This letter presents the design and implementation of a differential Ka-band variable gain low noise amplifier (VG-LNA) with low insertion phase imbalance. The VG-LNA is based on a 0.12 μm SiGe heterojunction bipolar transistor process, and the gain variation is achieved using bias current steering. The measured VG-LNA gain at 32-34 GHz is 9-20 dB with eight different linear-in-magnitude gain states, and with a noise figure of 3.4-4.3 dB. The measured rms phase imbalance is < 2.5° at 26-40 GHz for all gain states and this is achieved using a novel compensating resistor in the bias network. The VG-LNA consumes 33 mW (13.5 mA, 2.5 V) and the input 1-dB gain compression point is -27 dBm. The chip size is 0.13 mm2 without pads.
Bibliographical noteFunding Information:
Manuscript received October 19, 2007; revised December 5, 2007. This work was supported by the U.S. Army Research Lab. under the CTA effort. B-W. Min is with the Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 49109 USA (e-mail:firstname.lastname@example.org). G. M. Rebeiz is with the Electrical and Computer Engineering, University of California, San Diego, CA 92093 USA (e-mail:email@example.com). Digital Object Identifier 10.1109/LMWC.2008.918917 Fig. 1. Basic types of VGA: (a) bias control, (b) feedback control, and (c) current splitting.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Electrical and Electronic Engineering