Prof. Nuno Borges Carvalho

Transcription

1 Prof. Nuno Borges Carvalho Dept. Electrónica, Telecomunicações e Informática Instituto de Telecomunicações Universidade de Aveiro nbcarvalho@ua.pt GaN RF New Generations for Space Telecom

2 Prof. Nuno Borges Carvalho Dept. Electrónica, Telecomunicações e Informática Instituto de Telecomunicações Universidade de Aveiro nbcarvalho@ua.pt Intituto de Telecomunicações Aveiro-Pole

3 -> IT Aveiro -> Radio Systems Software Defined Radio Receiver Dynamic Range Increase Radios Systems Characterization and Design Software Defined Radio Transmitter Efficiency RF-DC Converter Efficiency Analysis of nonlinear behavior for: Power Measurements Wireless Power Transmission

4 RF Payloads RF Payloads impose high value of power been delivered to earth Travelling Wave Tube Amplifiers TWTA Still been used intensively in space applications

5 Evolution of RF Payload Power Transmission TWTA Heavy, Expensive, big sized GaAs Low Power capabilities, good for low noise applications GaN Promissing Technology for high power and also low noise applications

6 Evolution of RF Payload Power Transmission Why GaN on space? Power and Frequency Theoretical limits for Si, GaAs and GaN devices Maximum Power (W) GaN GaAs Si Commercial Communications Base Stations X-Band Military Radar Commercial Satcom Transmitters (VSAT-1MBPS) Frequency (GHz) Commercial Broadband Satcom (VSAT-16MBPS)

7 Introduction and motivation» AlphaSat project and Participants

8 Introduction and motivation The main objective of the project is to test GaN Technology in space, mainly European versions.

9 GaN Technology o Transistor technology suplied by FBH ( Fredinand-Braun-Institut) o o o Cosmic radiation immunity High frequency operation High power handling

10 Circuit Selection o Amplifier Pros: Optimum for mimic future applications of GaN technology onboard of satellites, possibility to study TWTA future changes. Cons: High values of consumed power, need for external signal source and driver circuit, mass increase due to several circuits need for data gathering. o Oscillator Pros: No need for extra signal excitation sources, possibility of including all circuitry and its measurement systems inside the same box, reduction of power consumption and mass. Cons: Do not excite all characteristics of the technology under study. Selected Circuit

11 Oscillator Circuit o o o Oscillator based on traditional Colpitz configuration Frequency of oscillations imposed by payload restrictions (near 2GHz) Ceramic resonator for high Q

12 Oscillator Circuit o o Prototype should consider high frequency oscillations due to impressive transistor quality Oscillations near 12-15GHz. D2 D1 Stubs for high frequency spurious reduction Measurement circuit Power measurement

13 Oscillator Prototype Optimization of size and box weight, hardness» Concerns with material CET, electrical and thermal conductivity.» Gold wire for bonding» Epoxy glues to attach chip» Adhesives glues to PCB» Nickel and gold plating» Bonding with gold wire

14 Oscillator Prototype

15 Oscillator Prototype Thermal test cycles Between -20ºC and 70ºC a maximum frequency drift of 12 MHz.

16 Oscillator Prototype Vacuum tests To avoid any particles or gases released not expected

17 Oscillator Prototype EMC tests - US Military, agreement concern M a r k e r : 2. 2 G Hz d Bµ V/ m L e v e l [ d Bµ V/ m ] x + x + x G 2. 2 G 2. 4 G 2. 6 G 2. 8 G 3G 3. 2 G 3. 6 G F r e q u e n c y [ Hz ] x M ES CT T B_ EBB_ 1 1 _ r e d + M ES CT T B_ EBB_ 1 1 _ r e d 2 M ES CT T B_ EBB_ 1 1 _ p r e M ES CT T B_ EBB_ 1 1 _ p r e 2

18 Overall experiment

19 Final prototype Oscillators: Supply and control RF power, Id Supply values temperature Radiation level measurements

20 Challenges University of Aveiro Approach Improved Radios will have impose cleaver ways to power management. This implies that radios will have intelligence from its own. FM Radio Radio over 3G Radio over TDT DAB Satellite LTE 1º Prémio PLUG APRITEL 2010

21 Acknowledgements We would like to thank the fruitful discussions with: Prof. José Carlos Pedro, Prof. Nuno Matos and Eng. Cupido Prof. Mendiratta and Eng. Jorge Monteiro for the vacuum tests and finally to Portuguese Communications Authority (ANACOM) for the electromagnetic compatibility tests.

22 Post graduation in Radio System Design Start Apr POSRAD is an advanced postgraduate course that offers an opportunity for electrical engineers to update and advance their knowledge on the area of wireless communication systems. posrad.web.ua.pt