A 6-Bit Ku Band Digital Step Attenuator with Low Phase Variation in 0.13-μm SiGe BiCMOS

Abstract

A 6-bit Ku band digital step attenuator with low phase variation is presented in this paper. The attenuator is designed with 0.13-μm SiGe BiCMOS process technology using triple well isolation N-Metal-Oxide-Semiconductor (TWNMOS) and through-silicon-via (TSV). TWNMOS is mainly used to improve the performance of switches and reduce the insertion loss (IL). TSV is utilized to provide approximately ideal global current ground plane with low impedance for the attenuator. In addition, substrate floating technique and new capacitance compensation technique are adopted in the attenuator to improve the linearity and decrease the phase variation. The measured results show that the attenuator IL is 6.99–9.33 dB; the maximum relative attenuation is 31.87–30.31 dB with 0.5-dB step (64 states), the root mean square (RMS) for the amplitude error is 0.58–0.36 dB and the phase error RMS is 2.06–3.46° in the 12–17 GHz frequency range. The total chip area is 1 × 0.9 mm2.

A Ku-Band GaAs Multifunction Transmitter and Receiver Chipset

“…Finally, 4.0-dB and 8.0-dB attenuator cells are designed with the structure shown in Figure 2c, where a capacitor, CP2, is connected in parallel with RP2. This not only reduces the phase imbalance but also prevents the bandwidth reduction occurring in high attenuation cells [16][17][18]. Figure 3 shows a full schematic and micrograph of the 5-bit digital attenuator.…”

“…Figure18. Measurement results of the multifunction transmitter in the reference state: (a) gain and matching performance, (b) output power and power gain versus input power at 15 GHz.…”