Local positioning will be one of the most exciting features of the next generation of wireless systems. Completely new concepts and features for wireless data transmission and transponder systems will emerge. Self-organizing sensor networks, ubiquitous computing, location sensitive billing, context dependent information services, tracking and guiding are only some of the numerous possible application areas. This article introduces different concepts of several existing and emerging systems and applications.

Wireless local positioning

A low voltage multiband all-pMOS VCO was fabricated in a 0.18-/spl mu/m CMOS process. By using a combination of inductor and capacitor switching, four band (2.4, 2.5, 4.7, and 5 GHz) operation was realized using a single VCO. The VCO with an 1-V power supply has phase noises at 1-MHz offset from a 4.7-GHz carrier of -126 dBc/Hz and -134 dBc/Hz from a 2.4-GHz carrier. The VCO consumes 4.6 mW at 2.4 and 2.5 GHz, and 6 mW at 4.7 and 5 GHz, respectively. At 4.7 GHz, the VCO also achieves -80 dBc/Hz phase noise at 10-kHz offset with 2 mW power consumption.

A low-phase-noise and low-power multiband CMOS voltage-controlled oscillator

Compact miniaturized hairpin resonators are used to design cross-coupled filters with a dual-passband response of elliptic function type. The hairpin resonators are treated as a stepped impedance resonator (SIR) in analysis. In a filter, two different hairpin resonators are used to establish proper couplings required for the two design frequencies. Two filters are fabricated and measured. The results show a good agreement with the simulation.

https://ir.nctu.edu.tw:443/bitstream/11536/26342/1/000224278800006.pdf

Design of quasi-elliptic function filters with a dual-passband response

A dual-band trimode radio fully compliant with the IEEE 802.11a, b, and g standards is implemented in a 0.18-/spl mu/m CMOS process and packaged in a 48-pin QFN package. The transceiver achieves a receiver noise figure of 4.9/5.6 dB for the 2.4-GHz/5-GHz bands, respectively, and a transmit error vector magnitude (EVM) of 2.5% for both bands. The transmit output power is digitally controlled, allowing per-packet power control as required by the forthcoming 802.11 h standard. A quadrature accuracy of 0.3/spl deg/ in phase and 0.05 dB in amplitude is achieved through careful analysis and design of the I/Q generation parts of the local oscillator. The local oscillators achieve a total integrated phase noise of better than -34 dBc. Compatibility with multiple baseband chips is ensured by flexible interfaces toward the A/D and D/A converters, as well as a calibration scheme not requiring any baseband support. The chip passes /spl plusmn/2 kV human body model ESD testing on all pins, including the RF pins. The total die area is 12 mm/sup 2/. The power consumption is 207 mW in the receive mode and 247 mW in the transmit mode using a 1.8-V supply.

/pdf/a-single-chip-cmos-transceiver-for-802-11a-b-g-wireless-lans-3caa7qopb7.pdf

A single-chip CMOS transceiver for 802.11a/b/g wireless LANs

An oscillator with a high-order (>2) resonator has multiple stable modes of oscillations. The stable modes for one such oscillator, having a fourth-order resonator, are found using a nonlinear analysis. By using a proper nonlinear active topology and tank component values, the fourth-order oscillator can generate either of the two distinct frequencies f1 or f2. A method is introduced to dynamically switch between the stable modes of oscillations. It is shown that the phase noise of this fourth-order oscillator, when generating only one of its resonant frequencies, is comparable to the phase noise of a second-order oscillator using the same active topology and resonator quality factor. Furthermore, the fourth-order oscillator has better phase noise and/or higher tuning range in VCO implementations compared to the commonly used switched resonator oscillators. The claims have been verified experimentally through an integrated oscillator prototype with f1 = 2.4 GHz and f2 = 4.7 GHz fabricated in a standard 0.18 mum CMOS technology. The oscillator draws 1.89 mA current of 1.8 V supply. The 1 MHz offset phase noises of the fourth-order oscillator for f1 = 2.4 GHz and f2 = 4.7 GHz are -122.4 dBc/Hz and -123.4 dBc/Hz, respectively.

Frequency Switching in Dual-Resonance Oscillators

A fully monolithic dual-band radio transceiver chip for 802.11a, 802.11b and 802.11g applications is presented in a 0.25 /spl mu/m 40 GHz BiCMOS technology. The transceiver chip contains a complete receiver chain with low noise amplifier, mixer, programmable gain amplifier, CCK and OFDM channel filters. In the transmit path, a direct-modulation transmitter with integrated anti aliasing filters and programmable gain control is implemented. The frequency synthesizer consists of a fully integrated VCO, a reference oscillator and a phase locked loop for both supported frequency bands of 2.4 GHz and 5 GHz. For a 3 V power supply, the overall power consumption for 802.11a receive-mode and transmit-mode are 600 mW and 450 mW, respectively.

M. Punzenberger

Papers

5-GHz and 2.4-GHz dual-band RF-transceiver for WLAN 802.11a/b/g applications