PLDRO – Development of key technologies for frequency generators


New frequency generators developed by SpaceForest in cooperation with RUAG Space AB.


The project objectives were related to the activities realized by ESA under the TRP (Basic Technology Research Programme) program. The TRP supports projects for deep space missions, where optimization of the circuit and reduction of the power usage is very important.


Project “Development of key technologies for frequency generators” project was focused on the design and manufacturing of a high reliability and performance frequency generator.


The main technical objectives:

• design of all modules of frequency generators

• simulation and optimization of subsequent versions of generator subsystems

• manufacture and assembly of breadboard frequency generators

• verification and validation of a design with physical testing (measurements) according to the technical requirements


In order to meet the requirements, the concept of the frequency generator is based on Phase locked Loop (PLL) and Dielectric Resonator Oscillator (DRO). The use of dielectric resonator allows to obtain pure and temperature stable output signals.


Three very stable generators were designed, manufactured and measured meeting stringent phase noise requirements


PLDRO generator model
PLDRO generator model


PLDRO Test rusult
PLDRO Test rusult


A generator is stable during temperature changes and has a great potential for minimization.

A frequency generator based on the outcome of this solution could be used in some upcoming ESA science missions. The examples are:

  • JUICE (JUpiter ICy moons Explorer), planned to be launched in 2022
  • PLATO (Planetary Transits and Oscillations of stars), planned to be launched in 2024. Both of these scientific missions will utilize the X-band or other bands for at least part of communications.

Generators can reach the TRL 6 or TRL 7 or higher level before the production of subsystems for these missions begin.