A W-Band +7dBm Output Power Direct Digital RF Transmitter Using Manchester-Encoded 1-Bit BPDSM and Frequency Tripler

This paper presents the first demonstration of a W-band high-output-power direct digital RF transmitter using a Manchester (MAN)-encoded 1-bit band-pass delta-sigma modulator (BPDSM) and a frequency tripler. Unlike conventional architectures, this direct digital RF transmitter eliminates the need for analog up-converters (i.e., a local oscillator (LO) and a mixer), and is composed solely of commercial-off-the-shelf (COTS) components. The 5th and 6th image signals (30 GHz and 33 GHz) of a 21 Gbps MAN-encoded 1-bit BPDSM signal (fundamental frequency of 1.5 GHz) are applied to an active tripler. The 17th image component (93 GHz) is then extracted from the tripler’s output as the transmission signal. The measured results show the successful generation of a 93 GHz signal from a 21 Gbps digital signal using the direct digital RF transmitter without up-converters. The measured 5 Msps-QPSK signal at 93 GHz achieves the output power of +7.0 dBm, ACLR of -25.2 dBc, and EVM of 6.4%. Furthermore, the measured 5 Msps-16QAM signal achieves the output power of +3.1 dBm, ACLR of -23.5 dBc, and EVM of 7.3%.