35-60GHz Switchless IF Bi-Directional Amplifier Using 65nm CMOS for 300GHz-Band Transceivers

The escalating demand for enhanced wireless communication performance has spurred significant interest in sub-THz frequency bands, notably the J-band (220-325GHz). This band stands out due to an established IEEE standard (802.15.3d), which supports channel widths of up to 69GHz. However, designing amplifiers for such high frequencies requires innovative approaches, such as adopting mixer-last or mixer-first topologies, where the IF amplifiers provide the necessary amplification. Additionally, achieving satisfactory power levels involves the integration of phased-array structures, underscoring the importance of area minimization [1], [2]. This paper delves into the methodologies associated with device de-embedding and modeling. It further details the design of a bi-directional IF amplifier, realized in a 65nm CMOS process with a core area of 1.45x0.3mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The amplifier’s measured performance achieves a 14dB gain across a 25GHz bandwidth (35-60GHz) in both transmission directions, an 8.4dB noise figure (NF) for the LNA, and a 7dBm OIP3 for the PA. It also supports 125Gb/s communication employing 32QAM modulation, which significantly advances sub-THz wireless communication.