J.A. Dupuy

An experimental millimetre wave imaging system

MMW (millimetre wave) imaging is considered as an effective approach to CWD (concealed weapon detection). In this paper, an experimental millimetre wave imaging system based on an aperture synthesis approach is designed. The system is used to scan a metallic object and the resulting field distribution has been recorded. To reconstruct the image, a holographic processing algorithm is applied and a focused image is obtained. The system is active and works at a single frequency, 92.5 GHz. It can be used to investigate the optimized system parameters such as antenna beam width, operating range from the target and aperture array element spacing, etc.

Application of Mathematical Absorber Reflection Suppression to far-field antenna measurements

For some time now, a technique named Mathematical Absorber Reflection Suppression (MARS) has been used successfully to identify and then suppress range multi-path effects in spherical [1, 2, 3, 4], cylindrical [5, 6, 7], and planar [8, 9] near-field antenna measurement systems. This paper details a recent advance that, for the first time, allows the MARS measurement and post-processing technique to be successfully deployed to correct antenna pattern data taken using direct far-field or compact antenna test ranges (CATRs) where only a single great circle cut is acquired. This paper provides an overview of the measurement and novel data transformation and post-processing chain that is utilised within the far-field MARS (F-MARS) technique to efficiently correct far-field, frequency domain data. Preliminary results of range measurements that illustrate the success of the technique are presented and discussed.

An investigation of antenna element spacing on the quality of millimetre wave imaging

In this paper, a high gain horn which has a 10 degree beam width is used as the scanning antenna in a monostatic millimetre wave imaging radar system. The distances from the antenna to the object to be imaged are set in the near and far field range respectively. The backscattered electric field from the object is recorded from the measurement and an image is reconstructed by applying holographic processing algorithm. The investigation of the minimum required sampling density to form the target image is performed by varying the sampling density. Since the synthetic aperture is equivalent to the imaging array, the investigation provides vital information for millimetre wave imaging array design.

Design of UWB antenna for Autonomous Interference Monitoring System (AIMS)

An ultra-wide band (UWB) antenna sub-system has been developed for testing the Autonomous Interference Monitoring System (AIMS) capabilities in a set of field trials scheduled for UK Office of Communications (Ofcom), the independent regulator and competition authority for the UK communications industries. The prototype antenna is a compact planar structure and easy-to-install, thus reducing the planning permission constraint for equipment testing. A satisfactory radiation pattern across the whole frequency range has been achieved. Furthermore, the antenna has been designed to be able to receive horizontally polarised TV transmission signal at around 400 MHz. The UWB antenna sub-system has also been designed to be weather-proof and offer low wind resistance