European Space Agency

Ka-band LNA Redundancy Switches

Objectives

The demand for Ka band telecommunications has expanded significantly in the last few years. This growth is expected to continue with the need for greater bandwidth in order to cater for the ever increasing requirements of broadband internet, broadcast TV, and other high speed data applications.

The standard Ka band system uses Ka band Low Noise Amplifiers (LNAs). Since the LNA is a crucial element in the receive chain, some type of redundancy scheme is employed to improve the overall reliability.

At frequencies lower than Ka band, electro-mechanical switches have historically been used as standard on LNA redundancy schemes. However, as the frequencies increase into the Ka band, alternative switch technologies, in particular ferrite based, become more attractive. This is mainly because as the frequencies increase, the LNA, waveguide dimensions, and ferrite switches decrease in size, whereas the electro-mechanical switches do not.

Despite the current demand for a ferrite based LNA redundancy switch solution, a European-sourced product is not available. The current sources are from US companies whose products are ITAR controlled. The intention of the proposed development is to design, develop, manufacture and market a ferrite based LNA redundancy switch capability which is European sourced, non ITAR, and with guaranteed future supply.

Challenges

Component selection is a major issue since the system needs to be inexpensive but also needs to be able to meet the stringent requirements of a space mission.

Size and mass of the unit needs to be limited whilst retaining flexibility of a varying quantity of switch heads depending on customer requirements.

Benefits

One of the most important benefits is the availability of a Ka Band ferrite based switch which is smaller and lower mass than present electro-mechanical switches. This will result in a switch solution which is more mechanically compliant with current and future designs.

Another benefit will be the switch being European sourced and entirely export/restriction free (e.g. non ITAR).

Features

The proposed system will make use of ferrite based junctions to provide low mass, low envelope switching elements (RF Switch Heads) while providing good RF performance (insertion loss, isolation and return loss). Centralised electronics, consisting of Switch Driver, Telecommand Interface, and Power Supply Interface, will be shared between a large number of RF Switch Heads, thus leading to reduced system costs. The system will be non-ITAR making it attractive to the largest range of customers.

Plan

The overall duration of the project is 2 years and will be executed in 4 phases:

  1. Design and Development Planning,
  2. RF Head Breadboard and Preliminary Electronics Design:
    • De-risk and characterise the newly designed Ka Band RF Head,
    • Design of the electronics and RF Head Monobloc.
  3. Development Model – Initial assembly and test of the combined electronics and RF Head Monobloc,
  4. Engineering Qualification Model – the primary purpose will be to verify the manufacturing processes to ensure repeatability in future repeat orders.

Current status

Currently the project has completed design and development planning and is undergoing the RF head breadboard and preliminary electronics design activities.

Status date

Wednesday, July 31, 2013 - 09:54