Mon projet de recherche s'applique en premier lieu a developper et adapter les activites sur lesquelles je travaille depuis 14 ans, a savoir la conception et la realisation de circuits (amplificateurs et filtres) micro-ondes pour des applications embarquees sur les repeteurs satellite Pour illustrer cette volonte, j'ai expose deux des themes de recherche (filtres multimodes en bande Ka et amplificateur de puissance a ondes travelling sur substrat silicium), sachant que j'aurai pu egalement evoquer le fait d'appliquer la methode des frequences reelles au traitement des frequences harmoniques pour les amplificateurs fortement non-lineaires de puissance Les autres axes de recherche presentes sont tous dans le domaine de la conception de circuits dits radiofrequences La particularite de ces circuits a application telephonie mobile ou WLAN se situe au niveau des nouvelles techniques de conception qui different de l'approche classique du concepteur analogique ; en effet, elles font souvent intervenir des caracterisations electromagnetiques afin d'extraire des modeles electriques equivalents (balun, resonateur BAW) De plus, la montee en frequence pour certaine des applications RF, autorisant des debits plus grands et donc des bandes passantes plus large (UWB), ou encore les systemes multi-bande et multi-mode (GSM, DCS, PCS WCDMA, bluetooth) necessitent des circuits d'adaptation multi-bande ou large bande dont certains pourront directement s'inspirer des architectures micro-ondes existantes Mon projet de recherche consiste donc a appliquer une approche micro-onde a la conception de circuits integres sur silicium Il ne s'agit evidemment pas de la substituer a l'approche analogique classique, mais au contraire a rendre les deux approches complementaires, afin qu'elles s'en enrichissent

https://tel.archives-ouvertes.fr/tel-00401318/document

Contribution à la Conception de Circuits Microondes et Radiofréquences

Frequency allocations in the L band suitable for global navigation satellite system (GNSS) services are getting crowded and system providers face an ever tougher job when they try to bring in new signals and services while maintaining radio frequency compatibility. With the successive opening of the S and C bands to GNSS service, the multi-band combined navigation is predicted to become a key technology for future high-precision positioning navigation systems, and a single modulation scheme satisfying the requirements in each band is a promising solution for reducing user terminal complexity. A universal modulation scheme based on the continuous phase modulation (CPM) family suitable for the above bands’ demands is proposed. Moreover, this paper has put forward two specific CPM signals for the S and C bands, respectively. Then the proposed modulation schemes, together with existing candidates, are comprehensively evaluated. Simulation results show that the proposed CPM signals can not only satisfy the constraint condition of compatibility in different bands well and reduce user terminal complexity, but also provide superior performance in terms of tracking accuracy, multi-path mitigation and anti-jamming compared to other candidate modulation schemes.

https://www.mdpi.com/1424-8220/15/6/13184/pdf

CPM Signals for Satellite Navigation in the S and C Bands.

RDSS downlink bands, usually with a paired uplink, could be used, like RNSS bands, for satellite navigation. The eventual need for additional Galileo frequencies and signals in S-band or C-band in addition to those currently used is not only about improving the pseudoranging or timing performance, but primarily about introducing new services. Another very important field recently studied to improve accuracy worldwide, is Integer Ambiguity Resolution on Undifferenced Phase which could allow very precise positioning accuracies close to a few cm in real time when permanent phase tracking is maintained on at least two carrier frequencies at the same time. Since cycle slip could occur on a carrier at a given dates, at least 3-carrier tracking is required to ensure robustness for such PPP techniques. In this paper, this last concept of integer ambiguity resolution together with the introduction of new signals/services at S-Band will be studied. The new functions/services specifically provided by a satellite navigation signal at S-band could be also complementary to already existing LEO mobile telecommunication constellations. In this paper it is shown how S-band GNSS signals in addition to the actual L-band signals could also improve the robustness and accuracy, by easing significantly the Integer Ambiguity Resolution on Undifferenced Phase process, combining two fundamental concepts. The first concept introduced in the paper is based on the following finding: if a GNSS system has two signals transmitted at two carrier frequencies that are multiple one of the other, then the wide lane carrier phase ambiguity resolution can be eased a lot. The second concept is the one of “Meta-GNSS signals”. The basic idea consists of processing two different GNSS signals transmitted at different carrier frequencies as a single signal thanks to an AltBOC processing. As it is shown in the paper, these two concepts combined together could therefore allow a robust quasi-centimetric “absolute” positioning, worldwide, thanks to a possible new Galileo signal added at S-band frequencies. The paper details these two concepts and their related area of research, and presents preliminary possible Sband signal designs accordingly.

Toward centimetric positioning thanks to L- and S-Band GNSS and to meta-GNSS signals

With L band frequency allocations for satellite navigation getting more crowded, S band (2483.5–2500 MHz) is already allocated for navigation services, where Globalstar broadcasts downlink communications to user terminals. The Indian Regional Navigation Satellite System (IRNSS) is transmitting navigation signals and Galileo exploits some potential signals in S band. Also, several candidate S band signals based on binary offset carrier (BOC), binary phase shift keying (BPSK), continuous phase modulation (CPM) and minimum shift keying-BOC (MSK-BOC) are suggested for BeiDou system (BDS). In quite narrow S band, mutual interference among these systems is inevitable, thus the compatibility issue is particularly significant for S band signal design. To explore desired S band signals for BDS, the paper firstly describes a comprehensive compatibility evaluation methods based on effective carrier-to-noise ratio degradation for acquisition and code tracking. Then a real simulation is established using space constellations, modulation schemes and received power. Finally, the worst mutual interference of BDS candidate signals with Galileo, IRNSS and Globalstar is calculated and compared. The results indicate that CPM signal is easier to allow peaceful coexistence of other systems with minimal mutual interference in S band compared to other BDS candidates.

Radio Frequency Compatibility Evaluation of S Band Navigation Signals for Future BeiDou.

A direct Ku-band linear subharmonically pumped binary phase-shift keying (BPSK) and in-phase/quadrature (I/Q) vector modulator have been developed using multilayer thin-film multichip module (MCM-D) technology. All passives are integrated in the low cost MCM-D substrate. To the authors knowledge, this is the first modulator based on thin-film integrated passive components. The subharmonic mixing is performed using a beam-lead antiparallel diode pair mounted onto the MCM using thermocompression. A custom diode model has been developed and verified using nonlinear network analyzer measurements: an excellent agreement between the measured and simulated powers and phases for more than nine harmonics is demonstrated. Additionally, it is shown that an optimal reactive termination for the third harmonic of the local oscillator (LO) exists such that a very flat BPSK mixer conversion is obtained. This is validated by measurements that indicate a /spl plusmn/0.25-dB variation on the conversion loss for an LO frequency varying from 6.8 to 7.6 GHz. The I/Q vector modulator consists of a Wilkinson power divider, a coplanar-waveguide Lange coupler, and two BPSK modulators. It has a measured image rejection better than -27 dB over the RF range of 13.4-15.2-GHz band (corresponding to a vector phase and amplitude error lower than 2/spl deg/ and 1%). The image rejection is even better than -32 dB over the very small aperture terminal band (RF: 14-14.5 GHz).

A direct Ku-band linear subharmonically pumped BPSK and I/Q vector modulator in multilayer thin-film MCM-D

Satellite navigation has become such a worldwide priority that many countries are actively deploying or considering their own systems or modernizing those that already exist. As a consequence, the number of signals transmitted in L band will be significantly increased in the next few years so that only scant spectrum will be available for new systems or signals. Since current signals will have to be maintained many years in order to guarantee backward compatibility for legacy receivers, we can foresee that the search for new frequency allocations will be ranked at the highest level with a view to future evolutions of current systems. In this context S-band spectrum between 2483.5 and 2500 MHz, which is already allocated to the radio determination satellite service (RDSS), can be used for satellite navigation - although the allocation in the Radio Regulations is only primary in parts of Asia, Africa and the Americas - is a particularly interesting possibility as synergies with future mobile communication systems in the band immediately above could be exploited to provide both navigation and communication services using one unique S-band terminal with an efficient, common antenna. Only at the next World Radiocommunications Conference in 2012 will the decision be made whether to make the existing patchwork of RDSS allocations global, but the studies completed so far show this to be promising. A global allocation will provide an important opportunity for a worldwide convergence between systems of the mobile satellite service (MSS) and the radio determination/navigation satellite service (RDSS / RNSS). This paper aims to analyze the suitability of this band for navigation purposes as well as the effects that the introduction of these kind of signals would produce on the other radio services present in the same and adjacent bands. We will also present the results obtained from link and error budget calculations and interference assessment that have been performed using various hypothethical of navigation signals in S band. Opportunities for Galileo-2 signals are currently being studied having in mind possible additional frequencies in C and/or S band and/or L band, in complement to the E5a, E5b, E6 and E1 legacy OS, SoL, CS and PRS signals. The paper will give special attention to possible synergies between a hypothetical Galileo-2 S-band signal, IRNSS/GINS and Beidou/COMPASS, which will use L and S bands, other RNSS/RDSS systems and mobile satellite service systems such as GLOBALSTAR-2. These signals will be compared, and synergies between them explored. Several possible waveforms centred on a frequency close to 2491 MHz will be analysed in terms of intersystem interference and in terms of navigation and data transmission performance. The analysed waveforms in Sband will be BPSK(1*1.023 Mcps), BPSK(4*1.023 Mcps), BPSK(8*1.023 Mcps), BOC(1,1) and MBOC.. Power flux density (pfd) and interference computations showing compatibility between a potential Galileo-2 Sband component, S-band GNSS signals, GLOBALSTAR, mobile services (MS) and fixed services (FS) will be presented.

https://hal-enac.archives-ouvertes.fr/hal-01022157/document

Exploration of possible GNSS signals in S-band

This paper presents the design, manufacture and test of a new cold FET monolithic I-Q vector modulator, The circuit has been developed in 8-8.4 GHz X band but can be transposed at any frequency range. The innovation is that the IF data signals are applied to the FET gates. The use of cold FETs allows achieving a 0.8 dB and 6° accuracy with only one voltage tuning on the whole bandwidth and the ?25°C to +50°C temperature range. There is no DC consumption for the microwave modulator, The accuracy achieved at this first run is yet compatible with new coding and modulating systems and we have investigated several ways to improve the design.

/pdf/new-cold-fet-i-q-linear-vector-modulator-topology-190c1nzswv.pdf

New Cold FET I-Q Linear Vector Modulator Topology

We present a new topology of 8 Phase Shift Keying modulator that allows achieving a very high accuracy of 0.4dB and 3° on the 8-8.4 GHz band in the ?10°C to +55°C temperature range, with only one tuning voltage and a very low consumption. The device has been manufactured on the D02AH OMMIC GaAs PHEMT process but has been transposed to other FET foundries. This new topology is covered by a patent [1]. It has been transfered and improved by Alcatel Space Industries, to fit industrial quality requirements, in order to define a commercial product of high data rate transmission channel for micro-satellites.

X Band MMIC direct 8 Phase Shift Keying modulator for high data rate earth observation applicaions

Conception d amplificateurs de puissance à l aide de la méthode des fréquences réelles

The invention concerns a method and a circuit for analogue phase and/or amplitude modulation of a high frequency carrier signal with an I or Q low frequency analogue modulation signal, comprising at a least mixer stage (5, 6) including two field-effect transistor, called modulation transistors (21, 22), mounted with the sources (23, 24) jointly connected to ground, and whereof the drains (25, 26) are not polarised. The method consists in applying on the gates (30, 31) of the modulation transistors (21, 22) I or Q modulating analog electric signals, I or Q at low frequency matching each other, whereof the amplitude is less than a maximum value Amax beyond which the power of the signal modulated in output is no longer proportional to the power of the modulating signal.

Cyrille Boulanger

Papers

Exploration of possible GNSS signals in S-band

New Cold FET I-Q Linear Vector Modulator Topology

X Band MMIC direct 8 Phase Shift Keying modulator for high data rate earth observation applicaions

Conception d amplificateurs de puissance à l aide de la méthode des fréquences réelles

Method for analog modulation and monolithic integrated circuit mixer stage comprising transistors has not polarized field effect