Nooshin D. Vakilian

An integrated closed-loop polar transmitter with saturation prevention and low-IF receiver for quad-band GPRS/EDGE

This paper describes a 2.5G cellular transceiver with standard DigRF interface, implemented in a low-cost 0.13µm CMOS process. This is the first CMOS single-chip, polar closed-loop transmitter, excluding the power amplifier (PA). This transmitter achieves an efficiency of 26% in EDGE mode by linearizing a saturated PA in a closed-loop feedback system. This is much higher than the typical 15-to-18% efficiency of systems using a linear PA [1]. Typical high-band/ low-band performance of −62/−64dBc in 30kHz for 400kHz offset spectral mask and 1.4/1.7% EVM in EDGE mode are significantly better than those reported earlier [1–3]. Using a low-noise quadrature mixer topology, the receiver, including T/R switch and SAW filters, achieves a sensitivity of −110dBm. The RF solution, consisting of PAs in a multi-chip integrated antenna switch module, SAW filters with integrated matching components and the transceiver, shown in Fig. 6.1.1, is the smallest form factor available in the market today.

A triple-band 900/1800/1900 MHz low-power image-reject front-end for GSM

Conventional cellular handset receiver designs place receive-band filters, usually surface acoustic wave (SAW) filters, prior to and after the low-noise amplifier (LNA). In a triple-band receiver, this amounts to six SAW filters. The device presented here also eliminates the post-LNA SAW filters, but without the excess current required by image-reject mixers. It does so through the use of passive on-chip LC image filters. This makes possible higher dynamic range with low supply current, and low noise figure while providing a greater amount of image-rejection in comparison with image-reject mixer-based solutions.

Architecture and performance overview of a highly integrated 13/spl times/13 mm Single-Package Radio (SPR) module for dualband EGSM900/GSM1800 applications

The RF system architecture and the performance overview for a very highly-integrated Single Package Radio (SPR) module for dual-band EGSM900/GSM1800 applications is presented. The module realizes all the RF functions required for the dual-band GSM application. These functions as well as their implementations are described. The integrated LO generation consists of reference oscillator circuitry, a UHF oscillator, and delta-sigma fractional-N synthesizer. The receiver is based on a direct-conversion (zero-IF) architecture with the front-end selectivity performed by the two integrated SAW filters. The transmitter is comprised of an upconversion-loop transmit chain with two high-power transmit oscillators, a dual-band power amplifier, detector-based transmit power control, transmit/receive switch, duplex filter and all other necessary filters. Diverse die technologies are utilized to apply the optimum process for each function. The SPR module is implemented on a low cost 4-layer laminate substrate and overall dimensions are 13/spl times/13/spl times/1.8 mm. Measured results against GSM specifications are presented.