Marko Krcmar

Local Positioning for Wireless Sensor Networks

This workshop paper gives an overview of local positioning and tracking principles for wireless sensor networks including recent results of the European project RESOLUTION (reconfigurable systems for mobile local communication and positioning). Measurements of a first demonstrator applying a frequency modulated continuous wave (FMCW) radar principle are presented. The unlicensed ISM band around 5.8 GHz, 150 MHz bandwidth and less than 25 mW effective isotropic radiated transmit power are used. Excellent 3-D positioning accuracies in the order of 4 cm in an anechoic chamber and 18 cm in a conference hall with strong multipath and area of 800 m2 are measured. Furthermore, the results of optimized radio frequency integrated circuits and a suitable compact flash card are outlined.

A Broadband Folded Gilbert-Cell CMOS Mixer

A folded Gilbert cell mixer has been implemented in a 0.13 mum CMOS technology. RF- and IF- frequencies of the down conversion mixer were 5.5 GHz and 500 MHz, respectively. A power conversion gain of 4.6 dB and a noise figure of 14.2 dB have been demonstrated experimentally under very low power consumption, only 4.2 mW for the mixer core. Considering the overall performances of the circuit, this paper shows that the folded mixer architecture is one of the most interesting frequency converter solutions for low-power mobile applications.

A High Performance Low IF Receiver for Wireless Local Positioning Applications

This work demonstrates an integrated low noise, high gain receiver targeted for wireless local positioning applications. The receiver is implemented in a 0.18 mum SiGe BiCMOS technology. With a single ended input and differential output the receiver comprises a two stage bipolar low noise amplifier with integrated on-chip transformer for single to differential conversion and a double balanced mixer based on folded Gilbert cell architecture. The LNA and mixer circuits are integrated through wire bonding. According to the system frequency planning, RF and IF frequency bands of the receiver are 5.725 GHz to 5.875 GHz and 500 kHz to 5 MHz. At 5.8 GHz RF and 5 MHz IF, the integrated receiver performance comprise 28 dB power gain, 34 dB voltage gain, 2.3 dB noise figure, -30 dBm of input power at 1 dB gain compression and -24 dBm input third order intercept point. The low noise and high gain performance of the proposed receiver topology makes it to be an optimum choice for the targeted local positioning application based on frequency modulated continuous wave (FMCW) radar.

Low noise BiCMOS receiver for FMCW radar positioning systems

In this work we present a fully integrated BiCMOS RF-receiver. The receiver comprises an LNA and a mixer. The most challenging aspects of the design were the high gain and an extremely low noise figure specified by RESOLUTION. The target was to achieve an integrated LNA and mixer showing at least 25 dB voltage conversion gain and overall noise figure less than 4 dB under minimum power consumption. A low IF architecture is requested converting the RF signal between 5.725 GHz and 5.875 GHz to a 500 kHz - 5 MHz IF band. This article is organized as follows: first we will present the details of the circuit design discussing the architecture and design techniques; following this the experimental results of the receiver will be presented and finally, we will discuss the results with respect to the RESOLUTION system specifications.

High performance CMOS receiver for local positioning systems

A fully integrated CMOS receiver consisting of an LNA and a mixer has been designed and fabricated in IBM BiCMOS 7WL 180 nm technology. An on-chip balun loading the second stage of the LNA was implemented as well for single-to-differential conversion. The receiver was developed for high performance wireless local positioning systems and excellent experimental results were demonstrated: a conversion gain (CG) of 28 dB, a low noise figure (NF) value of 3.3 dB and an input third order intercept point (IIP3) of − 11.5 dBm while consuming only 50 mW. The low noise, high gain and very high linearity performance of the proposed receiver topology makes it to be an optimum choice for the targeted local positioning application based on frequency modulated continuous wave (FMCW) radar.

Digitally Controlled VGA for Low Power Low-IF Receivers

A digitally controlled variable gain amplifier (VGA) for low power, low-IF receivers is presented. The amplifier was designed and fabricated in IBM 7WL BiCMOS 180 nm technology. It shows a dynamic range of 45 dB with a maximum gain of 52 dB and a minimum gain of 7 dB. The gain variation is achieved by means of switched feedback resistors. These are controlled by a demultiplexer and 4 control bits. The 1 dB compression corresponds to 9 dBm of input power in a 50 ¿ system and the 3-dB-bandwith is approximately 10 MHz. The overall power consumption is 13 mW.