AN X-BAND 185° CMOS PHASE SHIFTER MMIC FOR MULTIPLE-ANTENNA SYSTEMS

The design and implementation of an X-band phase shifter MMIC using the standard 0.18-mu m CMOS process is presented. A transformed doublet varactor load is analyzed and applied to a 3-dB quadrature coupler to exhibit large phase shift tuning range and low insertion loss with minimal variation. By using the derived design equations, the implemented CMOS reflection-type phase shifter demonstrates a continuous phase shift tuning range greater than 185 degrees, an average insertion loss of 5.2 dB with perpendicular to 0.4 dB variation, and return losses better than 13 dB in 9-11 GHz. The total chip size including I/O pads is 0.76 x 0.79 mm(2). (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 645-648, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24131