Objectives

The objective of the activity is to develop and test a scalable, generic and reconfigurable multibeam receive antenna architecture for feeder links, operating in V-band and supporting high-capacity, geostationary, broadband multimedia missions.

Challenges

The challenge of the project is the replacement of multiple (typically four or more) feeder link reflector antennas by a single antenna.

System Architecture

In order to assess the potential product features, various types of antenna architectures are part of the trade-off:

1. active phased arrays magnified by reflector(s);
2. active phased arrays;
3. discrete lens antennas.

Suitable active components (LNA) identification, Beam-forming networks (BFN) typology, mass, volume, dimensions, complexity, thermal management, operational/ environmental constraints are the subjects to be optimised.

Plan

GRETA contract started on 01.03.2024. Expected project duration is 24 months.

The following project milestones are considered within the overall project development:

• KoM – Kick-Off Meeting;
• SRR – System Requirements Review;
• PDR – Preliminary Design Review;
• CDR – Detailed Design Review;
• TRR – Test Readiness Review;
• TRB – Team Review Board;
• FR – Final Review.

Current Status

The project’s PDR has been achieved.

Companies

ST4I – Space Technologies for Innovation

https://www.st4in.com

Italy

Thales Alenia Space Italia

https://www.thalesgroup.com/en/worldwide/space-italy

Italy

NHOE

https://www.nhoe.it/

Italy

Objectives

The objective of PHOTON-MIX is the development of a high-port-count, low-mass-and-energy-consumption, fast switch matrix for optical communications in the C-band. The enabling technologies to address simultaneously all these requirements are integrated photonics and latching bistable MEMS switches. The former allows to concentrate a great number of optical devices in a cm-sized silicon microchip, thus providing high number of channels and compactness: low size and weight. The latter make it possible to set the state of each of the switch of the matrix either ON or OFF without the need of maintaining a voltage applied constantly to fix this state: this accounts for low power consumption.

Challenges

The key challenges of this project include the demonstration of the MEMS latching mechanism, the development of a reliable microfabrication process flow, the development of a dedicated driving electronics board, and the assembly including all mechanical support structures and electrical and optical interfaces.

System Architecture

The general architecture has been consolidated with some preliminary analysis assessment for the thermos-mechanical and mechanical analysis. The functionality of the bias matrix was successfully demonstrated with some optimisation performed during the switch matrix test. The electronics design offers the required flexibility. Not all verification could be implemented due to project time line and budget. However, the critical aspects of the design have been tested.

Plan

The requirements have been consolidated shortly after Kick-off which enable the launch of LLI procurement and the start of preliminary design activities. Critical design aspects of the preliminary design have been bread boarded and tested. Their results were assessed during the Critical Bread boarding Test Review allowing to carry on with the Demonstration Model (DM) design activities. After finalisation of the MEMs design materialised by the Detailed Design Review, the manufacturing of the DM was released. Testing on the DM was performed following successful TRR, results and associated documentation (product roadmap) were evaluated during the Final Review.

Current Status

The non-volatile MEMS design based on optical switch matrix is available. The fabrication process implemented at EPFL clean room facilities and based on DUV lithography compatible with foundry process has been validated. The non-volatile MEMs switch has been integrated into a modular unit named DM, fully packaged and easy to use. The operational functionality (optical & electrical) of a MEMs switch was fully verified in a lab environment allowing to reach TRL 4.

Related Links

• SPIE Conference Presentation on Bistable Silicon Photonic MEMS Switches.

Companies

EPFL - École Polytechnique e Fédérale de Lausanne

http://www.epfl.ch

Switzerland

Thales Alenia Space Switzerland

https://www.thalesgroup.com/en/europe/switzerland

Switzerland

Objectives

The main objective of this activity is to enable inter-satellite communication link at 5000 km distance and with up to 10 Gbps capacity. In order to achieve the required data rate and link length, the main technical objective is to increase both the bandwidth and the transmitted power. In the first case, a greater bandwidth availability allows the use of wider frequency channels. In the second case, the idea is to allow the use of higher-order modulations, increasing the number of bits per symbol. The overall result derived from the combination of these two approaches allows to reach the target requirements. This PA is able to provide 10W of output power measured at P1dB over the whole 59-71 GHz frequency band ensuring enough power and linearity to enable communication link up to 5000 km with enough linearity to work with highly complex modulated signals. In Fig 1 the whole amplifier, in Fig 2 a single PA module. 

Challenges

This project combines three challenging requirements: high output power at high frequency and over wide bandwidth. GaN/SiC processes are able to provide high output power with sufficient gain at V-band, but the required value of P1dB cannot be achieved with a single device. The high power amplifier combines 8 GaN module in a waveguide structure. To minimize the risks involved with this project two different PA have been designed and manufactured using two different GaN processes from Fraunhofer (0.1µm and 0.15µm gate length), moreover transistor model accuracy and device reliability have been evaluated by University of Ferrara.

System Architecture

The required output power of 10 W at V-band cannot be achieved using a single device with current IC technology. 8 modules are combined to reach the specified power: this is a trade off because increasing the number of elements determines an increased loss and complexity of the output network. The modules number is a consequence of the available power from a single device that is about 33 dBm and the estimated loss of the network that is below 1 dB. Different option were available to realize the combination network: the final selected solution relies on a standard WR15 metallic hollow waveguide branching with three binary levels of H-plane tees. The choice of avoiding balancing resistors guarantees the best insertion loss and lower manufacturing complexity. Furthermore, the planar architecture selected leaves a completely flat surface on the back to ease heat dissipation.

The selected technology for PA is a 0.1 µm GaN/SiC from Fraunhofer, fT/ fMAX are 80 GHz and 200 GHz respectively, with output power up to 2W/mm. Monolithic amplifier is based on a Doherty architecture to have higher P1dB and PAE. In Fig 1 the schematic architecture and in Fig. 2 a 3D model of the amplifier.

Plan

The specification of the front-end HPA (High Power Amplifier) are derived from the ones given by ESA for the full Solid State Power Amplifier. The first activity in the plan is design of the Critical Elements as integrated circuits, combiner/splitter, the transition between MS line and waveguide. Test of these elements follows: any deviation from expected results should be analysed to evaluate its impact on overall performances, eventually the part should be re-designed. When critical elements performances are satisfactory, the HPA can be assembled and fully tested. 

Current Status

Project has been completed with the manufacturing and test of a High Power Amplifier realized using integrated circuits on 0.1µm Ga/SiC process. Measurements demonstrates an output power of 10 W at P1dB over the whole frequency band, the small signal gain is 23 dB.

Related Links

• SIAE microelettronica
• Università degli Studi di Ferrara – Dipartimento di Ingegneria
• Open acces paper: “GaN/SiC V-band 10 W high-power amplifier for inter-satellite communications”

Companies

SIAE Microelettronica Spa

http://www.siaemic.com

Italy

Università di Ferrara - Dipartimento di Ingegneria

https://de.unife.it/it/ricerca-1/laboratori-di-ricerca/etlab

Italy

Objectives

The project objectives are to design, manufacture and test a Ka-to W-band frequency up-converter for use as a payload component in high-capacity feeder link systems. European state-of-art MMIC technologies are used for the development of the functional blocks. Superior performances, ideally at the level of the current lower frequency converters, are sought, in order to guarantee the quality of the signal operating in W-band. 

The following tasks are covered by the project:

a) Development of 6 new typologies of MMICs by using the UMS-PH10 foundry process: 1) 27-30 to 71-76 GHz up-converter mixer, employing a sub-harmonic topology; 2) same up-converter mixer also including a by-two frequency multiplier in the LO RF line, in order to enter the LO port at around 10 GHz; 3) Standalone by-two frequency multiplier; 4) 71-76 GHz Voltage Variable Attenuator (VVA); 5) 71-76 GHz Low Level Amplifier (LLA); 6) 71-76 GHz Medium Level Amplifier (MLA). 

b) Development of the hermetic mechanical module housing the above circuits.

c) Development of the hermetic waveguide-to-microstrip transition in W-band.

d) Development of the output W-band waveguide filter 

f) Assembly and Test of the individual functional blocks 

g) Assembly and test of the whole Up-converter unit

Challenges

The main challenge is the design of the MMICs operating in W-band, as the PDK given by the foundry is poorly guaranteed above 60 GHz. In addition, the design of the waveguide-to-microstrip transition is particularly critical from an electrical and technological standpoint, as the size is very small. Also, the waveguide filter is found challenging for manufacturing tolerances and surface roughness. 

System Architecture

The RF line-up of the Frequency Converter is composed by the following functional blocks:

1) Hermetic coax-to-microstrip transition

2) Up-converter mixer MMIC

3) LLA MMIC

4) Microstrip flatness equalizer

5) VVA MMIC

6) LLA MMIC

7) MLA MMIC

8) Microstrip-to-waveguide hermetic transition

9) Waveguide filter 

A conventional board is included in the module performing temperature compensation of the gain and conditioning the supply voltages.

Plan

• Baseline specification

• Critical Element design

  Milestone: PDR

• Critical Elements MFG & test

  Milestone: CDR

• RF line-up design

  Milestone: DDR

• RF line-up MFG & test

  Milestone: TRB MMIC

  Milestone: TRB unit

• Overall evaluation

  Milestone: FR

Current Status

The tasks accomplished up to now are listed below:

• Baseline specification                       completed 

• Critical Element design                     completed

  Milestone: PDR                      passed

• Critical Elements MFG & test           completed

  Milestone: CDR                     passed

• RF line-up design                             completed 

  Milestone: DDR                     passed

• RF line-up MFG & test                     in progress

  Milestone: TRB MMIC

  Milestone: TRB unit

• Overall evaluation

  Milestone: FR

Companies

Thales Alenia Space Italia

https://www.thalesgroup.com/en/worldwide/space-italy

Italy

MEC - Microwave Electronics for Communications

http://www.mec-mmic.com

Italy

Objectives

The objective of this activity is to design and develop a high voltage power transformer in planar technology for Electronic Power Conditioning Units (EPC) used to drive travelling wave tubes.

The aim is to develop a novel transformer design solution not existing today in Europe for up to 8kV class of EPCs (with research of margin up to 10kV). 

A transformer engineering model is designed, manufactured and tested in a  representative environment to validate the developed concept for space application.

The main intermediate objectives of this project are: 

• To establish a detailed requirement specification for the high voltage planar transformer,

• To define a program (in Excel), based on the build-up in order to compute the tracks size of primary and secondary windings, the leakage inductance, the copper losses of the secondary and primary windings, the core losses, the resonant push-pull losses and rectifier losses,

• To define thermal and electrical models of the High Voltage Planar technology,

• To review and de-risk the available technologies and processes available in accordance with the technical requirements defined,

• To minimise the manufacturing complexity and to ease flexibility during production aiming at a short time to delivery.

Challenges

The main technological challenges are the management of the high electrical fields inside the planar transformer assembly, and the thermal management of the transformer.

The chosen design needs to manage high voltage design rules in PCBs, while at the same time using a more complex build-up than high voltage PCBs currently used.

Thermal design needs to be optimized by using innovating solutions such as optimizing the transformer build-up and improving thermal interfaces with the structure.

System Architecture

Resonant transformer topology working at high frequency.

The Planar transformer technology is based on a high voltage multilayer PCB equipped with its ferrites, thermal conductive material and mechanical fixations.

The secondary side is a single or multiple windings and the primary side is a push-pull type so double windings with a common point.

Plan

The project’s work plan is based on the following methodology:

1. Based on the state of the art of the Travelling Wave Tube Amplifier, to build the definition of a detailed technical requirement specifications for planar transformer,

2. To study suitable technologies to achieve a high voltage transformer in planar technology based on a technical trade-off and specific de-risking evaluation activities as High Voltage withstanding aspect,

3. To study and optimize the electrical and thermal concept of such technological assembly. This step includes detailed calculation and optimization of magnetics tools (including software calculation tools),

4. After the manufacturing of an Engineering Model (Elegant Bread Board – EBB), to test the High Voltage Planar technology in a realistic EPC environment. The tests sequence includes a Thermal Vacuum test sequence covering GEO mission needs.

Current Status

The main achievements are: 

In the frame of the project Requirements Review (RR):

• The feasibility study to address the technology to the following TWT tubes has been validated: 150W Ku, 40W Q, 250W Ka, 170W Ka, 300W Ku, 150W C, 75W C, Dual 70W Ka and Compact Dual Ka/Ku TWT’s (80W RF) and for multi-tube constellations market, 

• The confirmation of implementation feasibility has also been successfully performed ; this study included the following tasks: definition of the preliminary mechanical architecture of the technical solution, planar losses optimization, PCB build-up, preliminary thermal analysis and preliminary electrical fields analysis.

In the frame of the project Technical Design Review (TDR):

• Several electrical optimizations have been performed including parasitic capacitors computations and leakage inductance distribution,

• Based on these optimizations, the development of the Planar/PCB build-up has been pushed including thermal and Electrical field analysis,

• The derisking of the PCB technologies including incoming tests definition, High Voltage ageing behavior (with the definition of a specially dedicated representative test vehicle) and materials performances such as outgassing tests and dielectric strength.

In the frame of the project Preliminary Design Review (PDR): 

• The definition of the Elegant Breadboard (EBB) ; designed taking into account the challenge to establish a compromise between high voltage insulation properties and sufficient thermal drain capabilities of the HV planar transformer technology studied in the frame of this project.  The demonstrator definition was based on Quadral EPC adapted to the selected TWT’s, i.e. 170W Ka. Detailed calculation and optimization methods for magnetic, electrical and thermal designs have been performed. The design took into account manufacturing and assembly properties in order to minimize the manufacturing complexity and to ease flexibility during production aiming at a short time to delivery. 

In the frame of the project Final Review (FR) : 

• The planar transformer technology has been exposed to space representative environment. After a first step covering the ground test sequence, a TVAC sequence of 130 thermal cycles has been successfully performed in order to verify the high voltage design and environment effect (including the effect of the local increase of pressure). 10 cold starts at -40°C have also been performed. The test has then been pursued with success with a HV life test at +70°C base plate in order to reach a total test duration of 1500 hours. The test sequence also included thermal characterization under vacuum in order to validate the thermal model related to the evaluated technology.

Companies

Thales Alenia Space Belgium

http://www.thalesgroup.com

Belgium

Objectives

The achievement of high output power requires a higher energetic electron beam. Technological bricks are more and more challenging, developments for components and materials are getting marginal.

In order to achieve a high electronic flow, with reduced geometrical dimensions, an advanced new electron emission device (MMC) is needed, for a constant high beam current density. This MMC device shall be capable for 5 A/cm² electronic flow through the TWT interaction range. Obviously, the electron ejection has to function constantly for more than the 15 years of the cosmic mission life.

The MMC emitter is developed from actual MM-type technology, at THALES as a new high current density electronic source. It allows an increase of the current density by lowering the extraction energy for electronic emission.

The new MMC emitter-design is already in use in telecommunication tubes on ground, for high power TWT’s. The non-terrestrial qualification includes a complete batch of MMC-devices, further specific test vehicles and qualification tubes in order to verify the performance of the MMC devices either by accelerated or standard life testing.

Based on a successful qualification, the MMC emitters will serve THALES’ actual and new development projects, where the high emission current density is mandatory.

Challenges

The development of the MMC emitter for 5 A/cm² with 15 years life time can be considered as an evolution out of the well approved and reliable MM-type technology. By lowering the extraction energy for electronic emission, the MM-technology could be systematically improved and verified. Consequently, the MMC device for non-terrestrial application represents the follow-on for the MM-type emitter, including a general process update, while maintaining the reliability aspects of the actual MM–type emitter. In detail, prior to the qualification of the MMC-emitters a further optimisation step for increasing performance and reliability is done by adjusting the manufacturing processes.

System Architecture

The electron beam is generated by the MMC emitting device. By increasing the current density the electron beam becomes more powerful and a higher output power of the TWT can be reached.

High power TWTs are designed such, that they can handle maximum microwave energy, which is automatically correlated to the tube efficiency. So, – under the consideration of a sufficient margin – the following main parameters are adjusted to their physical / material optima: 

• Temperature

• Thermo-mechanical stress

• Thermal gradients

• Thermal conductivity

• Electrical field strength

• Long-term stability

The MMC electron source has to fulfil all of the above criteria, which sometimes need to choose a compromise on materials and processes. Therefore, the selected materials and processes play an outstanding role in this assembly and need to be chosen very carefully.

Plan

The project is divided into three blocks, each finalized by a dedicated milestone.

The first is focused on the process engineering updated and closed by the Preliminary Design Review (PDR/TRR). 

Followed by qualification tests on subassembly level and specific test vehicles, which were finalized by the Critical Design Review (CDR).  Finally, the qualification test on tube level for a 170W Ku-band TWT THL12170C+ was successfully performed and evaluated for the final review.

Current Status

The qualification campaign of the MMC cathode was successfully performed with real improvements for THALES and their customers. With a significant increase of the permissible emission current density up to 5A/cm² future gun designs can be improved with reduced beam compression and therefore improved beam focusing. The customer can expect improved live time behaviour, due to the fact that a chromium-doped MM cathode will ensure improved barium coverage over a long life time. The cathode size can be potentially reduced due to increased current density or kept constant to replace MM cathodes with improved life time behaviour.

Related Links

• Building Blocks for High Power and High Frequency TWTs
• 500W S-band traveling wave tube
• Ku-Band Developments Including High Power

Companies

Thales Deutschland GmbH

http://www.thalesgroup.com

Germany