Integrated ILO Phase Shifter
Information Theory
Summary
The authors developed a 140-GHz transmitter that directly shapes the signal's amplitude in a way similar to a smooth raised-cosine curve, avoiding complicated baseband processing. Their design uses multiple discrete radio-frequency envelope levels to achieve this shape, allowing data rates up to 8 gigabits per second with good signal clarity. They also included a phase-tuning feature that can finely adjust the signal's phase digitally and continuously, which is useful for antenna arrays. Overall, their transmitter combines power output and fine control for fast wireless communication at very high frequencies.
Authors
Haoling Li, Najme Ebrahimi
Abstract
A 140-GHz transmitter with direct raised-cosine-like envelope shaping and wide-range phase tuning is presented in 90-nm SiGe BiCMOS. The proposed architecture relaxes conventional baseband pulse shaping and high-speed digital-to-analog converters by directly synthesizing 3-level and 5-level RF envelope states that approximate a raised-cosine waveform, enabled by a 23-dB modulation dynamic range. Measured results demonstrate data rate up to 8 Gbpers with 34-dB sidelobe suppression. To support scalable phased-array applications, an injection-locked-oscillator phase-tuning path is also integrated, providing 22.5deg digital phase resolution together with continuous analog tuning over more than 360 deg. The transmitter achieves up to 2 dBm output power and combines direct RF envelope shaping with wide-range fine phase control for sub-THz wireless links