Table of Contents
International Journal of Microwave Science and Technology
Volume 2007, Article ID 47927, 8 pages
Research Article

An Integrated 5 GHz Wideband Quadrature Modem for OFDM Gbit/s Transmission in SiGe:C BiCMOS

IHP-microelectronics, Im Technoloiepark 25, Frankfurt D-15236, Germany

Received 25 January 2007; Revised 23 April 2007; Accepted 3 August 2007

Academic Editor: Kenjiro Nishikawa

Copyright © 2007 Klaus Schmalz et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper presents a 5 GHz wideband I/Q modulator/demodulator for 650 MHz OFDM signal bandwidth, which is integrated with a 5 GHz phase locked loop for I/Q generation. The quadrature signals are derived from a 10 GHz CMOS VCO followed by a bipolar frequency divider. The phase noise at 1 MHz offset is 112 dBc/Hz for the modulator as well as for the demodulator. The chips were produced in a 0.25 μm SiGe BiCMOS technology. The signal-to-noise ratio (SNR) of transmitted/received OFDM signal and the corresponding I/Q mismatch versus baseband frequency are given. The modulator achieves an SNR of 22–23 dB, and the demodulator realizes an SNR up to 22 dB. The modulator reaches a data rate of 2.16 Gbit/s using 64 QAM OFDM, and the demodulator realizes 1.92 Gbits/s.