A 0.01–26 GHz single-chip SiGe reflectometer for two-port vector network analyzers

This paper presents a single-chip 0.01–26 GHz reflectometer for two-port vector network analyzers (VNA). The reflectometer consists of a bridge coupler integrated together with two wideband heterodyne receivers. For wideband operation, a resistive bridge coupler is used with a directivity of 33 dB up to 26 GHz. Also, a high-linearity receiver channel is designed so as to accommodate 10 dBm of RF input power to the reflectometer. The SiGe chip is 1.8 mm2 and consumes 640 mW from a 3.3 V supply. The dynamic range of the reflectometer chip is 127±2 dB at 0.01–26 GHz with an IF resolution bandwidth (RBW) of 10 Hz. The chip is placed on a printed circuit board (PCB), and RF, LO and DC bias are connecterized. Measurements of several device-under-test units (DUTs) with a two-port 0.01–26 GHz VNA composed of two reflectometer chips shows excellent agreement with a commercial VNA, with a magnitude and phase difference of < 0.2 dB and < 2° respectively for Su. Two-port measurements also show an 821 dynamic range of 80 dB, limited by the measurement setup and not by the chip. To our best knowledge, this is the first demonstration of a VNA operating from 10 MHz to mm-wave frequencies with the capability of measuring −80 dB of S21 as well as minimal magnitude and phase difference compared to state-of-the-art VNA measurements.