The first large-scale compact antenna test range
In 1989, the very first large-scale compact range for measuring antennas on satellites was built at ESTEC in Noordwijk, the Netherlands according to a design by Knud Pontoppidan of TICRA. The test range is named the Compact Payload Test Range and it is large enough to fit the entire payload of a satellite.
To measure the far-field properties of an antenna requires a far transmitter, often several hundred meters so the field reaching the antenna is a plane wave. To measure the pattern at such large distances will inevitably include inaccuracies stemming from external sources or – in particular – from interfering signals from reflections in the ground or nearby buildings. This may be avoided when the measurements are carried out in a shielded anechoic chamber.
To generate a plane wave at a short distance as in an anechoic chamber is a demanding task when the antenna under test is large. The principle is to apply two large reflectors to collimate the field from a transmitting feed to a plane wave illuminating the antenna under test. The plane wave will be disturbed by scattering from the edges of the reflectors. To reduce these edge effects the edges are designed with long teeth which – so to speak – blur the sharpness of a straight edge.
In the ESTEC Compact Payload Test Range, the large reflectors are built in sectors, four horizontal ‘strips’, each 10 m long, 2 m wide. They are built by CASA in Spain in a glass fiber reinforced resin. Today, high precision Compact Ranges with 12m x 14m reflectors are commercially manufactured in cast iron by Astrium GmbH.