Ground stations developments for VHTS applications

Status

Ongoing
Status date

2025-10-07
Activity Code

6B.088

Objectives

Define, analyse and calculate technical main performances for a tri-band ground Very High Throughput Satellite (VHTS); stations operating in Ka Tx, Q Rx and V Tx band widths;
Define the architectures and calculate the technical main performances for a quadri-band ground VHTS stations operating in Ka Rx, Ka Tx, Q Rx and V Tx band widths;
Improve the AC power consumption of a VHTS ground station.

Challenges

As VHTS applications require a high level of radio frequency (RF) performances operating up to 52.4 GHz, new high efficiency optics for 9-metre and 13-metres class ground antenna shall be designed considering all environmental constraints, and minimising the power consumptions.

For the new quadri-band antenna, different architectures shall be proposed and evaluated. The most relevant ones shall be deeper analysed. Simultaneous operations in four Telecom bandwidths from 18 to 52 GHz does not exist and represent a high challenge.

Finite element analysis covering all load cases are needed to perform accurate antenna RF analysis.

Benefits

Our approach is divided in two main configurations:

A common tri-band architecture for 9 metres and 13 metres covering three bandwidths: Tx Ka - Rx Q –Tx-V;
A common quadri-band architecture by adding Ka Rx.

The quadri-band architecture for 9-metre or 13-metre class ground antenna does not exist, and has never been proposed to customers (e.g. operators: it is really a product allowing to Thales Alenia Space to offer a new solution, minimising the number of ground antenna, and the associated cost).

The tri-band architecture offers optimised antenna performances, higher EIRP and G/T, with full band widths on Tx Ka - Rx Q and Tx-V

For all configurations, a new design of the oversized antenna hub improves access for maintenance purposes.

Features

The main RF performances of both products (9-metre / 13-metre antenna) are based on major critical subsystem:

The 9.30-metre reflector based on new panels technology, and a high stiffness back up structure;
The 13.50-metre reflector based on new panels technology and a high stiffness back up structure;
A common oversized antenna hub, allowing to integrate the Tx and Rx chains, close to the feed interfaces, minimizing the losses;
For both products, a new Cassegrain optic offering the best compromise between RF and mechanical constraints;
Two new quadri-band architectures based on a quadri-band feed and a solution using a dichroic separating bandwidths;
State of the art for Q-band and Ka-band low noise amplifiers are used to calculate G/T of the antenna.

System Architecture

The tri-band (Ka Tx – Q Rx – V Tx) architecture is made of:

The tri-band feed is an existing equipment previously designed by Thales Alenia Space: it is a main input for the tri-band architecture;
A Cassegrain optic based on a 9.30-metre 13.50-metre main reflector and a sub reflector;
A high-stiffness 9.30-metre and 13.50-metre main reflector with new panels offering low mechanical deformations, as requested by V band operations;
An oversized antenna hub, allowing to integrate all RF equipment and associated cabinets.

Two quadri-band (Ka Rx-Ka Tx – Q Rx – V Tx) architectures have been evaluated; they are based on:

A quadri-band feed with monopulse capability in Q-band (this product is not part of the Advanced Research in Telecommunications Systems (ARTES) project);
A dichroic mirror with two feeds;
As for the tri-band architecture, high-stiffness 9.30-metre and 13.50-metre reflectors.

Plan

The following main phases are considered, with associated milestones:

A first phase covering the preliminary design of the 9-metre and 13-metre tri-band antenna, and power consumption of a VHTS ground station;
An engineering design phase for the Ka band LNA and panels technology;
The evaluation of quadri-band architecture concepts;
A design phase covering FEA and RF activities, allowing to present final antenna performances, and final design reports
A test phase for panels and Ka-band LNA;
Finally, evaluation of dichroic mirror concepts has been studied, with manufacturing and RF tests on samples.

Current status

The project should be closed shortly considering the following status:

A preliminary design review was held in April 2023;
The quadri-band concepts were presented in July 2023 (phase 1) and completed from December to June 2024;
The final report covering power consumptions analysis has been delivered in July 2024;
Design reports covering RF and mechanical activities were supplied in November 2024;
TRR and FAT of Ka-band LNA were done in August 2024 and February 2025;
Dichroic mirrors activities started in June 2024; final review is expected in October 2025.