Ka Ingenious Space Solutions (KISS) - 25/17 GHz Communications Down-Converter

Status date
Ka band market has recently significantly evolved: new programs show a great step from slow and cautious introduction of Ka Band systems to full confidence in them. Requests for proposal (RFP) and programs have convinced THALES ALENIA SPACE to continue and deepen its reflections at system point of view by taking into account recent trends, propose innovations and demonstrate their feasibility. 
It is in particular the case for new frequency plan dedicated to HDTV mission (25/17 GHz).
Reverse band corresponds to 24.75-25.25 GHz in Rx and 17.3-17.8 GHz in Tx. These bandwidths are available for BSS over Americas (ITU region 2) from April 2007. The use of 17.3-17.8 GHz as downlink is allowed only if 24.75-25.25 GHz is used as Uplink. The aim is to introduce broadband services supplying a combination of video, audio, data, video on demand, and multimedia service both at regional and national level. 
These considerations and recent requests from satellite operators push THALES ALENIA SPACE to boost the development of a 25/17 GHz Down-Converter (EQM) in order to offer competitive solution at equipment level.
RF sections are based on macro-hybrid package technology and MMIC chipset dedicated to address frequency plan.
MMIC chipsets are available in THALES for 20 & 30 GHz amplification, but their performance have to be checked in 17 & 25 GHz bands, mainly for MMIC Mixer, Low Noise Amplifier & High Power Amplifier, funded on ESA or THALES previous programs.
Preliminary measurement on Low Noise Amplifier MMIC & simulation on High Power Amplifier MMIC gives THALES lot of confidence of use of these available MMICs for 25 & 17 GHz RF sections.
For MMIC mixer it is necessary to design & manufacture a new MMIC to achieve the frequency translation 25 to 17 GHz.
Wave-guide WR34 interface RF macro-package available design has to be shift from 30 to 25 GHz on order to optimize NF & input return losses of the Down-Converter.
Main activities will then concern layout definition of RF chain inside macro-package, with enough flexibility in order to address various specifications in the specified envelope.
In order to improve manufacturing efficiency, it is also proposed to evaluate and qualify replacement of brittle DC beads with alumina window. This solution shall allow to reduce hybrid devices hermeticity non-compliance due to DC beads cracks risk during mating & de-mating operations.
LO section for EQM1 is based on standard building blocks for internal LO architecture, including Dielectric Resonator VCO, Sampling Phase Detector Hybrid Device and Phase Locked Loop PCB with Oven Controlled Crystal Oscillator.
LO section for EQM2 will integrate a new full MMIC Sampling Phase Detector Hybrid Device and a new Phase Locked Loop PCB with Oven Controlled Crystal Oscillator to reduce cost.
DCDC section is based on the new power supply generation called Flex3
  • To develop and present a competitive product for this new emerging market,
  • To reduce mass compared to existing Ka-band products.

Thales Alenia Space proposes to develop a stand-alone Down-Converter dedicated to new RF spectrum allocation for Broadcasting Space Systems in 25 and 17 GHz in order to be able to present competitive products in this emerging market.

The development effort is focused on the 3 main parts of the down converter:

  • RF section design to comply with new frequency range,
  • The Local Oscillator section with technological and industrial improvements allowing overall mass and cost reduction,
  • The DC/DC section is also modified to cope with the new RF section and with the modified LO. Cost and mass have also been improved.

The new product has a modular and flexible architectures allowing easy adaptation to major primes platforms specifications.

The 25/17 GHz Down-Converter unit will be based on a RF macro-hybrid device, gathered with internal LO & DCDC sections.

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25/17 GHz Down Converter mechanical design

Main Characteristics

Useful Input Frequency Range 24750 - 25250 MHz
Input Levels
Maximum Input Level
Input level dynamic range
-65 dBm
30 dB
Local Oscillator Frequency 7450 MHz
Useful Output Frequency Range 17300 - 17800 MHz
Minimum Gain 64 dB
Gain stability Over qualification temperature range +/- 1.2 dB
Noise Figure
At ambient temperature, at any frequency
2.35 dB
Amplitude Linearity 50 dBc
Out of band response

Gain at receive frequency
Gain at receive frequency

< Nominal gain-55 dB
< Nominal gain-55 dB
Phase Noise
100 Hz
1 kHz
1 MHz
> 10 MHz
-72 dBc/Hz
-90 dBc/Hz
-105 dBc/Hz
-130 dBc/Hz
Mass and dimensions 710 g
Power bus/DC Power consumption 13W

The EQM activities are organized in two phases:

Phase 1:
Key milestones of phase 1 are the Baseline Design Review (BDR), MTR (Mid Term Review) and FR1 ( final review one).

  • MMIC Mixer: Design, foundry and test,
  • MMIC SPD : design and foundry,
  • Dcdc converter Flex3 design,
  • Macro-hybrid design,
  • EM dcdc converter Flex3 manufacturing and test,
  • EM macro-hybrid manufacturing and test,
  • At the BDR, the EQM1 unit design is presented together with EM dcdc converter test report, Mixer design sheet and measurement sheet specifications,
  • EQM1 manufacturing and test,
  • Macro-hybrid CTA manufacturing and test,
  • At the MTR (CDR data package), the EQM2 detailed design is presented. In addition the qualification test procedure will be presented,
  • At FR1 EQM1 qualification test reports, macro-hybrid CTA reports will be presented.

Phase 2:
This phase starts after the FR1 and EQM1 qualification tests completion. Following tasks are driven:

  • New MMIC SPD hybrid device and PLL board manufacturing & testing
  • MMIC SPD CTA manufacturing and test
  • Implementation of the two new circuits in EQM unit for EQM2 configuration
  • EQM2 qualification test sequence

The key milestone of phase 2 is the FR2. During this review, EQM2 qualification tests results will be presented together with CTA SPD report.

Current status
  • All key reviews (BDR/CDR/MTR/FR1 & FR2) have been held successfully,
  • The 25/17 GHz Down-converter has been fully tested and qualified with expected performances and under multi-platform environmental conditions,
  • RF Macro-hybrid is qualified (CTA report),
  • MMIC SPD hybrid is qualified (CTA report).

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EQM 25/17 GHz Down-converter