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ABSTRACT: Direct-conversion architectures suffer from the mismatch between the in-phase (I) and the quadrature-phase (Q) branches, commonly called I/Q imbalance. Even low I/Q imbalances imply poor performance of orthogonal frequency division multiplexing (OFDM) systems. In this paper, we propose a new algorithm that uses both training and data symbols in a decision-directed fashion to jointly estimate the channel and compensate for high receiver I/Q imbalance. Simulation results show that our method can compensate for high I/Q imbalance values and also estimate a frequency selective channel.
IEEE Transactions on Communications 06/2009; · 1.68 Impact Factor
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ABSTRACT: This paper describes a 2.4 GHz single-ended switched gain low noise amplifier (SG-LNA) in a 0.35 mum SiGe BiCMOS process. In the design, specific architecture decisions were made in consideration of system-on-chip implementation. The architecture profits from a two cascode stage topology with a shunt resistive feedback in the first cascade-topology stage. The SG-LNA achieved a maximum small signal gain of 34.3 dB within input 1-dB compression point (ICP1dB) of -22 dBm in high-gain mode (HGM), a gain of 25.4 dB within ICP<sub>1dB</sub> of -13.8 dBm in medium-gain mode (MGM) , and a minimum gain of 18.3 dB within ICP<sub>1dB</sub> of -6.8 dBm in low-gain mode (LGM). The noise figures (NF) are 2.9 dB, 5.5 dB and 5.9 dB in HGM, MGM and LGM, respectively. Because of using a Common-Gate topology as an active input matching, the SG-LNA presented a good input and output return losses in all modes. All biases applied are active. The SG-LNA consumes a maximum DC current of 42 mA from a 3.3 volt DC supply.
Advances in Electronics and Micro-electronics, 2008. ENICS '08. International Conference on; 11/2008
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ABSTRACT: A 2.4GHz front-end system design for wide spectrum WLAN applications is presented in a 0.35 μm SiGe BiCMOS Technology. This transceiver front-end contains a receive (Rx) chain with a two-stage cascode low noise amplifier (LNA) and an active down-conversion Rx mixer, and a transmit (Tx) chain composed of a Gilbert-Cell core up-conversion Tx mixer and a high-gain Driver Amplifier (DA). The high linear LNA shows a gain of 15.5 dB, an noise figure (NF) of 2.28 dB and an input- referred third-order intercept point (IP3) of +2.4 dBm with 1-dB gain bandwidth (BW) of 1.5 GHz. The single-balanced Rx mixer exhibited a gain and 1-dB gain BW of +6.8 dB and 1.5 GHz. Also a double-balanced Tx mixer with a gain and input/output return loss of -1.3dB and below -35dB, respectively, and a DA with a gain and output-referred IP3 of +29.2dB and +21.2dBm, respectively, is developed. The NF, input-referred IP3 and DC power consumption of Rx string (from antenna to Rx mixer) were achieved 4.4 dB, -15.4 dBm and 30 mW respectively. The output-referred IP3 and power consumption of Tx chain were +20.5 dBm and 125 mW, respectively.
Information and Communication Technologies: From Theory to Applications, 2008. ICTTA 2008. 3rd International Conference on; 05/2008
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ABSTRACT: This work presents a 14-band low-complexity and high-performance synthesizer architecture for multiband orthogonal frequency-division multiplexing operating in the range of 3.1 to 10.6 GHz. The synthesizer uses a single phase-locked loop with trivial divide-by-2 circuits, single side band mixers, low-complexity filters, and multiplexers. Specifications of the synthesizer components are chosen in order to minimize the total spurs power and respect the IEEE802.15.3a recommendations.
Circuits and Systems II: Express Briefs, IEEE Transactions on 07/2007; · 1.41 Impact Factor
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ABSTRACT: This paper presents the impact of the high-frequency memory of a non-linear amplifier on a multi-carrier (OFDM) transmission and an original, yet very simple, method to compensate for it directly at the transmitter. Our method is efficient thanks to the usage of a long enough cyclic prefix, as in actual OFDM systems.
Communications, 2004 IEEE International Conference on; 07/2004
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ABSTRACT: In this paper, a 1.3 GHz band pass filter, based on a Sallen and Key cell, is presented. A new amplifier topology of the S-K cell is proposed, with input and output differential amplifiers optimized to have high performances in terms of CMMR, IP3 and noise figure. All the filter stages were realized with a SiGe BiCMOS technology. Comparison showed a good agreement between simulation and measurements. In particular, the S-K amplifier gain and the filter selectivity can be tuned. Q factors of up to 60 were measured. The measured even-mode rejection is close to 30 dB at the center frequency.
Radio Frequency Integrated Circuits (RFIC) Symposium, 2004. Digest of Papers. 2004 IEEE; 07/2004
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ABSTRACT: In this paper, a 1.3 GHz Sallen and Key band pass filter, based on a voltage amplifier and designed with an original topology, is presented. This filter realized with a SiGe BiCMOS technology, showed a good agreement between simulation and measurement. In particular, the amplifier gain and the filter selectivity can be tuned. Q factors of up to 60 were measured.
Microwave Conference, 2003. 33rd European; 11/2003
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ABSTRACT: A 1.3-GHz Sallen and Key filter, based on a voltage amplifier designed with an original topology, is presented. SiGe realization showed good agreement between simulation and measurement. In particular, the amplifier gain and the filter selectivity can be tuned and Q factors of up to 60 were measured. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 22–24, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11115
Microwave and Optical Technology Letters 10/2003; 39(1):22 - 24. · 0.62 Impact Factor
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ABSTRACT: This paper deals with the design of microwave analog biquadratic filters using voltage amplifiers. A prototype bandpass filter is monolithically integrated. The chip size is only 1.3 mm2 on GaAs substrate. The filter specifications are: 2Ghz central frequency and a 3dB bandwidth of 40 MHz. A comparison with the SiGe bipolar technology is represented. The circuit represents a building block suitable for use in the cascade realization of higher order filters.
Microwave Conference, 2002. 32nd European; 10/2002
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ABSTRACT: An original method to increase the tuning range of a
monolithic-microwave integrated-circuit (MMIC) varactor diode is
presented in this paper. An active circuit simulating a negative
capacitance is connected to the varactor diode. This method allows to
increase the varactor's tuning range more than ten times and to
compensate its series resistance at the same time. A MMIC simulating a
negative capacitance have been successfully fabricated and measured. To
the best of the authors' knowledge, this is the first realization of a
MMIC simulating a negative capacitance
IEEE Transactions on Microwave Theory and Techniques 01/2002; · 1.85 Impact Factor
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ABSTRACT: We present in this paper a new extraction procedure for MOS transistors. We deal mainly with extrinsic parameters determination, straightforwardly obtained from S-parameters measurements at cold biases (Vds = OV). We apply our procedure to a MOSFET implemented on SOI substrate.
Microwave Conference, 2000. 30th European; 11/2000
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ABSTRACT: SOI devices are frequently used nowadays in the RF and HF field. Design of complex SOI integrated circuits involves a prior detailed analog simulation, that can only be performed through accurate SOI active components models. We are interested here in linear operation modeling; we test new methods for small-signal parameters determination, suitable for a conventional MOSFET high-frequency model and somewhat inspired from methods applied to MESFET technology. In this paper, we deal mainly with extrinsic parameters, for which we obtain reliable estimation on a large frequency range. Our finally adopted extraction procedure takes closely into account the model topology, which reflects the device electrical behavior. We completely describe the procedure, from measurements to the extracted equivalent circuit simulation, without having to optimize parameters and with a straightforward extrinsic elements extraction.
Analog Integrated Circuits and Signal Processing 10/2000; 25(2):157-169. · 0.59 Impact Factor
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ABSTRACT: This paper presents a new method to straightforwardly estimate the
characteristic impedance of transmission lines printed on lossy
substrate, and to accurately model transition between two calibrations.
Other original points consist of the determination of parasitic elements
included in these transitions, and in a clear assessment of the validity
of the results
Microwave Symposium Digest. 2000 IEEE MTT-S International; 02/2000
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ABSTRACT: A new extraction procedure for devices on silicium substrate is presented. This paper deals mainly with a reliable estimation of extrinsic series parameters, which is difficult in MOS transistors due to their isolated gate. This method relies in particular on a judicious on-wafer measurements session.
Microwave Conference, 1999. 29th European; 11/1999
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ABSTRACT: Active filtering has been an area of interest for several years.
Well-stabilised commercial MMIC processes with reasonable costs now
exist (with multichip projects). The authors report the design of a
narrowband active MMIC bandpass filter centred about 4 GHz
Electronics Letters 06/1995; · 0.96 Impact Factor
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ABSTRACT: This paper presents the simulation and measurement results of a broadband MMIC amplifier. This amplifier differs from usual broadband MMIC amplifiers such as resistive matching and those distributed. Its topology is based on the use of active matching and active biasing.
Microwave Conference, 1993. 23rd European; 10/1993
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ABSTRACT: A broadband, lossless microwave active floating inductor is
proposed for general use in a monolithic microwave integrated circuit
(MMIC). The features of this active floating inductor are that: (i) it
is lossless; (ii) it can operate over a wide microwave frequency range;
(iii) its size is independent of the inductance value; and (iv) it can
be easily realized in MMIC
Circuits and Systems, 1993., ISCAS '93, 1993 IEEE International Symposium on; 06/1993
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ABSTRACT: A broadband, lossless microwave active floating inductor is proposed for general use in monolithic microwave integrated circuits. The attractive features of this active floating inductor are that (1) it is lossless, (2) it can operate over a wide microwave frequency range, (3) its size is independent of the inductance value, and (4) it can be easily made using MMIC technology.< >
IEEE Microwave and Guided Wave Letters 05/1993;
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ABSTRACT: An analogue frequency divider implemented with a new GaAs high electron mobility transistor (HEMT) MMIC technology is presented. This frequency divider is based on the frequency regeneration principle. The circuit operates in a frequency division bandwidth of 700 MHz at — I dBm incident input power level around 12.8 GHz. © 1992 John Wiley & Sons, Inc.
Microwave and Optical Technology Letters 12/1992; 5(14):721 - 722. · 0.62 Impact Factor
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ABSTRACT: The measurement of S parameters with a network analyser is affected by both systematic and random errors. Several error models exist for systematic errors. A similar model is proposed to evaluate the random errors which affect the measured values of S parameters when systematic errors have been extracted. This error model is independent of the measured DUT and characterises only the sensitivity of a given calibration procedure to random error. A simulation on a TRL calibration is shown as an example.
Electronics Letters 08/1992; · 0.96 Impact Factor
