Antoine Diet

Architecture and filtering requirements for fully digital multi-radio transmitters

This paper gives filtering requirements for an all-digital transmitter and identifies technical and technological challenges. Herein, we highlight trade-offs implied by such a transmitter. This work targets a flexible and low power consumption transmitter, taking into account advantages of sub-micron CMOS technologies. We focused on a multi-radio transmitter for cellular standards such as GSM, WCDMA and LTE for mobile applications. Simulation results point out the mandatory frequency replicas management caused by up-sampling process and the so needed filtering before emission to be dimensioned. Specifications of the filter to be design are given after an overall fully digital architectures study.

Microstrip band pass filter bank for 60 GHz UWB impulse radio multi band architectures

This paper demonstrates the potentiality of second order microstrip coupled lines bank filters approach for 60 GHz UWB impulse radio multi band architectures. Two band pass filters banks were designed, simulated and optimized using Agilent software HPADS. Filters characteristics and their influence on the transceiver performances are discussed.

A UWB micro-strip antenna design and simulation

We are concerned, herein, with the conception and the design of printed UWB antennas and with the analysis of their performances through figures of merit. State of the art gives the opportunity to exploit some empirical considerations about the shape and the methodology of conception. A simple structure is simulated by means of CST microwave studio to show the possibility of fulfilling, at a defined level, UWB antenna requirements such as matching, fidelity and quasi-isotropy of the radiation pattern with a simple micro-strip design and a standard technology

Flexibility of class E HPA for cognitive multi-radio architecture

This paper consists in the analysis and simulation of two topologies of high efficiency power amplifier (HPA) in the context of the cognitive multi-radio architecture. More precisely, the goal is to study the possibility of front-end radio standards flexibility using a class E HPA. Two main topologies are studied, serial and parallel, and simulations under ADS software are performed in order to validate the proposed tuning of the HPA. Results encourage possibilities of providing efficient and constant power amplification from almost 1 to 5 GHz.

Front end accordability for cognitive multi-radio, using a class E HPA and a multi-band antenna

In this paper, it has been demonstrated the possibility of frequency discrete shifting with a class E high efficiency PA, simulated with a realistic E-PHEMT model and co-simulated with antenna measures for the load. Antennas loads influence the PA performances because of their wideband characteristic and not only their adaptation at the carrier frequency. This implies a very precise measurement of antenna reflection coefficient for PA co-design. At these frequencies, the transistor packaging can destroy the Class E performance before the loading. Switched PA will show closer performance between simulations and measures if the design is first integrated (longer and costly design). That is why the front end measures are not available yet. Results enable to go further in the methodology of joint-conception between an antenna and a PA for multi-radio. This type of co-design topic demonstrated that in wideband systems, multi-disciplinarity is essential for accurate behaviour of the front-end and performances can target a high efficiency (more than 70 % for the moment) front end in the multi-radio considered bandwidth.

Technological locks for 60 GHz high data rate Impulse Radio Multi-band OOK front end, with channel effect consideration

This paper concerns the potentiality of 60 GHz Impulse Radio (IR) Multi-band On Off Keying (IR-MBOOK) transceivers architectures with non-coherent energy detection for high data rate and low power consumption 60 GHz applications. Such architectures require band filter bank at both transmission (Tx) and reception (Rx). The difficulty to design such blocks at these frequencies (technology of the filters for example) strongly impacts the radio link performances. The context of the study is to analyze the communication system in dispersive indoor channel, taking into account antennas and propagation additional effects. The study focuses, herein, on a four bands filter bank, which exhibits a maximum insertion loss (IL) of 3.5 dB and a relative bandwidth of 2,7%. A microstrip printed antenna was designed and simulated, considering specifications of indoor applications, such as kiosk downloading or very high speed wireless connections. Simulations of the radio link with a filter bank design and incorporating antennas and propagation effects in different scenarii are presented and confirm the interest of the proposed solution.

New figures of merit qualifying devices and amplifiers, operating in switched mode

In the context of mobile communication and connectivity system evolution, new transmitter architectures should be studied in order to design nomadic multiradio low consumption transceiver. In term of efficiency, the most important element is the amplifier. In order to obtain high efficiency performance, it is possible to use several architectures associated with switched amplifier. In this paper, we propose different figures of merit established from DC characteristics of a device used in switched mode. We confirmed the validity of this methodology by designing several class E amplifiers using P-HEMT depletion transistor. And, we propose a representation of the device potential by using the performance factor.

On the links between peak to average power ratio for conventional RF power amplifiers and peak to average duration ratio for switching mode power amplifiers

For conventional RF power amplifier (PA), the power efficiency depends on the peak to average power ratio (PAPR) of the input signal, or more precisely on the statistical distribution of the input signal amplitude. In this paper we show that, in a similar way, the power efficiency of switching mode PA driven by ΣΔ or PWM signals depends on the statistical distribution of input signal the states and on a parameter equal to the Peak to Average Duration Ratio. This parameter is related to the PAPR in a way depending on the type of encoding of PA input signals.

A RF TX low insertion loss reconfigurable bandpass filter based on highly linear 65nm CMOS active inductors for cellular applications

This paper presents the design and implementation of a bandpass filter with very low insertion losses (<0.5dB) for cellular transmitters, with 0dBm capabilities. In order to obtain a high integration of the filter with existing fully digital architectures, it has been designed in CMOS 65nm technology. This filter takes full advantage of previously developed highly linear and high Q active inductors in CMOS. We present a design methodology based on filter frequency reconfigurability (1.72.1GHz) while preserving linearity and low insertion losses on this wide frequency range.