WCDMA Channels Research Articles

Explicit design of remote‐tuned combiner for GSM and WCDMA signals

AbstractThe problems associated with combining multiple GSM carriers and WCDMA signals onto a single antenna are developed leading to a unique solution. This solution is based upon the concept of cascading directional filters to meet the electrical requirements, which may readily be tuned electrically leading to remote‐tuned products capable of injecting one or more WCDMA channels into the same communication band as several GSM carriers.A particular solution is presented, which exhibits both optimum amplitude and group delay characteristics for the WCDMA signal. Closed‐form expressions are given for the network functions including the amplitude and group delay characteristics. By developing techniques similar to those used in Rhodes (Theory of Electrical Filters. Wiley: New York, 1976), explicit formulas for element values in the general 2nth degree network are given and proved.A practical operating unit for the US cellular band has been designed and constructed. Measured per‐ formance is given and shows excellent agreement with theory. Copyright © 2007 John Wiley & Sons, Ltd.

Programmable SiGe BiCMOS low-pass filter for a multicarrier WCDMA base-station receiver

SiGe BiCMOS low-pass filter for a multicarrier WCDMA base-station receiver is described in this paper. The 4th-order Chebyshev filter with a 0.1-dB passband ripple is designed to drive a high-resolution A/D converter. The ?3-dB frequency of the implemented filter can be programmed to four different bandwidths: 2.5, 5, 7.5, and 10 MHz depending on the number of received WCDMA channels. The filter achieves +9.7-dBV in-band IIP3, +20-dBV out-of-band IIP3, and 8.5-nV/?Hz input-referred noise density with 10-MHz bandwidth. The circuit uses a 2.5 V supply and has been fabricated in a 0.25-μm SiGe BiCMOS process.

WCDMA Multicarrier Receiver for Base-Station Applications

The multicarrier receiver IC described in this paper receives four adjacent WCDMA channels simultaneously in order to reduce the component count of a base-station. The receiver uses low-IF architecture and it is fabricated with a 0.25-mum SiGe BiCMOS process to meet the high-performance requirements set by the base-station application. The receiver includes a dual-input low-noise amplifier (LNA), quadrature mixers, a local-oscillator (LO) divider, IIP2 calibration circuits, 10-MHz low-pass filters, and ADC buffers. The receiver noise figures, measured over the downconverted WCDMA channels centered at 2.5-MHz and 7.5-MHz intermediate frequencies, are 3.0 dB and 2.6 dB, respectively. The receiver achieves 47-dB voltage gain and -12-dBm out-of-band IIP3 and consumes 535mW from a 2.5-V supply