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Notch Antennas

Reflector Systems

Passive Components

Multiband Systems

Wideband Systems

Installed Performance

High-power Components

Work at Millimetre Wavelengths

Dr. Foster worked at frequencies above 30 GHz during the late sixties when she was head of a radio-astronomy group which designed, built and maintained a dual reflector of 15.0 m diameter for 35 GHz. Waveguide components such as rat-races, splitters and a dual horn system for a switching radiometer were designed and built in-house. The scientific work was mostly on the Solar System and on propagation [1], [2], [3].

Later, work at ERA was concerned with the design and build of a small 60 GHz system for communications and some radiometer work [4], [5].

Since she set up MAAS, it has carried out work on a number of mmwave projects including

  1. Design of reflector antenna systems and the associated quasi-optical feed systems for the meteorological spacecraft, AMSU-B [6] and Meteosat-A. MAAS provided the design for the reflector system for AMSU-B and has worked on the European successor to AMSU-B. The complete Quasi-Optics chain was modelled using a mixture of Spherical Wave Mode Expansions and Physical Optics.
  2. Computation of the TT&C installed performance on RADARSAT.
  3. Work for the European Space Agency on assessing the possible methods of measuring high-performance antennas at frequencies between 80 and 200 GHz [7]. This work was carried out with Queen Mary and Westfield College and resulted in the QMW Compact Antenna Test Range (CATR) being developed for the qualification of the RF system performance of AMSU-B.
  4. Work on errors in quasi-optics systems [9].
  5. Work on modelling a load for frequencies between 180 and 900 GHz. Finite Difference Time Domain techniques have been used.
  6. Work for the European Space Agency on assessing the possible methods of measuring high-performance antennas at frequencies between 200 and 1500 GHz. This examined a wide range of techniques from the use of CATRs to holography. The use of computational techniques and high accuracy physical measurement were also examined. The availability of sources and detectors of adequate performance have been examined as well as the current state-of-the-art in RAM for these frequencies. For this contract, MAAS was the lead contractor and the subcontractors included establishments in Denmark, Finland and the United Kingdom [10], [11].
  7. Work on design of dual-band lens+horn system for mass production (28.5 GHz and 41.5 GHz). This is now in production by Thomas Keating Ltd.
  8. Design, manufacture and test of a shaped Gregorian reflector system for CP at 94.5 GHz

Multi-band antennas for passive radiometers in space have also been designed.

REFERENCES

  1. Foster P R, Flett A M and Howie I M, `Atmospheric Noise at 33.5 GHz', Nature, 221, 1969, p169
  2. Foster P R, `Atmospheric Effects at 9 mm Wavelength', Trans IEEE on Ant and Prop, AP-17, 1969, p684
  3. Foster P R and Thornton D C, `The Measurement of Atmospheric Attenuation at 9 mm Wavelength', IEE Conf on Propagation of Radiowaves above 10 GHz, 1973, p127
  4. Foster P R and Rudge A W, `60 GHz Antenna-System Design', Part 1 Millimetre-wave Components and Technology Survey, ERA Report
  5. Williams N and Foster P R, `Millimetric Wave Antennas and Associated Components', Electronic Engineering, April 1978, p77 - 81
  6. Foster P R and Tatnall A R L, `Multiband Antenna for AMSU-B',IEE Colloquium on Multiband Antennas, 1987
  7. Foster P R, Olver A D and Parini C, `Limitations in the Determination of Beam Efficiency for Millimetrewave Antennas', 11th ESTEC Workshop on Antenna Measurements, Gothenburg, 1988, p163 - 168
  8. Foster P R et al., `Survey of Millimetrewave Antenna Test Ranges', ESTEC Purchase Order 74178, July 1988
  9. Foster P R and Wylde R J, `The Effect of Quasi-optics Errors on Reflector Antenna Performance', Trans IEEE, MTT-60, No 6, 1992
  10. G Lemanczyk, P de Maagt and P R Foster, `Problems of Antenna Measurement in the Terahertz Frequency Range', IEE Colloquium on Terahertz Technology, Dec. 1996.
  11. P R Foster, `Antenna Measurements to 1.5 THz', Invited Paper, JINA 96.
  12. J Ala-Laurinaho, P R Foster et. al, "Comparison of Antenna Measurement Techniques for 200 to 1500 GHz", ESTEC Antenna Workshop June 1997, WPP-128 p345-350