A High-Efficiency 142-182-GHz SiGe BiCMOS Power Amplifier With Broadband Slotline-Based Power Combining Technique

• Published in: IEEE journal of solid-state circuits Vol. 57; no. 2; pp. 371 - 384
• Main Authors: Li, Xingcun, Chen, Wenhua, Li, Shuyang, Wang, Yunfan, Huang, Fei, Yi, Xiang, Han, Ruonan, Feng, Zhenghe
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-02-2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bandwidths; Broadband; Broadband power combiner; Circuit faults; Coplanar waveguides; Efficiency; grounded coplanar waveguide (GCPW); high-efficiency; hybrid power combining; Impedance; Impedance matching; Insertion loss; Microstrip; Millimeter waves; mm-Wave power amplifier (PA); Power amplifiers; Power combiners; Power gain; Power generation; SiGe; Silicon germanides; Slot lines; slotline; Topology; transformer
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2021.3107428

In this article, a high-efficiency broadband millimeter-wave (mm-Wave) integrated power amplifier (PA) with a low-loss slotline-based power combing technique is proposed. The proposed slotline-based power combiner consists of grounded coplanar waveguide (GCPW)-to-slotline transitions and folded slots to simultaneously achieve power combining and impedance matching. This technique provides a broadband parallel-series combining method to enhance the output power of PAs at mm-Wave frequencies while maintaining the compact area and high efficiency. As a proof of concept, a compact four-to-one hybrid power combiner is implemented in a 130-nm SiGe BiCMOS back-end-of-line (BEOL) process, which leads to a small die area of 126 <inline-formula> <tex-math notation="LaTeX">\mu \text{m}\,\,\times </tex-math></inline-formula> 240 <inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> and a low measured insertion loss of 0.5 dB. The 3-dB bandwidth is over 80 GHz covering the whole G-band (140-220 GHz). Based on this structure, a high-efficiency mm-Wave PA has been fabricated in the 130-nm SiGe BiCMOS technology. The three-stage PA achieves a peak power gain of 30.7 dB, 3-dB small-signal gain bandwidth of 40 GHz from 142 to 182 GHz, a measured maximum saturated output power of 18.1 dBm, and a peak power-added efficiency (PAE) of 12.4% at 161 GHz. The extremely compact power combining methodology leads to a small core area of 488 <inline-formula> <tex-math notation="LaTeX">\mu \text{m}\,\,\times </tex-math></inline-formula> 214 <inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> and an output power per unit die area of 662 mW/mm 2 .