Title :
An active differential broad-band phase splitter for quadrature-modulator applications
Author :
Tiiliharju, Esa ; Halonen, Kari A I
Author_Institution :
Electron. Circuit Design Lab., Helsinki Univ. of Technol., Espoo
Abstract :
Area-efficient single-ended-to-differential phase-splitter (balun) integration is difficult for frequencies below 6 GHz. Few broad-band solutions are available, and those given in the literature often introduce quite high amplitude and/or phase errors to differential signaling. In this paper, a cascade of differential pairs is shown always to outperform any single-stage solution, and the measurement data for a two-amplifier prototype are supplied to support the theory. The prototype circuit was realized on 0.8-mum SiGe as a 2.5-V RF integrated circuit measuring 1.2times1.2 mm2 including pads. The measured gain error is better than -1 dB up to 4.6 GHz, while phase difference is between 179.7deg-180.9deg in 0.6-4.1 GHz. The application of the realized phase splitter in a broad-band quadrature modulator is discussed
Keywords :
Ge-Si alloys; baluns; broadband networks; cascade networks; microwave integrated circuits; quadrature amplitude modulation; semiconductor materials; 0.6 to 1.1 GHz; 0.8 micron; 4.6 GHz; GeSi; amplifier prototype; broad-band quadrature modulator; broad-band solutions; differential broad-band phase splitter; differential pairs cascade; gain error; integrated circuit; phase errors; phase sputter; prototype circuit; Gain measurement; Germanium silicon alloys; Impedance matching; Integrated circuit measurements; Phase measurement; Phase modulation; Prototypes; Radio frequency; Radiofrequency integrated circuits; Silicon germanium; Phase splitter; SiGe; quadrature modulator;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2004.840566
